Primary, secondary, and tertiary interventions to reduce the morbidity and mortality of preterm birth

Cervical cerclage vs cervical pessary in women with cervical insufficiency: A multicentric, open-label, randomised, controlled pilot trial [the CEPEIC trial]

Objective

Cervical insufficiency accounts for 8 % of preterm births. Pessary and cerclage are considered preventive approaches for preterm birth. These interventions were compared in terms of reducing the prematurity rate in women with previous preterm birth, due to cervical insufficiency or due to having a short cervix in their current pregnancy.

Methods

This was a prospective, multicentric, open-label, randomised, pilot, controlled trial. Participants were women with singleton pregnancies who had previous preterm birth caused by cervical insufficiency or previous preterm birth and a short cervix [≤ 25 mm] in their current pregnancy. Women were randomised [1:1] to either cerclage or pessary. The primary outcome was to assess the feasibility of a trial on cervical pessary vs. cerclage to prevent preterm birth before 34 weeks in women with cervical insufficiency. As a secondary outcome, we studied the morbidity rate of the pessary versus the cerclage in women with cervical insufficiency and assessed the financial impact of using both devices in these women. The sample size was calculated based on the estimated population that we could potentially recruit: 60 women, 30 for each group, to ascertain whether the rate of preterm birth < 34 weeks of gestation may be reduced from 34 % to at least 27 % in the pessary group, as in the results obtained with the cerclage.

Results

No significant differences in preterm birth < 34 weeks of gestation were observed in our study, although it was underpowered to detect these differences [the relative risk [RR] of PB < 34 weeks of gestation was 0.8 [95 % CI: 0.31-2.09, p = 0.888]. The rates of obstetric and perinatal complications were similar for both devices [15 cases in both groups, 50 % of cases [RR; 0.6-1.68; p = 1]. Cervical pessary had fewer secondary effects than the cerclage [less bleeding at insertion in the pessary group compared with cerclage, 1 case vs 14 cases, p < 0.001; less pain at removal in the pessary group compared with cerclage, 14 vs 22 cases. p = 0.042 and less bleeding, 2 cases vs. 10 cases, p = 0.027].

Conclusions

Pessary does not seem less effective than cerclage, although these findings need to be confirmed in a larger randomised controlled trial. Pessary had fewer secondary effects than cerclage both at insertion and removal.

Sinopsis

Cervical pessary does not seem to be less effective than cerclage. Cervical pessary had fewer secondary effects than cerclage.

Clinical and dental predictors of preterm birth using machine learning methods: the MOHEPI study

Preterm birth (PTB) is one of the most common and serious complications of pregnancy, leading to mortality and severe morbidities that can impact lifelong health. PTB could be associated with various maternal medical condition and dental status including periodontitis. The purpose of this study was to identify major predictors of PTB among clinical and dental variables using machine learning methods. Prospective cohort data were obtained from 60 women who delivered singleton births via cesarean section (30 PTB, 30 full-term birth [FTB]). Dependent variables were PTB and spontaneous PTB (SPTB). 15 independent variables (10 clinical and 5 dental factors) were selected for inclusion in the machine learning analysis. Random forest (RF) variable importance was used to identify the major predictors of PTB and SPTB. Shapley additive explanation (SHAP) values were calculated to analyze the directions of the associations between the predictors and PTB/SPTB. Major predictors of PTB identified by RF variable importance included pre-pregnancy body mass index (BMI), modified gingival index (MGI), preeclampsia, decayed missing filled teeth (DMFT) index, and maternal age as in top five rankings. SHAP values revealed positive correlations between PTB/SPTB and its major predictors such as premature rupture of the membranes, pre-pregnancy BMI, maternal age, and MGI. The positive correlations between these predictors and PTB emphasize the need for integrated medical and dental care during pregnancy. Future research should focus on validating these predictors in larger populations and exploring interventions to mitigate these risk factors.

Young hearts, early risks: novel cardiovascular biomarkers in former very preterm infants at kindergarten age

BACKGROUND

Preterm birth is associated with long-term cardiovascular morbidity and mortality. In adults, fibroblast growth factor-23 (FGF-23), α-Klotho, and secretoneurin have all garnered attention as cardiovascular biomarkers, but their utility in pediatric populations has not yet been ascertained. The aim of this pilot study was to evaluate these novel cardiovascular biomarkers and their association with indicators of cardiovascular impairment in the highly vulnerable population of former very preterm infants.

METHODS

Five- to seven-year-old children born at < 32 weeks' gestation were eligible for the study. Healthy same-aged children born at term served as controls. Biomarkers were quantified in fasting blood samples, and echocardiographic measurements including assessment of aortic elastic properties were obtained.

RESULTS

We included 26 former very preterm infants and 21 term-born children in the study. At kindergarten age, former very preterm infants exhibited significantly higher plasma concentrations of biologically active intact FGF-23 (iFGF-23; mean 43.2 pg/mL vs. 29.1 pg/mL, p = 0.003) and secretoneurin (median 93.8 pmol/L vs. 70.5 pmol/L, p = 0.046). iFGF-23 inversely correlated with distensibility of the descending aorta.

CONCLUSION

In preterm-born children, iFGF-23 and secretoneurin both offer prospects as valuable cardiovascular biomarkers, potentially allowing for risk stratification and timely implementation of preventive measures.

IMPACT

Former very preterm infants have increased plasma concentrations of the novel cardiovascular biomarkers intact fibroblast growth factor-23 (iFGF-23) and secretoneurin at kindergarten age. Increases in iFGF-23 concentrations are associated with decreased distensibility of the descending aorta even at this early age. Monitoring of cardiovascular risk factors is essential in individuals with a history of preterm birth. Both iFGF-23 and secretoneurin hold promise as clinically valuable biomarkers for risk stratification, enabling the implementation of early preventive measures.

Screening for women at risk of spontaneous preterm birth, including cervical incompetence

Preterm births remain one of the biggest challenges in obstetrics worldwide. With the advancement of neonatal care, more premature neonates survive with long term consequences. Therefore, preventing or delaying preterm births starting from the preconceptional or antenatal periods are important. Among the numerous screening strategies described, not one can fit into all. Nonetheless, approaches including identifying women with modifiable risk factors for preterm births, genitourinary infections and short cervical length are the most useful. In this article, the current evidence is summarized and the best strategies for common clinical scenerios including cervical incompetence, history of second trimester loss or early preterm births, incidental short cervix and multiple pregnancy are discussed.

Effect of probiotic administration to breastfeeding mothers with very low birthweight neonates on some neonatal and maternal outcomes: study protocol for a randomised, double-blind, placebo-controlled trial

INTRODUCTION

Premature birth and very low birth weight (VLBW) are leading causes of neonatal mortality. Almost all premature infants experience hyperbilirubinaemia. Administering probiotics to breastfeeding mothers may positively affect infant outcomes. This trial aims to investigate whether probiotic supplementation for mothers with VLBW infants affects total serum bilirubin levels and postpartum depression scores (primary outcomes), as well as some other neonatal and maternal outcomes (secondary outcomes).

METHODS AND ANALYSIS

This is a randomised, double-blind, placebo-controlled superiority trial with two parallel arms. Participants, caregivers and outcome assessors will be blinded. A total of 122 breastfeeding mothers of neonates with a birth weight of 1000-1500 g, along with their infants within 48 hours of birth, will be assigned to either the probiotic or placebo group in a 1:1 ratio through block randomisation, stratified by singleton and twin births. The intervention will involve oral administration of probiotics containing Lactobacillus paracasei 431 and Bifidobacterium lactis BB-12, or an indistinguishable placebo, for 42-45 days. Outcomes will be assessed through daily observations, laboratory assessments and the Edinburgh Postpartum Depression Scale. Adverse events will also be documented. Modified intention-to-treat analyses will be employed for the primary and secondary outcomes, excluding participants lost to follow-up from all postintervention assessments.

ETHICS AND DISSEMINATION

This study protocol has been approved by the Medical University of Tabriz Ethics Committee (IR.TBZMED.REC.1401.735). Findings will be disseminated through publication in a peer-reviewed journal and presentations at relevant conferences.

TRIAL REGISTRATION NUMBER

IRCT20100414003706N42.

Dynamic changes in place-based measures of structural racism and preterm birth in the USA

BACKGROUND

Structurally racist systems, ideologies and processes generate and reinforce inequities among minoritised racial/ethnic groups. Prior cross-sectional literature finds that place-based structural racism, such as the Index of Concentration at the Extremes (ICE), correlates with higher infant morbidity and mortality. We move beyond cross-sectional approaches and examine whether a decline in place-based structural racism over time coincides with a reduced risk of preterm birth across the USA.

METHODS

We used as the outcome count of preterm births overall and among non-Hispanic (NH) black and NH white populations across three epochs (1998-2002, 2006-2010, 2014-2018) in 1160 US counties. For our measure of structural racism, we used ICE race/income county measures from the US Census Bureau. County-level fixed effects Poisson models include a population offset (number of live births) and adjust for epoch indicators, per cent poverty and mean maternal age within counties.

RESULTS

An SD increase in ICE (0.11) over time corresponds with a 0.6% reduced risk of preterm birth overall (incidence rate ratio (IRR): 0.994, 95% CI 0.990, 0.998), a 0.6% decrease in preterm risk among NH black births (IRR: 0.994, 95% CI 0.989, 0.999) and a 0.4% decrease among NH white births (IRR: 0.996, 95% CI 0.992, 0.999).

CONCLUSIONS

Movement away from county-level concentrated NH black poverty preceded reductions in preterm risk, especially among NH black populations. Our longitudinal design strengthens inference that place-based reductions in structural racism may improve perinatal health. These improvements, however, do not appear sufficient to redress large disparities.

Maternal inflammatory and microbial drivers of low birthweight in low- and middle-income countries

BACKGROUND

Low birthweight (LBW) is when an infant is born too soon or too small, and it affects one in seven infants in low- and middle-income countries. LBW has a significant impact on short-term morbidity and mortality, and it impairs long-term health and human capital. Antenatal microbial and inflammatory exposure may contribute to LBW.

METHODS

Ovid-Medline, Embase and Cochrane databases were searched for English-language articles evaluating inflammatory, microbial or infective causes of LBW, small-for-gestational age, intra-uterine growth restriction or prematurity. Inclusion criteria were human studies including published data; conference abstracts and grey literature were excluded. A narrative synthesis of the literature was conducted.

RESULTS

Local infections may drive the underlying causes of LBW: for example, vaginitis and placental infection are associated with a greater risk of prematurity. Distal infection and inflammatory pathways are also associated with LBW, with an association between periodontitis and preterm delivery and environmental enteric dysfunction and reduced intra-uterine growth. Systemic maternal infections such as malaria and HIV are associated with LBW, even when infants are exposed to HIV but not infected. This latter association may be driven by chronic inflammation, co-infections and socio-economic confounders. Antimicrobial prophylaxis against other bacteria in pregnancy has shown minimal impact in most trials, though positive effects on birthweight have been found in some settings with a high infectious disease burden.

CONCLUSION

Maternal inflammatory and infective processes underlie LBW, and provide treatable pathways for interventions. However, an improved understanding of the mechanisms and pathways underlying LBW is needed, given the impact of LBW on life-course.

Assessment of current biomarkers and interventions to identify and treat women at risk of preterm birth

Preterm birth remains an important global problem, and an important contributor to under-5 mortality. Reducing spontaneous preterm birth rates at the global level will require the early identification of patients at risk of preterm delivery in order to allow the initiation of appropriate prophylactic management strategies. Ideally these strategies target the underlying pathophysiologic causes of preterm labor. Prevention, however, becomes problematic as the causes of preterm birth are multifactorial and vary by gestational age, ethnicity, and social context. Unfortunately, current screening and diagnostic tests are non-specific, with only moderate clinical risk prediction, relying on the detection of downstream markers of the common end-stage pathway rather than identifying upstream pathway-specific pathophysiology that would help the provider initiate targeted interventions. As a result, the available management options (including cervical cerclage and vaginal progesterone) are used empirically with, at best, ambiguous results in clinical trials. Furthermore, the available screening tests have only modest clinical risk prediction, and fail to identify most patients who will have a preterm birth. Clearly defining preterm birth phenotypes and the biologic pathways leading to preterm birth is key to providing targeted, biomolecular pathway-specific interventions, ideally initiated in early pregnancy Pathway specific biomarker discovery, together with management strategies based on early, mid-, and-late trimester specific markers is integral to this process, which must be addressed in a systematic way through rigorously planned biomarker trials.

Leveraging biosocial methods to examine and address structural determinants of health and promote health equity

BACKGROUND

Biosocial approaches in nursing research have largely focused on the ways that social determinants of health influence individual-level outcomes, including symptom management, family and social support, and educational interventions.

PURPOSE

Theoretical, methodological, and practical strategies are needed to expand current biosocial methods for nursing science and focus on upstream, structural determinants of health and the policies that underlie health inequities.

METHODS

This paper summarizes presentations given at the 2023 Council for the Advancement of Nursing Science Advanced Methods Conference, Biosocial Methods to Advance Health Equity, in a panel titled "Individual, community, systems and policy related to biosocial methods."

DISCUSSION

Nurses are uniquely positioned to examine upstream, structural determinants of health by leveraging expertise in biosocial methods, collaborating with interdisciplinary researchers and community members, and advocating for policy change. By conducting theory-grounded biosocial research, nurse researchers can significantly advance scientific knowledge and promote health equity for individuals and communities.

CONCLUSION

Nurse scientists are conducting research using biosocial methods and provide recommendations for expansion of this approach in the field.

The association between unintended hysterotomy extensions with cesarean delivery and subsequent preterm birth

BACKGROUND

An increased risk for preterm birth has been observed among individuals with a previous second stage cesarean delivery when compared with those with a previous vaginal delivery. One mechanism that may contribute to the increased risk for preterm birth following a second stage cesarean delivery is the increased risk for cervical injury because of extension of the uterine incision (hysterotomy) into the cervix. The contribution of hysterotomy extension to the rate of preterm birth in a subsequent pregnancy has not been investigated and may shed light on the mechanism underlying the observed relationship between the mode of delivery and subsequent preterm birth.

OBJECTIVE

We aimed to quantify the association between unintended hysterotomy extension and preterm birth in a subsequent delivery.

STUDY DESIGN

We performed a retrospective cohort study using electronic perinatal data collected from 2 university-affiliated obstetrical centers. The study included patients with a primary cesarean delivery of a term, singleton live birth and a subsequent singleton birth in the same catchment (2005-2021). The primary outcome was subsequent preterm birth <37 weeks' gestation; secondary outcomes included subsequent preterm birth at <34, <32, and <28 weeks' gestation. We assessed crude and adjusted associations between unintended hysterotomy extensions and subsequent preterm birth with log binomial regression models using rate ratios and 95% confidence intervals. Adjusted models included several characteristics of the primary cesarean delivery such as maternal age, length of active labor, indication for cesarean delivery, chorioamnionitis, and maternal comorbidity.

RESULTS

A total 4797 patients met the study inclusion criteria. The overall rate of unintended hysterotomy extension in the primary cesarean delivery was 6.0% and the total rate of preterm birth in the subsequent pregnancy was 4.8%. Patients with an unintended hysterotomy extension were more likely to have a longer duration of active labor, chorioamnionitis, failed vacuum delivery attempt, second stage cesarean delivery, and persistent occiput posterior position of the fetal head in the primary cesarean delivery and higher rates of smoking in the subsequent pregnancy. Multivariable analyses that controlled for several confounders showed that a history of hysterotomy extension was not associated with a higher risk for preterm birth <37 weeks' gestation (adjusted rate ratio, 1.55; 95% confidence interval, 0.98-2.47), but it was associated with preterm birth <34 weeks' gestation (adjusted rate ratio, 2.49; 95% confidence interval, 1.06-5.42).

CONCLUSION

Patients with a uterine incision extension have a 2.5 times higher rate of preterm birth <34 weeks' gestation when compared with patients who did not have this injury. This association was not observed for preterm birth <37 weeks' gestation. Future research should aim to replicate our analyses with incorporation of additional data to minimize the potential for residual confounding.

Changes of uterocervical angle and cervical length in early and mid-pregnancy and their value in predicting spontaneous preterm birth

Objective: To explore the feasibility of transvaginal ultrasound measurement of uterocervical angle (UCA) and cervical length (CL) in early and mid-pregnancy and evaluate their combined prediction of spontaneous preterm birth (sPTB) in singleton pregnancies. Patients and Methods: This retrospective study comprised 274 pregnant women who underwent transvaginal ultrasound measurement of CL in mid-pregnancy (15-23+6 weeks); in 75 among them, CL also had been measured in early-pregnancy (<14 weeks). These 274 pregnant women were further divided into a preterm group (n = 149, <37 weeks gestation) and a control group (n = 125, >37 weeks gestation) according to delivery before or after 37 weeks, respectively. In the preterm group, 35 patients delivered before 34 weeks and the remaining 114 delivered between 34 and 37 weeks. Results: The optimal threshold of CL to predict preterm birth risk in women with <37 weeks gestation was 3.38 cm, and the optimal threshold of the UCA to predict preterm birth risk in the same group of women was 96°. The optimal threshold of CL to predict preterm birth risk in women with <34 weeks gestation was 2.54 cm, while that of the UCA in the same group of patients was 106°. The area under the curve for predicting preterm birth by combining the UCA and CL measurements was greater than that by using the UCA or CL alone (p < 0.01). The sensitivity and specificity for predicting preterm birth at <34 weeks gestation was 71.7% and 86.4%, respectively; and the sensitivity and specificity for predicting preterm birth at <37 weeks gestation was 87.6% and 80.6%, respectively. The difference between the two groups in CL and UCA were not significant in early pregnancy (p > 0.01), but only in mid-pregnancy (p < 0.01). There was a negative correlation between UCA and gestational week at delivery (r = -0.361, p < 0.001) and a positive correlation between CL and gestational week at delivery (r = 0.346, p < 0.001) in mid-pregnancy. The proportion of deliveries at <34 weeks was highest when the UCA was >105°, and the proportion of deliveries between 35 and 37 weeks was highest when the UCA was between 95° and 105°. The proportion of deliveries at <34 weeks was highest when the CL was <2.5 cm. Conclusion: The combination of UCA and CL has a better ability to predict preterm birth than either measurement alone. A more obtuse UCA or a shorter CL is associated with an earlier spontaneous preterm birth. The UCA increases from early to mid-pregnancy, while the CL decreases from early to mid-pregnancy.

Missing Black males among preterm births in the US, 1995 to 2019

BACKGROUND

In the US, non-Hispanic (NH) Black birthing persons show a two-fold greater risk of fetal death relative to NH white birthing persons. Since males more than females show a greater risk of fetal death, such loss in utero may affect the sex composition of live births born preterm (PTB; <37 weeks gestational age). We examine US birth data from 1995 to 2019 to determine whether the ratio of male to female preterm (i.e., PTB sex ratios) among NH Black births falls below that of NH whites and Hispanics.

METHODS

We acquired data on all live births in the US from January 1995 to December 2019. We arrayed 63 million live births into 293 "conception cohort" months of which 2,475,928 NH Black, 5,746,953 NH white, and 2,511,450 Hispanic infants were PTB. We used linear regression methods to identify trend and seasonal patterns in PTB sex ratios. We also examined subgroup differences in PTB sex ratios (e.g., advanced maternal ages, twin gestations, and narrower gestational age ranges).

RESULTS

The mean PTB sex ratio for NH Black births over the entire test period (1.06, 95% Confidence Interval [CI]: 1.05, 1.07) is much lower than that for NH white births (1.18, 95% CI: 1.17, 1.19). NH Black PTB sex ratios are especially low for twins and for births to mothers 35 years or older. Only NH white PTB sex ratios show a trend over the test period.

CONCLUSIONS

Analysis of over 10 million PTBs reveals a persistently low male PTB frequency among NH Black conception cohorts relative to NH white cohorts. Low PTB sex ratios among NH Black births concentrate among subgroups that show an elevated risk of fetal death. PTB sex ratios may serve as an indicator of racial/ethnic and subgroup differences in fetal death, especially among male gestations.

Anaphylaxis-induced premature uterine contractions: a case report and literature review

BACKGROUND

Preterm labor is caused by multiple etiologies, including intra-amniotic infection and/or intra-amniotic inflammation, vascular disorders, cervical disease, decidual senescence, and breakdown of maternal-fetal tolerance. Accumulating evidence in vivo and in vitro has shown that an allergic reaction, including anaphylaxis, can induce preterm uterine contractions. This report describes a case of a pregnant woman who developed anaphylaxis and regular uterine contractions after the ingestion of a strawberry-coated biscuit. We also review the mechanism of allergic reaction (hypersensitivity)-induced preterm labor. Case presentation A 31-year-old woman (gravida 1, para 0) at 30+2 weeks of gestation was admitted to the labor and delivery unit with regular uterine contractions and anaphylactic symptoms after she ingested a strawberry-coated biscuit as a snack. The uterine contractions resolved after the treatment of anaphylaxis by administering antihistamines and epinephrine. The patient subsequently delivered at 39+3 weeks of gestation. The amniotic fluid profile showed no infection or inflammation. A postpartum skin-prick test confirmed a positive type 1 hypersensitivity reaction to the strawberry-coated biscuit.

CONCLUSIONS

We report a case of anaphylaxis-induced uterine contractility in which uterine contractions subsided after the treatment of anaphylaxis. The absence of intra-amniotic infection and/or intra-amniotic inflammation and the cause of the anaphylaxis were confirmed. Our findings indicate that maternal allergic reactions may be one of the mechanisms of preterm labor.

Preterm births prevalence during the COVID-19 pandemic in Brazil: results from the national database

The SARS-CoV-2 (COVID-19) pandemic impacted the health systems between and within countries, and in the course of the pandemic sexual and reproductive health services were the most disrupted. Findings from high-income settings have reported significant changes in preterm birth prevalence during the pandemic period. To understand the possible effects of the COVID-19 pandemic on preterm birth numbers at the Brazilian national level. We compare the number of preterm deliveries during the COVID-19 pandemic period (2020 and 2021) with previous years. We conducted a population-based cross-sectional study taking the period from January 2017 to December 2021 to account. We use individual-level live births data from the Brazilian Live Birth Information System (SINASC), and we estimate the odds ratio (OR) of preterm deliveries using propensity score weighting analysis in Brazil and its regions. During the study period (from 2017 to 2021), about 2.7 million live births were recorded per year, and the missing value for gestational age at delivery was less than 1.5%. The preterm birth prevalence slightly increased during the COVID-19 pandemic compared to the pre-pandemic period (11.32% in 2021 vs 11.09% in 2019, p-value < 0.0001). After adjusting for sociodemographic variables, the OR of preterm births in Brazil has significantly increased, 4% in 2020 (OR: 1.04 [1.03-1.05] 95% CI, p-value < 0.001), and 2% in 2021(OR: 1.02 [1.01-1.03] 95% CI, p-value < 0.001), compared to 2019. At the regional level, the preterm birth pattern in the South, Southeast and Northeast regions show a similar pattern. The highest odds ratio was observed in the South region (2020 vs 2019, OR: 1.07 [1.05-1.10] 95% CI; 2021 vs 2019, OR: 1.03 [1.01-1.06] 95% CI). However, we also observed a significant reduction in the ORs of preterm births in the northern region during the COVID-19 pandemic (2020 vs 2019, OR: 0.96 [0.94-0.98] 95% CI) and (2021 vs 2019, OR: 0.97 [0.95-0.99] 95% CI). Our analysis shows that the pandemic has increased regional variation in the number of preterm births in Brazil in 2020 and 2021 compared to the pre-pandemic years.

Neonatal outcomes of preterm neonates and its predictors in Ethiopian public hospitals: Multicenter prospective follow-up study

Introduction

Preterm birth remains the most significant clinical and public health encounter. Preterm infant outcomes pose key evidence for clinicians and policymakers and are extensively used to set clinical and policy verdicts to improve services. It is necessary to conduct the outcomes of neonates frequently, as it varies from place to place and even from time to time in a similar place. There is limited literature in Ethiopia about preterm neonates' outcomes and their predictors.

Objective

This study aimed to assess the neonatal outcomes of preterm neonates and their predictors in South Gondar zone public hospitals, Northwest Ethiopia, 2021.

Methods

A prospective observational study was employed on 462 preterm neonates in South Gondar Zone Public Hospitals. The data were entered into Epidata 4.6 and analyzed using STATA version 16/MP software. A parametric log-normal survival model was used to identify possible predictors for preterm neonate death. Statistical significance was declared at a P-value less than 0.05.

Result

The overall preterm survival rate was 71.1% (95% CI: 66.7, 75.1). Thirty-six percent of preterm neonates were diagnosed with sepsis. One-fourth of the neonates had respiratory distress syndrome. Gestational age greater than 34 weeks (β = 1.04; 95% CI: 0.53, 1.56), respiratory distress syndrome (β = 0.85; 95% CI: 0.49, 1.22), body mass index (β = -1.34; 95% CI: -1.87, -0.80), non-union marital status (β = -0.71; 95% CI: -1.34, -0.09), multiple pregnancies (β = -0.66; 95% CI: -0.99-0.32), multiparous (β = 0.35; 95% CI: 0.01, 0.69), hypothermia (β = -1.19; 95% CI: -1.76, -0.62), Kangaroo Mother Care (β = -1.9; 95% CI: -2.34, -1.41) and non-cephalic presentation (β = -1.23; 95% CI: -1.99,-0.46) were significant predictors.

Conclusion

In this study, the preterm survival rate was low. Gestational age greater than 34 weeks, no respiratory distress syndrome, and multiparous mothers were positively associated with the survival of preterm neonates. Though, high pre-pregnancy maternal body mass index, non-union marital status of mothers, multiple pregnancies, hypothermia, Kangaroo mother care is not given, and non-cephalic presentation were negatively associated. A significant focus should be given to implementing WHO recommendations on preventing and caring for preterm births.

Amniotic Sludge and Prematurity: Systematic Review and Meta-analysis

OBJECTIVE

 To perform a systematic review and meta-analysis of studies on maternal, fetal, and neonatal outcomes of women with singleton pregnancies, after spontaneous conception, and with the diagnosis of amniotic sludge before 37 weeks of gestational age.

DATA SOURCES

 We conducted a search on the PubMed, Cochrane, Bireme, and Theses databases until June 2022.

SELECTION OF STUDIES

 Using the keywords intra-amniotic sludge or fluid sludge or echogenic particles, we found 263 articles, 132 of which were duplicates, and 70 were discarded because they did not meet the inclusion criteria.

DATA COLLECTION

 The articles retrieved were analyzed by 2 reviewers; 61 were selected for full-text analysis, 18 were included for a qualitative analysis, and 14, for a quantitative analysis.

DATA SYNTHESIS

 Among the maternal outcomes analyzed, there was an increased risk of preterm labor (95% confidence interval [95%CI]: 1.45-2.03), premature rupture of ovular membranes (95%CI: 1.99-3.79), and clinical (95%CI: 1.41-6.19) and histological chorioamnionitis (95%CI: 1.75-3.12). Regarding the fetal outcomes, there was a significant increase in the risk of morbidity (95%CI: 1.80-3.17), mortality (95%CI: 1.14-18.57), admission to the Neonatal Intensive Care Unit (NICU; 95%CI: 1.17-1.95), and neonatal sepsis (95%CI: 2.29-7.55).

CONCLUSION

 The results of the present study indicate that the presence of amniotic sludge is a risk marker for preterm delivery. Despite the heterogeneity of the studies analyzed, even in patients with other risk factors for prematurity, such as short cervix and previous preterm delivery, the presence of amniotic sludge increases the risk of premature labor. Moreover, antibiotic therapy seems to be a treatment for amniotic sludge, and it may prolong pregnancy.

A Matter of the Heart: Why It Is Time to Change How We Talk About Maternal Mortality

As the global burden of disease shifts from "diseases of poverty" such as diarrhea to "diseases of affluence" like diabetes and heart disease, a parallel shift is underway in maternal health. Maternal death from hemorrhage is decreasing, while deaths resulting from exacerbation of underlying chronic disease are on the rise.

Third trimester as the susceptibility window for maternal PM2.5 exposure and preterm birth: A nationwide surveillance-based association study in China

Maternal PM_2.5 exposure has been identified as a potential risk factor for preterm birth, yet the inconsistent findings on the susceptible exposure windows may be partially due to the influence of gaseous pollutants. This study aims to examine the association between PM_2.5 exposure and preterm birth during different susceptible exposure windows after adjusting for exposure to gaseous pollutants. We collected 2,294,188 records of singleton live births from 30 provinces of China from 2013 to 2019, and the gridded daily concentrations of air pollutants (including PM_2.5, O₃, NO₂, SO₂, and CO) were derived by using machine learning models for assessing individual exposure. We employed logistic regression to develop single-pollutant models (including PM_2.5 only) and co-pollutant models (including PM_2.5 and a gaseous pollutant) to estimate the odds ratio for preterm birth and its subtypes, with adjustment for maternal age, neonatal sex, parity, meteorological conditions, and other potential confounders. In the single-pollutant models, PM_2.5 exposure in each trimester was significantly associated with preterm birth, and the third trimester exposure showed a stronger association with very preterm birth than that with moderate to late preterm birth. The co-pollutant models revealed that preterm birth might be significantly associated only with maternal exposure to PM_2.5 in the third trimester, and not with exposure in the first or second trimester. The observed significant associations between preterm birth and maternal PM_2.5 exposure in the first and second trimesters in single-pollutant models might primarily be influenced by exposure to gaseous pollutants. Our study provides evidence that the third trimester may be the susceptible window for maternal PM_2.5 exposure and preterm birth. The association between PM_2.5 exposure and preterm birth could be influenced by gaseous pollutants, which should be taken into consideration when evaluating the impact of PM_2.5 exposure on maternal and fetal health.

Analysing heart rate variability in preterm infants: the effect of temporal adjustment of NN peaks and missing data

The measurement of heart rate variability (HRV) in preterm infants provides important information on function to clinicians. Measuring the underlying electrocardiogram (ECG) in the neonatal intensive care unit is a challenge and there is a trade off between extracting accurate measurements of the HRV and the amount of ECG processed due to contamination. Knowledge on the effects of 1) quantization in the time domain and 2) missing data on the calculation of HRV features will inform clinical implementation. In this paper, we studied multiple 5 minute epochs from 148 ECG recordings on 56 extremely preterm infants. We found that temporal adjustment of NN peaks improves the estimate of the NN interval resulting in HRV features (m = 9) that are better correlated with age (median percentage increase in correlation of individual features: 0.2%, IQR: 0.0 to 5.6%; correlation with age predictor and age from 0.721 to 0.787). Improved (sub-sample) quantization of the NN intervals (via interpolation) reduced the overall value of HRV features (median percentage reduction in feature value: -1.3%, IQR: -18.8 to 0.0; m = 9), primarily through a reduction in the energy of high-frequency oscillations. HRV features were also robust to missing data, with measures such as mean NN, fractal dimension and the smoothed nonlinear energy operator (SNEO) less susceptible to missing data than features such as VLF, LF, and HF. Furthermore, age predictions derived from a combination of HRV measures were more robust to missing data than individual HRV measures.Clinical Relevance-Poor quantization in time when estimating the NN peak and the presence of missing data confound HRV measures, particularly spectral measures.

Association between Parity and Preterm Birth-Retrospective Analysis from a Single Center in Poland

Preterm births and parity are two medical areas that seem to be entirely different from each other. The aim of this study was to analyze the relationships between parity and maternal and neonatal outcomes associated with preterm birth. This study involved a retrospective analysis of electronic medical records from St. Sophia Hospital in Warsaw (Poland). This study was conducted among women who gave birth to preterm infants between 1 January 2017 and 31 December 2021. A total of 2043 cases of preterm births were included in the final analysis. A higher odds ratio of preterm birth in primiparas was found in women living in a city/town (OR = 1.56) and having secondary (OR = 1.46) and higher education (OR = 1.82). Multiparas who gave birth to preterm infants were more frequently diagnosed with gestational diabetes (19.69%) than primiparas. Multiparas were more likely to give birth to preterm infants who received an Apgar score of ≤7 both at 1 and 5 min after birth (25.80% and 15.34%). The results of our study emphasize the differences between primiparas and multiparas who give birth to preterm infants. Knowledge of these differences is essential to improve the perinatal care provided to mothers and their infants.

An evaluation of the association between lockdown during the SARS-CoV-2 pandemic and prematurity at the Nice University Hospital

Aim

To study the association between lockdown in France due to the SARS-CoV-2 pandemic and premature births at the Nice University Hospital.

Methods

Data concerning neonates born at the level III maternity of the Nice University Hospital and immediately hospitalised in the neonatal reanimation unit or the neonatology department of the hospital with their mothers between the 1st of January 2017 and the 31st of December 2020, included.

Results

We did not find a significant decrease in the global number of premature births <37 weeks of gestation, in low weight at birth or a significant increase in stillbirths during lockdown compared to a period with no lockdown. The profiles of the mothers and their newborns were compared when birth occurred during lockdown vs. no lockdown.

Conclusion

We did not find any evidence of an association between lockdown and prematurity at the Nice University Hospital. This result is in agreement with meta-analyses published in the medical literature. The possible decrease in factors of risk of prematurity during lockdown is controversial.

Distribution of uterocervical angles of pregnant women at 16+ 0 to 23+ 6 weeks gestation with low risk for preterm birth: first vietnamese cohort of women with singleton pregnancies

BACKGROUND

Cervical length (CL) measured by ultrasound in the second trimester is a predictor of spontaneous preterm birth (sPTB). The uterocervical angle (UCA) has recently been suggested as a predictor to identify women at risk of sPTB. The aim of this study was to investigate the UCAs' distribution in singleton pregnant women at 16^+ 0 - 23^+ 6 weeks of gestation with low risk for sPTB.

METHODS

This was a prospective cohort study of 1,051 pregnant women with singleton pregnancies at low risk for preterm delivery. Pregnant women with a viable singleton fetus at 16^+ 0 - 23^+ 6 weeks of gestation were enrolled in the study conducted at the Haiphong Hospital of Obstetrics and Gynecology, Vietnam, from 09/2019 to 09/2020. CL and the UCA were assessed using transvaginal ultrasonography (TVS) by a single sonographer. Subjects were followed-up until the end of pregnancy, and maternal and neonatal outcomes were recorded. The UCAs' range and their relationship with gestational age were evaluated using regression analysis. P < 0.05 was considered statistically significant.

RESULTS

The normal range of the UCA (5^th - 95^th percentiles) was 46.47° (95% CI, 40.27°-51.81°) to 127.06° (95% CI, 123.02° - 130.71°). The UCAs in the preterm birth (< 37 weeks) and full-term groups were 117.86° ± 20.25° and 83.80° ± 24.18°, respectively (p < 0.001). Linear regression analysis showed a significant change in the UCA range from 16^+ 0 to 23^+ 6 weeks of gestation (2.51 degrees per week, p < 0.001). The linear function yielded the highest correlation coefficient in the variation rule of the UCA values (r = 0.22). A total of 42/63 (66.7%) patients with preterm birth < 37 weeks had a UCA above the 75^th percentile. The majority of women with preterm birth had a UCA ≥ 95° compared with those with full-term delivery (88.9% vs. 31.3%, p < 0.001).

CONCLUSIONS

The results of this study present background information about the normal range of UCA values in singleton pregnant women at 16^+ 0 to 23^+ 6 weeks at low risk for sPTB in this Vietnamese cohort. In this study population at low risk for sPTB, pregnant women with a UCA value ≥ 95^o were also considered at risk for preterm birth.

Causes, survival rates, and short-term outcomes of preterm births in a tertiary hospital in a low resource setting: An observational cohort study

Background

Prematurity is the most important cause of death among children under the age of five years. Globally, most preterm births occur in Sub-Saharan Africa. Subsequent prematurity leads to significant neonatal morbidity, mortality and long-term disabilities. This study aimed to determine the causes, survival rates and outcomes of preterm births up to six weeks of corrected age in Ghana.

Materials and methods

An observational prospective cohort study of infants born preterm was conducted in a tertiary hospital in Accra, Ghana from August 2019 to March 2020. Inclusion was performed within 48 h after birth of surviving infants; multiple pregnancies and stillbirths were excluded. Causes of preterm birth were categorized as spontaneous (including preterm pre-labour rupture of membranes) or provider-initiated (medically indicated birth based on maternal or fetal indications). Survival rates and adverse outcomes were assessed at six weeks of corrected age. Recruitment and follow-up were suspended due to the COVID-19 outbreak. Descriptive statistics and differences between determinants were calculated using Chi-squared tests or Kruskal-Wallis test.

Results

Of the 758 preterm deliveries, 654 (86.3%) infants were born alive. 179 were enrolled in the cohort and were analyzed. Nine (5%) were extremely preterm [gestational age (GA) < 28 weeks], 40 (22%) very preterm (GA 28-31 weeks), and 130 (73%) moderate to late preterm (GA 32-37 weeks) births. Most deliveries (n = 116, 65%) were provider-initiated, often due to hypertensive disorders in pregnancy (n = 79, 44.1%). Sixty-two infants were followed-up out of which fifty-two survived, presenting a survival rate of 84% (n = 52/62) at six weeks corrected age in this group. Most infants (90%, n = 47/52) experienced complications, predominantly consisted of NICU admission (92%) and interval illnesses (21%) including jaundice and sepsis.

Conclusions

The incidence of adverse outcomes associated with preterm birth in a tertiary facility with NICU capacity is high. Larger longitudinal studies are needed for an in-depth understanding of the causes and longer-term outcomes of preterm birth, and to identify effective strategies to improve outcomes in resource constrained settings.

Adherence to recommended physical activity restrictions due to threatened preterm delivery - a descriptive multi-center study

BACKGROUND

Threatened preterm delivery is a serious obstetrical complication and has for decades been prescribed physical activity restrictions (AR). Adherence to the recommended level of physical AR is however unknown. This study aimed to assess the objectively measured different physical positions and activities of pregnant women recommended AR due to threatened preterm delivery complications, compared to a reference group of uncomplicated pregnant women without restrictions, and to explore if admission status influenced adherence to AR.

METHODS

A Danish descriptive, clinical multi-center study included singleton pregnancies between 22-33 gestational weeks admitted to an antenatal ward or during midwife consultations either prescribed AR due to threatened preterm delivery or uncomplicated controls without restrictions. For seven days participants wore two tri-axial accelerometric SENS® monitors. Accelerometric data included time spent in five different positions, activities, and step counts. At inclusion demographic and obstetric information was collected.

RESULTS

Seventy-two pregnant women participated; 31% were prescribed strict AR, 15% moderate, 3% light, 8% unspecified, and 43% had no AR. Strict AR participants rested in the supine/lateral position for 17.7 median hours/day (range:9.6-24.0); sat upright 4.9 h/day (0.11-11.7); took 1,520steps/day (20-5,482), and 64% were inpatients. Moderate AR participants rested in the supine/lateral position for 15.1 h/day (11.5-21.6); sat upright 5.6 h/day (2.0-9.3); took 3,310steps/day (467-6,968), and 64% were outpatients. Participants with no AR rested 10.5 h/day (6.3-15.4) in supine/lateral position; sat upright 7.6 h/day (0.1-11.4) and took 9,235steps/day (3,225-20,818). Compared to no restrictions, participants with strict or moderate AR spent significant more time in physical resting positions and took significant fewer mean steps. Among strict AR admission status did not alter time spent in the physical positions, nor the step count.

CONCLUSIONS

Overall, participants adhered highly to the recommended AR. However, discriminating between strict and moderate AR recommendations did not alter how physical resting positions and activities were carried out. The admission status did not influence how participants adhered to strict AR.

Effect of preoperative low-normal cervical length on perinatal outcome after laparotomy-assisted fetoscopic spina bifida repair

OBJECTIVE

To determine if preoperative cervical length in the low-normal range increases the risk of adverse perinatal outcome in patients undergoing fetoscopic spina bifida repair.

METHODS

This was a retrospective cohort study of patients who underwent fetal spina bifida repair between September 2014 and May 2022 at a single center. Cervical length was measured on transvaginal ultrasound during the week before surgery. Eligibility for laparotomy-assisted fetoscopic spina bifida repair was as per the criteria of the Management of Myelomeningocele Study, although maternal body mass index (BMI) up to 40 kg/m² was allowed. Laparotomy-assisted fetoscopic spina bifida repair was performed, with carbon dioxide insufflation via two 12-French ports in the exteriorized uterus. All patients received the same peri- and postoperative tocolysis regimen, including magnesium sulfate, nifedipine and indomethacin. Postoperative follow-up ultrasound scans were performed either weekly (< 32 weeks' gestation) or twice a week (≥ 32 weeks). Perinatal outcome was compared between patients with a preoperative cervical length of 25-30 mm vs those with a cervical length > 30 mm. Logistic regression analyses and generalized linear mixed regression analyses were used to predict delivery at less than 30, 34 and 37 weeks' gestation.

RESULTS

The study included 99 patients with a preoperative cervical length > 30 mm and 12 patients with a cervix 25-30 mm in length. One further case which underwent spina bifida repair was excluded because cervical length was measured > 1 week before surgery. No differences in maternal demographics, gestational age (GA) at surgery, duration of surgery or duration of carbon dioxide uterine insufflation were observed between groups. Cases with low-normal cervical length had an earlier GA at delivery (median (range), 35.2 (25.1-39.7) weeks vs 38.2 (26.0-40.9) weeks; P = 0.01), higher rates of delivery at < 34 weeks (41.7% vs 10.2%; P = 0.01) and < 30 weeks (25.0% vs 1.0%; P < 0.01) and a higher rate of preterm prelabor rupture of membranes (PPROM) (58.3% vs 26.3%; P = 0.04) at an earlier GA (mean ± SD, 29.3 ± 4.0 weeks vs 33.0 ± 2.4 weeks; P = 0.05) compared to those with a normal cervical length. Neonates of cases with low-normal cervical length had a longer stay in the neonatal intensive care unit (20 (7-162) days vs 9 (3-253) days; P = 0.02) and higher rates of respiratory distress syndrome (50.0% vs 14.4%; P < 0.01), sepsis (16.7% vs 1.0%; P = 0.03), necrotizing enterocolitis (16.7% vs 0%; P = 0.01) and retinopathy (33.3% vs 1.0%; P < 0.01). There was an association between preoperative cervical length and risk of delivery at < 30 weeks which was significant only for patients with a maternal BMI < 25 kg/m² (odds ratio, 0.37 (95% CI, 0.07-0.81); P = 0.02).

CONCLUSIONS

Low-normal cervical length (25-30 mm) as measured before in-utero laparotomy-assisted fetoscopic spina bifida repair may increase the risk of adverse perinatal outcomes, including PPROM and preterm birth, leading to higher rates of neonatal complications. These data warrant further research and are of critical relevance for clinical teams considering the eligibility of patients for in-utero spina bifida repair. Based on this evidence, patients with a low-normal cervical length should be aware of their increased risk for adverse perinatal outcome. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Does a cervical pessary reduce the rate of preterm birth in women with a short cervix?

OBJECTIVES

To evaluate neonatal outcomes after the use of a cervical pessary in Japanese women with short cervical length (CL) less than 25 mm.

METHODS

This multicenter study involved women with singleton pregnancies between 20 and 29+6 gestational weeks and a CL of less than 25 mm. The primary outcome was preterm birth (PTB) before 34 weeks of gestation. This study was registered in the Japan Registry of Clinical Trials (JRCT: jRCTs042180102).

RESULTS

Two hundred pregnant women were enrolled; 114 in the pessary group and 86 in the expectant management group as controls. In the pessary group, all 114 neonates were investigated for perinatal outcomes, and 112 pregnant women were investigated for primary, and secondary outcomes. In the control group, 86 pregnant women were investigated for primary and secondary outcomes and 86 neonates were investigated for neonatal outcomes. There were no significant differences in PTB in ≤34, ≤37, and ≤28 weeks of gestation or in preterm rupture of membranes (PROM) ≤34 weeks between the groups. The gestational weeks at birth and birth weight were significantly higher in the pessary group. Regression analysis demonstrated that the CL decreased without a pessary, whereas the shortening rate was suppressed during the intervention. No significant differences were observed in adverse neonatal outcomes, chorioamnionitis, or preterm PROM.

CONCLUSIONS

The cervical pessary effectively reduced CL shortening during pregnancy resulting in an average increased gestational age, however, did not reduced the rates of preterm birth.

Cervical pessary and cerclage placement for preterm birth prevention and cervicovaginal microbiome changes

INTRODUCTION

Our objective was to compare the vaginal microbiome in low-risk and high-risk pregnant women and to explore a potential association between vaginal microbiome and preterm birth.

MATERIAL AND METHODS

A pilot, consecutive, longitudinal, multicenter study was conducted in pregnant women at 18-22 weeks of gestation. Participants were assigned to one of three groups: control (normal cervix), pessary (cervical length ≤25 mm) and cerclage (cervical length ≤25 mm or history of preterm birth). Analysis and comparison of vaginal microbiota as a primary outcome was performed at inclusion and at 30 weeks of gestation, along with a follow-up of pregnancy and perinatal outcomes. We assessed the vaginal microbiome of pregnant women presenting a short cervix with that of pregnant women having a normal cervix, and compared the vaginal microbiome of women with a short cervix before and after placement of a cervical pessary or a cervical cerclage.

RESULTS

The microbiome of our control cohort was dominated by Lactobacillus crispatus and inners. Five community state types were identified and microbiome diversity did not change significantly over 10 weeks in controls. On the other hand, a short cervix was associated with a lower microbial load and higher microbial richness, and was not correlated with Lactobacillus relative abundance. After intervention, the cerclage group (n = 19) had a significant increase in microbial richness and a shift towards community state types driven by various bacterial species, including Lactobacillus mulieris, unidentified Bifidobacterium or Enterococcus. These changes were not significantly observed in the pessary (n = 26) and control (n = 35) groups. The cerclage group had more threatened preterm labor episodes and poorer outcomes than the control and pessary groups.

CONCLUSIONS

These findings indicate that a short cervix is associated with an altered vaginal microbiome community structure. The use of a cerclage for preterm birth prevention, as compared with a pessary, was associated with a microbial community harboring a relatively low abundance of Lactobacillus, with more threatened preterm labor episodes, and with poorer clinical outcomes.

Interrupted-time-series analysis of the immediate impact of COVID-19 mitigation measures on preterm birth in China

Preliminary evidence from China and other countries has suggested that coronavirus disease 2019 (COVID-19) mitigation measures have caused a decline in preterm births, but evidence is conflicting. Utilising a national representative data of 11,714,947 pregnant women in China, we explored the immediate changes in preterm birth rates during the COVID-19 mitigation period using an interrupted-time-series analysis. We defined the period prior to February 1, 2020 as the baseline, followed by the COVID-19 mitigation stage. In the first month of the COVID-19 mitigation, a significant absolute decrease in preterm birth rates of 0.68% (95%CI:−1.10% to −0.26%) in singleton, and of 2.80% (95%CI:−4.51% to −1.09%) in multiple births was noted. This immediate decline in Wuhan was greater than that at the national level among singleton births [−2.21% (95%CI:−4.09% to −0.34% vs. −0.68%)]. Here we report an immediate impact of COVID-19 mitigation measures on preterm birth in China.

The broader impacts of COVID-19 mitigation measures may include changes in the incidence of preterm birth. Here, the authors use data from ~11.7 million pregnancies in China and find evidence of a small decline in preterm birth rates immediately following the implementation of COVID-19 mitigation measures.

The Association between the Burden of PM2.5-Related Neonatal Preterm Birth and Socio-Demographic Index from 1990 to 2019: A Global Burden Study

BACKGROUND

Preterm birth (PTB) leads to short-term and long-term adverse effects on newborns. Exposure to fine particulate matter (PM_2.5) was positively related to PTB. However, the global annual average PM_2.5 was three times than the recommended value in 1998-2014. Socio-demographic index (SDI) is a new indicator that comprehensively reflects the overall development level of a country, partly because of "the epidemiological transition". Among other countries with higher and similar SDI levels, policy makers have the opportunity to learn from their successful experiences and avoid their mistakes by identifying whether their burdens of disease are higher or lower than the expected. However, it is unclear about the trends of the burden of PM_2.5-related preterm birth in different countries and different levels of SDI regions. Additionally, the relationship between the SDI and the burden in 1990-2019 is also unclear.

METHODS

This was a retrospective study based on the Global Burden of Disease Study 2019 (GBD2019) database from 1990 to 2019. The burden of PM_2.5-related PTB was measured by the age-standardized mortality rate (ASMR), age-standardized disability-adjusted life years rate (ASDR), mortality rate, and the disability-adjusted life years (DALYs). The annual percentage changes (APCs) and the average annual percentage changes (AAPCs) were used to reflect the trends over the past 30 years, which were calculated using a joinpoint model. The relationships between the ASMR, ASDR, and SDI were calculated using a Gaussian process regression.

FINDINGS

In 2019, the entire burden of PM_2.5-related PTB was relatively high, where the ASMR and the ASDR were 0.76 and 67.71, increasing by 7.04% and 7.12%, respectively. It mainly concentrated on early neonates, boys, and on low-middle SDI regions. The increase in the burden of PM_2.5-related PTB in low and low-middle SDI regions is slightly higher than the decrease in other SDI regions. In 2019, the burden varied greatly among different levels of SDI regions where ASMRs varied from 0.13 in high SDI regions to 1.19 in low-middle regions. The relationship between the expected value of the burden of PM_2.5-related PTB and SDI presented an inverted U-shape, and it reached the maximum when SDI is around 0.50. The burdens in four regions (South Asia, North Africa and the Middle East, western sub-Saharan Africa, and southern sub-Saharan Africa) were much higher than the mean value. Boys bore more burden that girls. The sex ratio (boys:girls) of the burden showed a dramatically increasing trend in low SDI regions and a decreasing trend in middle SDI regions and high-middle SDI regions. These differences reflect the huge inequality among regions, countries, ages, and sex in the burden of PM_2.5-related PTB.

CONCLUSION

The overall burden of PM_2.5-related PTB in 2019 was relatively high, mainly concentrated on early neonates, boys, and on low-middle SDI regions. It showed an increasing trend in low-middle and low SDI regions. The association between the burden and the SDI presented an inverted U-shape. It is very necessary to promulgate policies to prevent and control air pollution in countries with large and increasing exposure to PM_2.5 pollution because it does not need action at an individual level. Focusing on public educational interventions, public and professional policies, and improving accessibility of prenatal care are other feasible ways for low and low-middle SDI countries. Policy makers should also appropriately allocate medical resources to boys and early newborns.

Determinants of preterm birth: proposal for a hierarchical theoretical model

Abstract Preterm birth (PB) is a syndrome resulting from a complex relationship between multiple factors which do not have fully understood relationships and causality. This article discusses a hierarchical theoretical model of PB determinants, considering maternal characteristics such as sociodemographic, psychosocial, nutritional, behavioral and biological aspects, traditionally associated with increased risk of PB. The variables were distributed in six dimensions within three hierarchical levels (distal, intermediate and proximal). In this model, the socioeconomic determinants of the mother, family, household and neighborhood play indirect effects on PB through variables at the intermediate level, which in turn affect biological risk factors at the proximal level that have a direct effect on PB. The study presents a hierarchical theoretical model of the factors involved in the PB determination chain and their interrelationships. Understanding these interrelationships is an important step in trying to break the causal chain that makes some women vulnerable to preterm birth.

Determinants of preterm birth: proposal for a hierarchical theoretical model

Preterm birth (PB) is a syndrome resulting from a complex relationship between multiple factors which do not have fully understood relationships and causality. This article discusses a hierarchical theoretical model of PB determinants, considering maternal characteristics such as sociodemographic, psychosocial, nutritional, behavioral and biological aspects, traditionally associated with increased risk of PB. The variables were distributed in six dimensions within three hierarchical levels (distal, intermediate and proximal). In this model, the socioeconomic determinants of the mother, family, household and neighborhood play indirect effects on PB through variables at the intermediate level, which in turn affect biological risk factors at the proximal level that have a direct effect on PB. The study presents a hierarchical theoretical model of the factors involved in the PB determination chain and their interrelationships. Understanding these interrelationships is an important step in trying to break the causal chain that makes some women vulnerable to preterm birth.

Efficacy of Antenatal Magnesium Sulfate for Neuroprotection in Extreme Prematurity: A Comparative Observational Study

Background

Survival of preterm infants has improved drastically. In addition to significant contribution to neonatal mortality, impact of prematurity among survivors may continue through life impairing long-term physical life through neuro-disability and increased risk of cerebral palsy. Maternal administration of magnesium sulfate prior to impending preterm birth is an effective strategy to reduce neuromorbidity.

Aim

To investigate the effectiveness of antenatal magnesium sulfate for neuroprotection in preterm infants between 26 and 34 weeks in preventing early neonatal morbidity and mortality. Secondary objective was to assess any adverse events with the use of magnesium sulfate on the mother and neonate.

Method

This was a prospective observational comparative study for 2 years at our tertiary care hospital of 100 pregnant women who gave preterm births. Fifty infants each were born to mothers who were either not given MgSO4 (Group 1) or given 4gm intravenous loading dose MgSO4 (Group 2), preferably 4 h prior to preterm birth.

Results

Among all the preterm in our study, 81% delivered between 30 and 34 weeks. There was no significant difference in terms of maternal mortality or serious morbidity including postpartum hemorrhage, caesarian section rates or length of hospital stay among women receiving MgSO4 versus no MgSO4. Mild maternal side effects secondary to magnesium sulfate were experienced in 8% cases. There were no significant differences between both groups for low 5 min APGAR, need for NICU admission, neonatal convulsions, hyperbilirubinemia, necrotizing enterocolitis, periventricular leukomalacia and septicemia. There was a trend toward reduced risk in the magnesium sulfate group for need for mechanical ventilation and ongoing respiratory support, intraventricular hemorrhage, neonatal hypotension, hypothermia, length of NICU stay. IVH was less frequent and less severe in babies exposed to antenatal MgSO4 (8%) as compared to non-MgSO4 group (16%). Neonatal morbidities were more when antenatal MgSO4 was given less than 4 h from delivery.

Conclusion

MgSO4 is a safe drug to use in antenatal women at risk for impending preterm. Antenatal magnesium sulfate given to women in established preterm labor conferred significant neuroprotective advantage to the neonate. MgSO4 also has protective effect on the need of invasive ventilatory support in preterm infants. Given the breadth of evidence in its favor, it is time for us to start using MgSO4 in clinical practice for neuroprotective intent in all our extreme preterm births.

Does Maternal Obesity Affect Preterm Birth? Documentary Cohort Study of Preterm in Firstborns—Silesia (Poland)

In addition to low birth weight and intrauterine growth restriction, prematurity is a major problem in modern neonatology. The etiology of premature delivery is multifactorial, but maternal obesity has been indicated as an important risk factor for preterm birth. This study aimed to assess the relationship between early pregnancy body mass index (BMI) and the risk of preterm delivery according to gestational age. In the cohort of 2794 firstborns, preterm deliveries accounted for 9.1%. Of all deliveries, 16, 48, and 189 were classified as extremely preterm, very preterm, and moderately preterm deliveries, respectively. The risk of extremely, very, and moderately preterm deliveries increased with the increasing BMI, with the highest overweight and obesity-related risk for extremely and very preterm delivery. The rate of extremely and very preterm delivery among normal-weight women (BMI 18.5 ≤ 25) was 1.8%, while that among overweight and obese women (BMI ≥ 25) was 2.36%. The rate of all preterm deliveries (22 ≤ 37 weeks) was 8% for normal-weight women and 10.3% for overweight and obese women. Compared with normal-weight women, the adjusted odds ratio (95% CI) for preterm delivery in overweight and obese women was 1.33 (0.98–1.79). In Poland, being overweight and obese during pregnancy was associated with an increased risk of preterm delivery, especially extremely and very preterm delivery. This relationship should be assessed in other populations.

Effect of maternal thallium exposure in early pregnancy on the risk of preterm birth

Human activities have significantly increased the release of thallium (Tl) to the environment. However, the study of the relationship between maternal Tl exposure during pregnancy and the risk of preterm birth (PTB) is scarce so far. We aimed to investigate the association between Tl exposure in early pregnancy and the risk of PTB. A total of 2104 pregnant women from the Tongji Maternal and Child Health Cohort (TMCHC) in Wuhan, China were enrolled in the analysis. We collected the urine samples in early pregnancy (< 20 weeks) and inductively coupled plasma mass spectrometry (ICP-MS) was used to detect urinary Tl levels. The association between Tl levels and the risk of PTB was evaluated by an unconditional logistic regression. The median and geometric mean values of Tl levels were 0.35 μg/L (0.47 μg/g creatinine) and 0.33 μg/L (0.47 μg/g creatinine), respectively. Compared with the lowest tertile of Tl levels (≤ 0.37 μg/g creatinine), the highest tertile (> 0.57 μg/g creatinine) was associated with an increased risk of PTB with an adjusted odds ratio (OR) of 2.11 (95% confidence interval (CI): 1.08, 4.12). Stratified analyses showed an elevated risk of PTB related to the highest tertile of Tl levels for male newborns. After excluding women with miss covariate information, gestational diabetes mellitus, pregnancy-induced hypertension, reporting fish intake, or exposed to smoke, the association remained stable. Our results suggested that maternal Tl exposure during early pregnancy was positively associated with the risk of PTB, and Tl exposure may have a sex-specific effect on PTB.

Geographical disparities in infant mortality in the rural areas of China: a descriptive study, 2010-2018

BACKGROUND

The infant mortality rate (IMR) is considered a basic measure of public health for countries around the world. The specific aim of our study was to provide an updated description of infant mortality rate among different regions in rural China, and assess the trends and causes of the IMR geographical disparities.

METHODS

Data were collected from China's Under-5 Child Mortality Surveillance System(U5CMSS). The annual number of deaths and causes of death were adjusted using a 3-year moving average underreporting rate based on annual national data quality control results. The average annual decline rate (AADR) and the relative risk (RR) of the IMR and cause-specific infant mortality were calculated by Poisson regression and the Cochran-Mantel-Haenszel method. Data analysis was completed by SAS software.

RESULTS

There was an apparent decrease in infant mortality in rural China from 2010 to 2018, at the AADR of 11.0% (95%CI 9.6-12.4), 11.2% (95%CI 10.3-12.1) and 6.6% (95%CI 6.0-7.3) in the eastern, central and western rural areas, respectively. The IMR was highest in the western rural area, followed by the central and eastern rural areas. Compared with the eastern rural area, the RR of infant mortality in the central rural area remained at 1.4-1.6 and increased from 2.4 (95%CI 2.3-2.6) in 2010-2012 to 3.1 (95% CI 2.9-3.4) in 2016-2018 in the western rural area. Pneumonia, preterm birth /LBW and birth asphyxia were the leading causes of infant deaths in the western rural area. Mortality rates of these three causes fell significantly in 2010-2018 but contributed to a higher proportion of deaths in the western rural area than in the central and western rural ares.

CONCLUSIONS

Our study indicated that the infant mortality rate dropped significantly from 2010 to 2018, however, geographical disparities of IMR in rural China are still persist. Therefore, there is an urgent need for public health programmes and policy interventions for infants in western rural China.

Associations between early marriage and preterm delivery: Evidence from lowland Nepal

OBJECTIVES

Preterm delivery (<37 weeks gestation) is the largest cause of child mortality worldwide. Marriage and pregnancy during adolescence have been associated with an increased risk of preterm delivery. We investigate independent associations of age at marriage and age at first pregnancy with preterm delivery in a cohort of women from rural lowland Nepal.

METHODS

We analyzed data from 17 974 women in the Low Birth Weight South Asia Trial. Logistic regression models tested associations of age at marriage and age at first pregnancy with preterm delivery, for primigravida (n = 6 243) and multigravida (n = 11 731) women. Models were adjusted for maternal education, maternal caste, and household asset score.

RESULTS

Ninety percent of participants had married at <18 years and 58% had their first pregnancy at <18 years. 20% of participants delivered preterm. Primigravida participants married at ≤14 years had higher odds of preterm delivery than those married ≥18 years, when adjusting for study design (adjusted odds ratio (aOR) 1.45, 95% CI: 1.15-1.83), confounders (aOR 1.28: 1.01-1.62) and confounders + age at pregnancy (aOR 1.29: 1.00-1.68). Associations were insignificant for multigravida women. No significant associations were observed between age at first pregnancy and preterm delivery.

DISCUSSION

In this population, early marriage, rather than pregnancy, is a risk factor for preterm delivery. We hypothesize that psychological stress, a driver of preterm delivery which is increased among those marrying young, rather than physiological immaturity, drives this association. Further research into the psychological consequences of child marriage in Nepal is needed.

A randomized controlled trial of two-doses of vaginal progesterone 400 vs. 200 mg for prevention of preterm labor in twin gestations

OBJECTIVES

To compare between the effectiveness and safety of two different daily doses of vaginal progesterone (400 vs. 200 mg) in the prevention of preterm labor in twin pregnancy.

METHODS

This is a prospective single-blinded randomized controlled trial conducted on 100 primi-gravida who had twin pregnancy and attended the antenatal clinic of a University hospital. They were equally and randomly allocated into two arms each containing 50 patients. Arm 1 received 400 mg and arm 2 received 200 mg vaginal progesterone daily at bed time starting from 14 weeks of pregnancy to 36 weeks. Transvaginal ultrasound was performed for assessment of the length of cervix at 14 and 22 weeks.

RESULTS

Both arms of the current study were comparable regarding the cervical length at 14 and 22 weeks, mean gestational age at delivery, incidence of pre-term delivery, birth weight of the first twin. Second twin in addition to the average weight of both twins. No statistical significance differences between two arms regarding incidence of early neonatal death. NICU, mechanical ventilation, length of admission in NICU for the first twin. Second twin as well as both twins.

CONCLUSIONS

Vaginal progesterone treatment with different doses was tolerable, but wasn't effective in the prevention of preterm labor in twin pregnancy.

First trimester HtrA1 maternal plasma level and spontaneous preterm birth

OBJECTIVES

High temperature requirement A1 (HtrA1) is a serine protease detected in maternal plasma and in placental tissues during normal gestation and in various pathological conditions. The purpose of this study was to determine whether the maternal plasma concentration of HtrA1 in first trimester, alone or combined with other maternal factors, can be used to identify women at risk for spontaneous preterm birth (SPTB).

STUDY DESIGN

This is a cohort study on pregnant women at 12 weeks of gestation recruited between 2014 and 2016 and prospectively followed until delivery. One hundred and fifty-nine women were included in the study: 140 women delivered at term and 19 (11.9%) delivered spontaneously preterm. Plasma samples were assessed for HtrA1 by ELISA and data were compared between women which delivered at term with women which delivered preterm. A multiple logistic regression analysis was used to estimate the independent effect of women's characteristics on the probability of a SPTB.

RESULTS

SPTB was significantly associated with log HtrA1 values at 12 weeks of gestation, BMI before pregnancy and physical activity. In particular, the probability of a SPTB increases of 79% for every added unit of log HtrA1, while decreases of 18% for every added unit of BMI. In addition, physical activity was found as an important protective factor. The ROC curve showed that the model had a good accuracy in predicting SPTB, with an AUC equal to 0.83 (95%CI: 0.73-0.91).

CONCLUSIONS

Maternal plasma HtrA1 may be considered a marker of SPTB. In addition, our model indicates two factors that could be modified to reduce the risk of SPTB, i.e. BMI before pregnancy and maternal physical activity.

The selective progesterone receptor modulator-promegestone-delays term parturition and prevents systemic inflammation-mediated preterm birth in mice

BACKGROUND

Progesterone, acting via its nuclear receptors called progesterone receptors, promotes myometrial relaxation during pregnancy, and suspension of this activity triggers labor. We previously found that 20α-hydroxysteroid dehydrogenase causes a local withdrawal of progesterone in the term and preterm myometrium by converting the progesterone into an inactive form before it accesses the progesterone receptors.

OBJECTIVE

We hypothesized that a selective progesterone receptor modulator called promegestone, which is not metabolized by 20α-hydroxysteroid dehydrogenase, would sustain progesterone receptor signaling and prevent/delay term labor and preterm labor in mice.

STUDY DESIGN

In the term labor mouse model, promegestone (0.2 mg/dam) or a vehicle were administered subcutaneously in timed-pregnant CD-1 mice at gestational days 15, 16, and 17 (term gestational days, 19.5). In the inflammation preterm labor model, pregnant mice received promegestone or a vehicle on gestational days 15, 16, and 17, which was 24 hours before, immediately before, and 24 hours after systemic bacterial endotoxin (50 μg intraperitoneal; lipopolysaccharide group) or vehicle (saline) administration. The maternal and fetal tissues were collected on gestational day 16 6 hours after lipopolysaccharide±promegestone injection and at term gestational day 18.75. The protein levels of 10 cytokines were measured by multiplex immunoassay in maternal plasma and amniotic fluid. Myometrial, decidual, and placental messenger RNA levels of multiple cytokines and procontractile proteins were evaluated by real-time polymerase chain reaction and confirmed by immunoblotting.

RESULTS

Promegestone prevented term labor and maintained mice pregnancy postterm >24 hours. The litter size and fetal weights were not different from the controls. Promegestone prevented systemic bacterial-endotoxin-induced preterm labor in 100% of the mice, blocked uterine contractions, significantly inhibited all systemic inflammation-induced myometrial cytokines, and partially inhibited decidual and placental inflammation. Promegestone did not prevent bacterial-endotoxin-induced fetal toxicity.

CONCLUSION

Promegestone a selective progesterone receptor modulator that binds progesterone receptors with high affinity and is not metabolized by 20α-hydroxysteroid dehydrogenase could completely suppress term parturition and systemic bacterial-endotoxin-induced preterm birth in mice. We suggest that such selective progesterone receptor modulators may represent a potential therapeutic approach to the prevention of preterm labor in women at high risk of preterm birth.

Short information: Bacterial meningitis in very low birthweight infants in Korea from 2013-2016

BACKGROUND

Neonatal bacterial meningitis (BM) has an incidence of 0.2-0.4 per 1,000 births and a mortality rate of 20-25%. Data from the Korean Neonatal Network (KNN) were evaluated to study the incidence, mortality, and risk factors associated with BM in very-low-birthweight (VLBW; <1,500 g) infants.

METHODS

We analyzed KNN data from 2013-2016 collected from 70 neonatal units.

RESULTS

The incidence of BM in VLBW infants was 40 out of 8,263 (0.5%). The 40 infants with BM had a mean gestational age of 27.1 ± 2.0 weeks and a mean birthweight of 1,036.8 ± 220.0 g. Mean age at diagnosis was 51.5 ± 38.3 days (range, 1-171). Infants with BM were divided into two groups: Group 1 (onset age ≤ 28 days) and Group 2 (onset age > 28 days). Coagulase-negative Staphylococcus (CONS) was the most common pathogen underlying meningitis in 11 of 40 cases (28%). BM co-occurred with bacteremia in 14 of 40) of cases (35%); bacteremia was significantly more common in Group 1 than Group 2 (P < 0.05). Seizure and intraventricular hemorrhage (≥grade 3) were significantly more prevalent in Group 2 than Group 1 (P < 0.05). The mortality rate of infants with BM was 4 out of 40 (10%), which was significantly lower than that of VLBW infants without BM (1,152/8,223, [14%]; P < 0.05).

CONCLUSIONS

The incidence of BM in VLBW infants was high, but the mortality rate was low. CONS was the most common pathogen of BM in VLBW infants.

Preterm neonatal mortality in China during 2009-2018: A retrospective study

In this retrospective analysis, we aimed to analyze the epidemic characteristics of neonatal mortality due to preterm birth at 28-36 weeks gestation in different regions from 2009 to 2018. Data were obtained from China's Under-5 Child Mortality Surveillance System (U5CMSS). The χ2 trend test, Poisson regression and the Cochran-Mantel-Haenszel method were used in this study. We found that 51.3%, 42.0% and 44.5% of neonate deaths were preterm infants, and immaturity was mainly attributed to 60.1%, 64.1% and 69.5% of these deaths, in the eastern, central and western regions, respectively. The preterm neonatal mortality rate due to immaturity dropped from 149.2, 216.5 and 339.5 in 2009 to 47.4, 83.8 and 170.1 per 100 000 live births in 2018, giving an average annual decline rate of 12.1%, 11.6% and 6.3% in the eastern, central and western regions, respectively, during the studying period. The relative risk of preterm neonatal mortality due to immaturity were 1.3 and 2.3 for the central regions and western regions in 2009-2010, ascending to 2.2 and 3.9 in 2017-2018. The proportion of preterm neonatal deaths with a gestational age <32 weeks was highest among the eastern region. There were significantly more preterm neonatal infants who were not delivered at medical institutions in the western region than in the eastern and central regions. The preterm infant, especially with gestational age <32 weeks, should receive the most attention through enhanced policies and programs to improve child survival. Priority interventions should be region-specific, depending on the availability of economic and healthcare resources.

Effectiveness of cervical pessary in women with arrested preterm labor compared to those with asymptomatic cervical shortening

OBJECTIVE

To determine whether the effectiveness of cervical pessary is different in women who experienced cervical shortening after a threatened preterm labor episode compared to those with asymptomatic short cervix.

METHODS

Retrospective study on singleton pregnancies at risk for preterm delivery (PTD) due to cervical length <25 mm before 28 weeks, who were treated with Arabin cervical pessary. Two groups of patients were compared: those who had contractions causing shortening of the cervix, prior to pessary placement, and those who had asymptomatic cervical shortening. Patients carrying a multiple pregnancy and those who underwent iatrogenic PTD were excluded. The primary outcome was the incidence of PTD at different gestational ages. Secondary outcome was the rate of preterm premature rupture of membrane (pPROM). The groups were compared using univariate and multivariate analyses.

RESULTS

115 patients that met the inclusion criteria were identified. Of these, 91 (79%) had asymptomatic cervical shortening, while 24 (21%) had an episode of threatened preterm labor that resolved, and the pessary was placed after the contractions had stopped. The two groups were similar for maternal characteristics, obstetric history, mean gestational age and length of the cervix at the time of pessary insertion. The median gestational age at delivery was significantly lower (36.4 vs 38.0 weeks, p = .02), and the incidence of PTD significantly higher (58.3% vs 30.8%, OR 4.69, 95% CI 1.68-13.1, p < .01) among women who had arrested preterm labor before the pessary was placed compared to the asymptomatic group, after controlling for confounders. The incidence of PTD before 34 and before 32 weeks was also significantly higher in the symptomatic group (p = .02 and p = .005, respectively). Women with asymptomatic cervical shortening had a longer interval between the placement of the pessary and delivery (median 15 weeks). pPROM occurred with a similar incidence in both groups.

CONCLUSIONS

Arabin cervical pessary to prevent preterm delivery seems be less effective in women with a short cervix following an episode of threatened preterm labor than in those with asymptomatic cervical shortening in the second trimester. This finding may help physicians to select patients in which cervical pessary is more likely to be effective, and to improve patient's counseling about this intervention.

Preterm birth among Pacific Islander women and related perinatal outcomes: a scoping review protocol

INTRODUCTION

Infants born alive <37 weeks are classified as premature. The global estimate of preterm birth in 2014 was 10.6%, and it is the leading cause of death of children under the age of 5 years. Preterm birth disproportionately affects women of minority populations, yet knowledge about the incidence and associated outcomes among Pacific Islanders is limited. The objectives of this scoping review are to identify studies that describe risk factors, maternal-child health outcomes and existing interventions to prevent preterm birth among Pacific Islanders, and to summarise the barriers and facilitators to decrease the burden.

METHODS AND ANALYSIS

We will follow the Joanna Briggs Institute Manual for Evidence Synthesis for scoping reviews and the Preferred Reporting Items for Scoping Reviews (PRISMA-ScR) to conduct this scoping review. The Covidence web application will be used for data management and consensus review. We will search on MEDLINE ALL (Ovid), EMBASE (Ovid), Web of Science Core Collection (as licensed at Yale), the Cochrane Library, CINAHL (EBSCOhost) and two non-indexed regional journals (Pacific Journal of Reproductive Health and Pacific Health Dialog). Title-abstract and full-text screening of eligible studies will be performed by two authors, and data will be extracted by the first author. Outcomes extracted will be presented using evidence mapping.

ETHICS AND DISSEMINATION

Findings will drive suggestions for new data collection needed to fill knowledge gaps and improve future study designs to decrease the burden of preterm birth among Pacific Islanders. There are no ethical concerns. This protocol will be disseminated in related peer-reviewed journals.

Risk factors and clinical characteristics for bronchopulmonary dysplasia associated pulmonary hypertension in very-low-birth-weight infants

BACKGROUND

Pulmonary hypertension (PH) is a common complication of bronchopulmonary dysplasia (BPD) in very-low-birth-weight infants (VLBWIs). Although recent studies have increased awareness that PH contributes significantly to the high morbidity and mortality of BPD, the risk factors and clinical characteristics for PH in VLBWIs are little known.

OBJECTIVES

To investigate the risk factors and clinical characteristics for BPD-associated pulmonary hypertension (BPD-PH) in VLBWIs.

METHODS

A retrospective case-control observational study of VLBWIs with BPD admitted to a neonatal intensive care unit (NICU) over 4 years. According to echocardiograms confirming elevated pulmonary artery pressure after 28 days after birth, we divided BPD infants into PH group (n = 18) and non-PH group (n = 65). We compared pre- and postnatal characteristics between VLBWIs with or without PH. Multivariable logistic regression analysis was conducted with backward selection.

RESULTS

A total of 83 infants with BPD were divided into PH group (n = 18) or non-PH group (n = 65). The average birth weight of the infants with BPD was 1078.1 g. Compared with those infants of the non-PH group, the birth weight of BPD-PH infants was significantly lower (968.1 ± 187.7 vs. 1108.5 ± 185.8, P = 0.006). Infants in the PH group had a higher incidence of patent ductus arteriosus (PDA) and underwent longer durations of oxygen therapy and mechanical ventilation compared to those in the non-PH group. In all subjects, birth weight (OR 0.995; 95% CI 0.991-0.999; P = 0.025) and PDA (OR 13.355; 95% CI 2.950-60.469; P = 0.001) were found to be specific risk factors for BPD-PH in this cohort.

CONCLUSIONS

The study shows PDA and birth weight are specific risk factors for BPD-PH in VLBWIs.

FIGO good practice recommendations on magnesium sulfate administration for preterm fetal neuroprotection

In women at risk of early preterm imminent birth, from viability to 30 weeks of gestation, use of MgSO4 for neuroprotection of the fetus is recommended. In pregnancies below 32–34 weeks of gestation, the use of MgSO4 for neuroprotection of the fetus should be considered. MgSO4 should be administered regardless of the cause for preterm birth and the number of babies in utero. MgSO4 should be administered when early preterm birth is planned or expected within 24 h. When birth is planned, MgSO4 should commence as close as possible to 4 h before birth. If delivery is planned or expected to occur sooner than 4 h, MgSO4 should be administered, as there is still likely to be an advantage from administration within this time. The optimal regimen of MgSO4 for fetal neuroprotection is an intravenous loading dose of 4 g (administered slowly over 20–30 min), followed by a 1 g per hour maintenance dose. This regimen should continue until birth but should be stopped after 24 h if undelivered. When MgSO4 is administered, women should be monitored for clinical signs of magnesium toxicity at least every 4 h by recording pulse, blood pressure, respiratory rate, and deep tendon (for example, patellar) reflexes.

MgSO4 for fetal neuroprotection is recommended to women at risk of imminent preterm birth below 30 weeks of gestation.

Weekly 17 alpha-hydroxyprogesterone caproate to prevent preterm birth among women living with HIV: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Women with HIV face an increased risk of preterm birth. 17 alpha-hydroxyprogesterone caproate (17P) has been shown in some trials to reduce early delivery among women with a history of spontaneous preterm birth. We investigated whether 17P would reduce this risk among women with HIV.

METHODS

We did a randomised, double-blind, placebo-controlled trial in pregnant women with HIV at the University Teaching Hospital and Kamwala District Health Centre in Lusaka, Zambia. Eligible patients were women aged 18 years or older with confirmed HIV-1 infection, viable intrauterine singleton pregnancy at less than 24 weeks of gestation, and were receiving or intending to commence antiretroviral therapy during pregnancy. Exclusion criteria were major uterine or fetal anomaly; planned or in situ cervical cerclage; evidence of threatened miscarriage, preterm labour, or ruptured membranes at screening; medical contraindication to 17P; previous participation in the trial; or history of spontaneous preterm birth. Eligible participants provided written informed consent and were randomly assigned (1:1) to receive 250 mg intramuscular 17P or placebo once per week, starting between 16 and 24 weeks of gestation until delivery, stillbirth, or reaching term (37 weeks). Participants and study staff were masked to assignment, except for pharmacy staff who did random assignment and prepared injections but did not interact with participants. The primary outcome was a composite of delivery before 37 weeks or stillbirth at any gestational age. Patients attended weekly visits for study drug injections and antenatal care. We estimated the absolute and relative difference in risk of the primary outcome and safety events between treatment groups by intention to treat. This trial is registered with ClinicalTrials.gov, NCT03297216, and is complete.

FINDINGS

Between Feb 7, 2018 and Jan 13, 2020, we assessed 1042 women for inclusion into the study. 242 women were excluded after additional assessments, and 800 eligible patients were enrolled and randomly assigned to receive intramuscular 17P (n=399) or placebo (n=401). Baseline characteristics were similar between groups. Adherence to study drug injections was 98% in both groups, no patients were lost to follow-up, and the final post-partum visit was on Aug 6, 2020. 36 (9%) of 399 participants assigned to 17P had preterm birth or stillbirth, compared with 36 (9%) of 401 patients assigned to placebo (risk difference 0·1, 95% CI -3·9 to 4·0; relative risk 1·0, 95% CI 0·6 to 1·6; p=0·98). Intervention-related adverse events were reported by 140 (18%) of 800 participants and occurred in similar proportions in both randomisation groups. No serious adverse events were reported.

INTERPRETATION

Although 17P seems to be safe and acceptable to participants, available data do not support the use of the drug to prevent preterm birth among women whose risk derives solely from HIV infection. The low risk of preterm birth in both randomisation groups warrants further investigation.

FUNDING

US National Institutes of Health and the Bill and Melinda Gates Foundation.

Prediction of Spontaneous Preterm Birth in At-risk Women Using Thrombospondin 1 from Cervicovaginal Fluid: A Prospective Observational Study

Introduction Thrombospondin 1, desmoplakin and stratifin are putative biomarkers for the prediction of preterm birth. This study aimed to validate the predictive capability of these biomarkers in patients at risk of preterm birth.

Materials and Methods We included 109 women with symptoms of threatened spontaneous preterm birth between weeks 20 0/7 and 31 6/7 of gestation. Inclusion criteria were uterine contractions, cervical length of less than 25 mm, or a personal history of spontaneous preterm birth. Multiple gestations were also included. Samples of cervicovaginal fluid were taken before performing a digital examination and transvaginal ultrasound. Levels of cervicovaginal thrombospondin 1, desmoplakin and stratifin were quantified by enzyme-linked immunosorbent assays. The primary endpoint was spontaneous preterm birth before 34 + 0 weeks of gestation.

Results Sixteen women (14.7%) delivered before 34 + 0 weeks. Median levels of thrombospondin 1 were higher in samples where birth occurred before 34 weeks vs. ≥ 34 weeks of gestation (4904 vs. 469 pg/mL, p < 0.001). Receiver operator characteristics analysis resulted in an area under the curve of 0.86 (p < 0.0001). At an optimal cut-off value of 2163 pg/mL, sensitivity, specificity, positive predictive value and negative predictive value were 0.94, 0.77, 0.42 and 0.99, respectively, with an adjusted odds ratio of 32.9 (95% CI: 3.1 – 345, p = 0.004). Multiple gestation, cervical length, and preterm labor had no impact on the results. Survival analysis revealed a predictive period of more than eight weeks. Levels of desmoplakin and stratifin did not differ between groups.

Conclusion Thrombospondin 1 allowed long-term risk estimation of spontaneous preterm birth.

Associations Between Maternal Immunisation and Reduced Rates of Preterm Birth and Stillbirth: A Population Based Retrospective Cohort Study

Stillbirth and preterm birth (PTB) remain two of the most important, unresolved challenges in modern pregnancy care. Approximately 10% of all births are preterm with nearly one million children dying each year due to PTB. It remains the most common cause of death among children under five years of age. The numbers for stillbirth are no less shocking with 2.6 million babies stillborn each year. With minimal impact on the rate of these adverse birth outcomes over the past decade there is an urgent need to identify more effective interventions to tackle these problems. In this retrospective cohort study, we used whole-of-population data, to determine if maternal immunization during pregnancy against influenza and/or pertussis, is associated with a lower risk of PTB, delivering a small-for-gestational age (SGA) infant, developing preeclampsia or stillbirth. Women with a singleton pregnancy at 28 or more weeks' gestation delivering in Victoria, Australia from July 2015 to December 2018 were included in the analysis. Log-binomial regression was used to measure the relationship between vaccination during pregnancy against influenza and against pertussis, with preterm birth, SGA, preeclampsia and stillbirth. Variables included in the adjusted model were maternal age, body mass index, first or subsequent birth, maternal Indigenous status, socio-economic quintile, smoking, public or private maternity care and metropolitan or rural location of the hospital. Women who received influenza vaccine were 75% less likely to have a stillbirth (aRR 025; 95% CI 0.20, 0.31), and 31% less likely to birth <37 weeks (aRR 0.69; 95% CI 0.66, 0.72). Women who received pertussis vaccine were 77% less likely to have a stillbirth (aOR 0.23; 95% CI 0.18, 0.28) and 32% less likely to birth <37 weeks gestation (aRR 0.68; 95% CI 0.66, 0.71). Vaccination also reduced the odds of small for gestational age by 13% and reduced the odds of pre-eclampsia when restricted to primiparous women. This association was seen over four different influenza seasons and independent of the time of year suggesting that any protective effect on obstetric outcomes afforded by maternal vaccination may not be due to a pathogen-specific response but rather due to pathogen-agnostic immune-modulatory effects.

Explaining the Black-White Disparity in Preterm Birth: A Consensus Statement From a Multi-Disciplinary Scientific Work Group Convened by the March of Dimes

In 2017-2019, the March of Dimes convened a workgroup with biomedical, clinical, and epidemiologic expertise to review knowledge of the causes of the persistent Black-White disparity in preterm birth (PTB). Multiple databases were searched to identify hypothesized causes examined in peer-reviewed literature, 33 hypothesized causes were reviewed for whether they plausibly affect PTB and either occur more/less frequently and/or have a larger/smaller effect size among Black women vs. White women. While definitive proof is lacking for most potential causes, most are biologically plausible. No single downstream or midstream factor explains the disparity or its social patterning, however, many likely play limited roles, e.g., while genetic factors likely contribute to PTB, they explain at most a small fraction of the disparity. Research links most hypothesized midstream causes, including socioeconomic factors and stress, with the disparity through their influence on the hypothesized downstream factors. Socioeconomic factors alone cannot explain the disparity's social patterning. Chronic stress could affect PTB through neuroendocrine and immune mechanisms leading to inflammation and immune dysfunction, stress could alter a woman's microbiota, immune response to infection, chronic disease risks, and behaviors, and trigger epigenetic changes influencing PTB risk. As an upstream factor, racism in multiple forms has repeatedly been linked with the plausible midstream/downstream factors, including socioeconomic disadvantage, stress, and toxic exposures. Racism is the only factor identified that directly or indirectly could explain the racial disparities in the plausible midstream/downstream causes and the observed social patterning. Historical and contemporary systemic racism can explain the racial disparities in socioeconomic opportunities that differentially expose African Americans to lifelong financial stress and associated health-harming conditions. Segregation places Black women in stressful surroundings and exposes them to environmental hazards. Race-based discriminatory treatment is a pervasive stressor for Black women of all socioeconomic levels, considering both incidents and the constant vigilance needed to prepare oneself for potential incidents. Racism is a highly plausible, major upstream contributor to the Black-White disparity in PTB through multiple pathways and biological mechanisms. While much is unknown, existing knowledge and core values (equity, justice) support addressing racism in efforts to eliminate the racial disparity in PTB.