Prevention of preterm birth

Cervical length measurement between 11 and 13 + 6 weeks of pregnancy: Comparison of maternal and ultrasonographic characteristics between term and preterm deliveries

OBJECTIVE

The aim of this study was to evaluate the maternal and ultrasonographic characteristics of pregnant women who underwent cervical length (CL) measurement by transvaginal ultrasound between 11 and 13 + 6 weeks of gestation and who delivered at term or preterm.

METHODS

A retrospective cohort study was carried out between March 2013 and December 2018 by analyzing ultrasound data of singleton pregnant women who underwent CL measurement by transvaginal ultrasound during the first trimester scan. CL was compared between the two groups (full-term and preterm birth [PB]) using Student's t-test.

RESULTS

A total of 5097 pregnant women were enrolled, of whom 5061 (99.3%) had term and 36 (0.7%) had PB < 34 weeks. CL measurements did not differ between the term and preterm groups (36.62 vs. 37.83 mm, p = 0.08). Maternal age showed a significant and linear association with CL (r = 0.034, p = 0.012) and CRL (r = 0.086, p < 0.001). Smoking status was associated with shorter CL (36.64 vs. 35.09 mm, p = 0.003). When we analyzed the CL of the pregnant women in the term and preterm groups, according to the gestational age cut-offs for prematurity (28, 30, 32, and 34 weeks), we found that there was no significant difference between the measurements in all groups (p > 0.05).

CONCLUSION

We observed no significant differences between CL measurements between 11 and 13 + 6 weeks in pregnant women who had preterm and term deliveries. Gestational age and CRL showed a significant and linear association with CL measurement.

Pregnancy state before the onset of labor: a holistic mechanical perspective

Successful pregnancy highly depends on the complex interaction between the uterine body, cervix, and fetal membrane. This interaction is synchronized, usually following a specific sequence in normal vaginal deliveries: (1) cervical ripening, (2) uterine contractions, and (3) rupture of fetal membrane. The complex interaction between the cervix, fetal membrane, and uterine contractions before the onset of labor is investigated using a complete third-trimester gravid model of the uterus, cervix, fetal membrane, and abdomen. Through a series of numerical simulations, we investigate the mechanical impact of (i) initial cervical shape, (ii) cervical stiffness, (iii) cervical contractions, and (iv) intrauterine pressure. The findings of this work reveal several key observations: (i) maximum principal stress values in the cervix decrease in more dilated, shorter, and softer cervices; (ii) reduced cervical stiffness produces increased cervical dilation, larger cervical opening, and decreased cervical length; (iii) the initial cervical shape impacts final cervical dimensions; (iv) cervical contractions increase the maximum principal stress values and change the stress distributions; (v) cervical contractions potentiate cervical shortening and dilation; (vi) larger intrauterine pressure (IUP) causes considerably larger stress values and cervical opening, larger dilation, and smaller cervical length; and (vii) the biaxial strength of the fetal membrane is only surpassed in the cases of the (1) shortest and most dilated initial cervical geometry and (2) larger IUP.

Spillover effects of gestational age on sibling's literacy

Adverse health events within families can harm children's development, including their early literacy. Using data from a longitudinal Wisconsin birth cohort, we estimated the spillover effect of younger siblings' gestational ages on older siblings' kindergarten-level literacy. We sampled 20,014 sibling pairs born during 2007-2010 who took Phonological Awareness Literacy Screening-Kindergarten tests during 2012-2016. Exposures were gestational age (completed weeks), preterm birth (gestational age <37 weeks), and very preterm birth (gestational age <32 weeks). We used gain-score regression-a fixed effects strategy-to estimate spillover effect. A one-week increase in younger siblings' gestational age improved the older siblings' test score by 0.011 SD (95% confidence interval: 0.001, 0.021 SD). The estimated spillover effect was larger among siblings whose mothers reported having a high school diploma/equivalent only (0.024 SD; 95% CI: 0.004, 0.044 SD). The finding underscores the networked effects of one individual's early-life health shocks on their family members.

The association between preterm births and assisted reproductive technologies

AIMS

The aim of this study is to determine whether the risk of preterm births differs according to the conception method: with or without ART and according to the ART method used (in-vitro fertilisation (IVF) with fresh embryo transfer, frozen embryo transfer (FET) and oocyte receipt (OoR)).

METHODS

The research is based on individualised anonymised data on deliveries in Czechia in 2013-2018 (n=651,049) obtained from the National Health Information System. We employ the survival analysis approach applying survival functions (Life tables method) and Cox regression to model the risk of preterm births according to the conception method when controlling for a set of covariates.

RESULTS

The results revealed that the risk of preterm births in singleton pregnancies is higher for ART-treated women (1.56 to 2.06 depending on the ART method) than for non-ART-treated women. The proportion of preterm births differs according to the ART method; the highest proportion was observed for OoR mothers.

CONCLUSIONS

Overall, the differences between ART-treated mothers according to the conception method are due mainly to the structural differences between mothers. When controlling for the covariates (Cox regression model), no significant differences were observed concerning the risk of preterm births for women who underwent fresh IVF, FET and OoR.

Recurrent preterm birth: data from the study "Birth in Brazil"

OBJECTIVE

Describe and estimate the rate of recurrent preterm birth in Brazil according to the type of delivery, weighted by associated factors.

METHODS

We obtained data from the national hospital-based study "Birth in Brazil", conducted in 2011 and 2012, from interviews with 23,894 women. Initially, we used the chi-square test to verify the differences between newborns according to previous prematurity and type of recurrent prematurity. Sequentially, we applied the propensity score method to balance the groups according to the following covariates: maternal age, socio-economic status, smoking during pregnancy, parity, previous cesarean section, previous stillbirth or neonatal death, chronic hypertension and chronic diabetes. Finally, we performed multiple logistic regression to estimate the recorrence.

RESULTS

We analyzed 6,701 newborns. The rate of recurrence was 42.0%, considering all women with previous prematurity. Among the recurrent premature births, 62.2% were spontaneous and 37.8% were provider-initiated. After weighting by propensity score, we found that women with prematurity have 3.89 times the chance of having spontaneous recurrent preterm birth (ORaj = 3.89; 95%CI 3.01-5.03) and 3.47 times the chance of having provider-initiated recurrent preterm birth (ORaj = 3.47; 95%CI 2.59-4.66), compared to women who had full-term newborns.

CONCLUSIONS

Previous prematurity showed to be a strong predictor for its recurrence. Thus, expanding and improving the monitoring and management of pregnant women who had occurrence of prematurity strongly influence the reduction of rates and, consequently, the reduction of infant morbidity and mortality risks in the country.

Vancomycin-Resistant Enterococci and Extended-Spectrum β-Lactamase-Producing Bacterial Colonization of the Cervix after Emergency Cerclage: Is It Safe?

Antimicrobial resistance is currently becoming a global threat to human health. We performed a retrospective study on patients who underwent emergency cerclage between January 2016 and December 2018 at the Dongsan Medical Center. Cervical culture was first performed before surgery to confirm that there was no infection and was repeated on days 1, 4, and 7 after surgery. A total of 85 pregnant women underwent emergency cerclage. Among them, six patients had vancomycin-resistant enterococci (VRE) colonization in the cervix after cerclage, and 23 patients developed extended-spectrum β-lactamase (ESBL)-producing bacterial colonization in the cervix. The average gestational age at delivery was lower in the VRE group. Neonatal death was also significantly higher in the VRE group. The rate of occurrence of early-onset sepsis was also higher in the VRE group, and both VRE and ESBL-producing bacterial colonization cases in which early-onset sepsis occurred resulted in neonatal death. The prognosis of cervical VRE colonization after cervical surgery was poor, whereas the prognosis of ESBL-producing bacterial colonization in the cervix did not differ significantly from that of the control group. However, careful neonatal treatment is required considering that early-onset sepsis is fatal to the newborn.

Effect of maternal zinc supplementation or zinc status on pregnancy complications and perinatal outcomes: An umbrella review of meta-analyses

Zinc is an essential trace element involved in different physiological functions. During pregnancy, it plays a crucial role in healthy embryogenesis. This umbrella review, therefore, aimed to summarize the existing literature of meta-analyses evaluating the effect of maternal zinc supplementation or zinc status on maternal and neonatal outcomes. Two databases, PubMed and Scopus, were selected to search the available literature without any temporal restriction. The literature search was performed during October 2020 and a total of 192 records were identified through the literature search. After screening the titles and applying the inclusion/exclusion criteria, finally, 15 articles were included in this umbrella review. This umbrella review showed that maternal zinc supplements reduce the risk of preterm birth. Although no substantial effect of zinc supplements was found for other feto-maternal outcomes. Also, we found a significant relationship between low maternal zinc status and risk of pregnancy complications. Zinc supplements reduce the risk of preterm birth. Long-term interventions and cohort studies are needed for future research directions. Further studies and a thorough investigation will help to decide the recommended zinc dose or intake during pregnancy.

Critical analysis of electrohysterographic methods for continuous monitoring of intrauterine pressure

Monitoring the progression of uterine activity provides important prognostic information during pregnancy and delivery. Currently, uterine activity monitoring relies on direct or indirect mechanical measurements of intrauterine pressure (IUP), which are unsuitable for continuous long-term observation. The electrohysterogram (EHG) provides a non-invasive alternative to the existing methods and is suitable for long-term ambulatory use. Several published state-of-the-art methods for EHG-based IUP estimation are here discussed, analyzed, optimized, and compared. By means of parameter space exploration, key parameters of the methods are evaluated for their relevance and optimal values. We have optimized all methods towards higher IUP estimation accuracy and lower computational complexity. Their accuracy was compared with the gold standard accuracy of internally measured IUP. Their computational complexity was compared based on the required number of multiplications per second (MPS). Significant reductions in computational complexity have been obtained for all published algorithms, while improving IUP estimation accuracy. A correlation coefficient of 0.72 can be obtained using fewer than 120 MPS. We conclude that long-term ambulatory monitoring of uterine activity is possible using EHG-based methods. Furthermore, the choice of a base method for IUP estimation is less important than the correct selection of electrode positions, filter parameters, and postprocessing methods. The presented review of state-of-the-art methods and applied optimizations show that long-term ambulatory IUP monitoring is feasible using EHG measurements.

Transcriptomic analysis of fetal membranes reveals pathways involved in preterm birth

Background

Preterm birth (PTB), defined as infant delivery before 37 weeks of completed gestation, results from the interaction of both genetic and environmental components and constitutes a complex multifactorial syndrome. Transcriptome analysis of PTB has proven challenging because of the multiple causes of PTB and the numerous maternal and fetal gestational tissues that must interact to facilitate parturition. The transcriptome of the chorioamnion membranes at the site of rupture in PTB and term fetuses may reflect the molecular pathways of preterm labor.

Methods

In this work, chorioamnion membranes from severe preterm and term fetuses were analyzed using RNA sequencing. Functional annotations and pathway analysis of differentially expressed genes were performed with the GAGE and GOSeq packages. A subset of differentially expressed genes in PTB was validated in a larger cohort using qRT-PCR and by comparing our results with genes and pathways previously reported in the literature.

Results

A total of 270 genes were differentially expressed (DE): 252 were upregulated and 18 were down-regulated in severe preterm births relative to term births. Inflammatory and immunological pathways were upregulated in PTB. Both types of pathways were previously suggested to lead to PTB. Pathways that were not previously reported in PTB, such as the hemopoietic pathway, appeared upregulated in preterm membranes. A group of 18 downregulated genes discriminated between term and severe preterm cases. These genes potentially characterize a severe preterm transcriptome pattern and therefore are candidate genes for understanding the syndrome. Some of the downregulated genes are involved in the nervous system, morphogenesis (WNT1, DLX5, PAPPA2) and ion channel complexes (KCNJ16, KCNB1), making them good candidates as biomarkers of PTB.

Conclusions

The identification of this DE gene pattern will help with the development of a multi-gene disease classifier. These markers were generated in an admixed South American population in which PTB has a high incidence. Since the genetic background may differentially impact different populations, it is necessary to include populations such as those from South America and Africa, which are usually excluded from high-throughput approaches. These classifiers should be compared to those in other populations to obtain a global landscape of PTB.

Electronic supplementary material

The online version of this article (10.1186/s12920-019-0498-3) contains supplementary material, which is available to authorized users.

Research prioritization of interventions for the primary prevention of preterm birth: An international survey

OBJECTIVE

To identify research priorities of interventions for the primary prevention of preterm birth (PTB), by conducting an international stakeholder survey.

STUDY DESIGN

A prospective cross-sectional online survey was conducted in November 2016. Fifteen interventions to prevent spontaneous PTB were identified and ranked by stakeholders (n = 159) in the field of maternal and perinatal health research, using nine equally weighted criteria. Medians and interquartile ranges (IQRs) were calculated and the interventions ranked accordingly.

RESULTS

Respondents to the survey were from 46 different countries, mostly from low and middle-income countries (62%, 99/159) and were mainly clinicians (80%, 127/159). Of the fifteen interventions ranked, the following five were identified as research priorities in the primary prevention of PTB: dietary counselling and nutritional education, risk scoring, vitamin D supplementation, exercise and antioxidant supplementation.

CONCLUSION

We have identified research priorities of interventions to prevent spontaneous PTB through a global stakeholder survey. The interventions prioritized in this exercise can be used by researchers, grant funding bodies and research-policy decision makers to inform calls on future clinical trials or individual patient data meta-analyses on the primary prevention of PTB.

Identification of SMAD3 as a Novel Mediator of Inflammation in Human Myometrium In Vitro

Preterm birth remains the primary cause of early neonatal death and is a major determinant for long-term health consequences. Aberrant intrauterine inflammation and infection are known to augment the synthesis of proinflammatory cytokines and induce uterine contractions, which can subsequently lead to preterm birth. The transforming growth factor-β (TGF-β) superfamily members regulate numerous cellular processes through the activation of intracellular mediators known as mothers against decapentaplegic homolog (SMADs). Studies in nongestational tissues have shown that SMAD3 plays a role in immune regulation and inflammation; however, its role in human labour remains unknown. Thus, the present study aimed at (i) characterising the expression of SMAD3 in the human myometrium; (ii) determining the effect of bacterial and viral products and proinflammatory cytokines on SMAD3 transcriptional activity in primary human myometrial cells; and (iii) investigating the effect of SMAD3 siRNA knockdown on the production of prolabour mediators in primary human myometrial cells. Phosphorylated (i.e., active) SMAD3 protein expression was lower in the myometrium after spontaneous term labour compared to the myometrium from nonlabouring women. Using a luciferase assay, the proinflammatory cytokines IL-1β and TNF, and viral analogue polyinosinic : polycytidylic acid (poly(I : C)) significantly reduced SMAD3 transcriptional activity in human primary myometrial cells. Loss-of-function studies found that SMAD3 knockdown in myometrial cells significantly increased IL-1β- and poly(I : C)-induced proinflammatory cytokines (IL-1A, IL-6), chemokines (IL-8, MCP-1), the adhesion molecule ICAM-1, COX-2 mRNA expression, and subsequent PGF2α release. In conclusion, SMAD3 deficiency is associated with increased production of proinflammatory and prolabour mediators in the human myometrium.

Dental Caries and Developmental Defects of Enamel in the Primary Dentition of Preterm Infants: Case-Control Observational Study

AIM

Assessment of dental health in the primary dentition of preterm infants (PTI) including investigation of mother- and infant-related risk factors in a case-control study design.

MATERIAL AND METHODS

One hundred twenty-eight infants aged 3-4 years were included. Sixty-four PTI (27 males) were randomly selected from the preterm registry of the Jena University Hospital. As a control group served 64 full-term infants (FTI) recruited from the Department of Paediatric Dentistry, matched for age and sex. Dental examinations were provided by one dentist under standard clinical conditions. Caries was scored using the International Caries Detection and Assessment System (ICDAS II) and the DMFT, gingival health using the Periodontal Screening Index, and developmental defects of enamel using the DDE index. Mother- and infant-related factors were collected via a questionnaire and from medical records.

RESULTS

The caries prevalence was 50.0% (ICDAS II >0) in PTI and 12.5% (ICDAS II >0) in FTI. The caries experience was higher in PTI (DMFT 1.0 ± 3.1) than in FTI (DMFT 0.3 ± 1.0). PTI had a higher risk of caries (OR 7.0), initial lesions (OR 6.2), DDE (OR 7.5), and gingivitis (OR 6.5) than FTI. The highest risk occurred in PTI with an extremely low birth weight (<1,000 g). A higher risk of DDE was present when mothers suffered from illness during pregnancy (OR 3.9). A higher risk of caries was revealed in infants with respiratory syndrome (OR 6.2) or when their mothers had a lower socioeconomic status (OR 6.3).

CONCLUSIONS

PTI had less healthy teeth than FTI and are at a higher risk for DDE, caries, and gingivitis. The poorer dental health in PTI is associated with a low birth weight, a low socioeconomic status, and mothers' illness during pregnancy.

Optimal routes of administration, vehicles and timing of progesterone treatment for inhibition of delivery during pregnancy

OBJECTIVES

Progestins, notably progesterone (P4) and 17 alpha hydroxyprogesterone caproate, are presently used to treat pregnant women at risk of preterm birth. The aim of this study was to assess the optimal treatment options for progesterone (P4) to delay delivery using a sensitive bioassay for progesterone.

STUDY DESIGN

Pregnant rats, known to be highly sensitive to progestins, were treated with P4, including Prochieve^® (also known as Crinone^®), in various vehicles from day 13 of gestation and in late gestation, days 19 to 22, and delivery times noted. Various routes of administration of P4 and various treatment periods were studied.

RESULTS

Use of micronized P4 by rectal, subcutaneous injection (sc) and topical (transdermal) administration in various oils all significantly (P<0.05-<0.001) delay delivery, but vaginal Prochieve^® did not. Administration of P4 in late gestation also prevented (P<0.001) delivery even when given 8h before delivery.

CONCLUSIONS

Prochieve^® possesses little biological activity to suppress delivery in a sensitive bioassay system and suggests that this preparation may be of little value in prevention and inhibition of preterm birth. Further, this study shows: 1) Inhibition of delivery is increased with P4 treatments when given subcutaneously or topically. 2) P4 in fish oil provides the best vehicle for topical treatment and may be an effective treatment of preterm birth. 3) P4 in fish oil also delays delivery even when treatment begins just prior to normal delivery. 4) To prevent preterm birth in pregnant women, randomized controlled studies are needed with a potent progestin using better formulations and routes of administration.

Relationship of trimester-specific smoking patterns and risk of preterm birth

BACKGROUND

In 2011, the US national rate of smoking early in pregnancy was 11.5%. Unfortunately, our home state of Ohio had a rate twice as high at 23%. Smoking in pregnancy remains one of the most important modifiable risk factors for pregnancy complications, specifically preterm birth.

OBJECTIVE

The objective of the study was to quantify the preterm birth risk to various trimester-specific smoking behaviors.

STUDY DESIGN

The study was a population-based, retrospective cohort study of singleton non-anomalous live births, using Ohio birth records 2006 to 2012. Preterm birth rates were compared between non-smokers and women who smoked in the preconception period only, those who quit smoking after the 1st and 2nd trimesters, and those who smoked throughout pregnancy. Multivariate logistic regression quantified the risk of smoking with cessation at various times in pregnancy and preterm birth risk, adjusted for maternal race, education, age, Medicaid use, marital status, and parity. A stratified analysis was performed on the basis of preterm birth subtype: spontaneous preterm birth versus indicated preterm birth. We also performed an additional analysis stratifying for maternal race using the 2 largest categories of race (non-Hispanic white and non-Hispanic black).

RESULTS

Of the 913,757 birth records analyzed, nearly 25% of the women reported some smoking behavior on the birth certificate data. Of smokers, less than half quit during pregnancy (38.8% vs 61.2% smoked throughout pregnancy). Early quitters had a similar preterm birth rate compared with non-smokers. Women who smoked through the 1st trimester only did not have a significant increase in their overall preterm birth odds ratio <37 weeks; however, it did increase the odds of extreme preterm birth <28 weeks by 20% (adjusted odds ratio, 1.20; 95% confidence interval [CI], 1.02, 1.40). Quitting late in pregnancy resulted in the highest odds ratio increase: 70% for preterm birth <37 weeks (adjusted odds ratio 1.70; CI, 1.60, 1.80), even after adjustment for the confounding influences. Quitting smoking early in pregnancy after the 1st trimester did not increase the overall risk of spontaneous or indicated preterm birth <37 weeks significantly. However, quitting after the 1st trimester was associated with a significant increase in risk of extreme spontaneous preterm birth <28 weeks, an effect not seen with indicated preterm birth <28 weeks. Delaying cessation until late in pregnancy-after the 2nd trimester-was associated with the highest risk increases, 65% increased odds of spontaneous and 78% increase in odds of indicated preterm births. The rate of preterm births to non-Hispanic black mothers was increased in all categories over those of non-Hispanic white mothers. The relative influence of smoking cessation in pregnancy was similar in black compared with white mothers. The effect modification in the regression model was analyzed and revealed no significant interaction between race and smoking patterns on preterm birth risk.

CONCLUSION

Smoking throughout pregnancy is associated with an increased risk of preterm birth. However, quitting early in pregnancy negates this risk. Widespread programs aimed at smoking cessation early in pregnancy could have a significant impact on reducing the rate of preterm birth nationally.

Correlation Between Cervical Lengths Measured by Transabdominal and Transvaginal Sonography for Predicting Preterm Birth

OBJECTIVES

Cervical length assessment is important for predicting preterm birth. Cervical length measurement using transabdominal sonography is more comfortable for the patient but has more limitations than transvaginal sonography. Our aim was to determine whether transabdominal sonography could identify those women who should undergo transvaginal sonography for prediction of preterm birth.

METHODS

In this prospective study, women underwent cervical length measurements by transabdominal and transvaginal sonography between 20 and 29 gestational weeks and were followed until delivery. We assessed whether short cervical lengths on transabdominal sonography could predict short cervical lengths on transvaginal sonography and whether these measurements could predict preterm births (<34 gestational weeks).

RESULTS

The mean cervical lengths were not significantly different between the techniques (mean ± SD, 3.78 ± 0.82 and 3.82 ± 0.77 cm on transabdominal and transvaginal sonography, respectively; P = .09). The sensitivity of short cervical lengths (<2 cm) on transabdominal sonography for prediction of short cervical lengths on transvaginal sonography was 100%. The sensitivity, specificity, positive predictive value, negative predictive value, and relative risk of short cervical lengths (<2 cm) for predicting preterm birth were 21.4%, 98.68%, 50.00%, 95.32%, and 13.22 when using transabdominal sonography and 28.57%, 94.94%, 66.6%, 95.74%, and 17.78 when using transvaginal sonography, respectively. In an analysis that included cases with transabdominal sonography, the sensitivity of short cervical lengths for predicting preterm birth was increased.

CONCLUSIONS

Women whose cervical lengths are measurable and long on transabdominal sonography may not need transvaginal sonography. Women whose cervical lengths are unmeasurable or short (<2 or <2.5 cm) on transabdominal sonography should undergo transvaginal sonography to measure cervical lengths for prediction of preterm birth.

[Relation Between Stress During Pregnancy and Spontaneous Preterm Birth]

BACKGROUND

Preterm birth occurs before 37 completed weeks, its causes are multifactorial and vary according to the gestational age, ethnicity and geographical context. Although several medical/social factors have been clearly identified, over 50% of cases are unknown or unclear; however, psychopathological components emerge as potentially important risk factors.

OBJECTIVE

To determine the relationship between the presence of stress during pregnancy and spontaneous preterm birth.

MATERIAL AND METHODS

Through a study of cases and controls in a level III hospital, with a sample of 360 patients during the period from March to November of 2013, where sociodemographic characteristics were collected. In addition, they were applied scales social adjustment, coping strategies and social support. Logistic regression models were developed; psychological, biological and social. Based on the significant variables in each of these generated a final one.

RESULTS

The final model was found that stress during pregnancy increases the odds of spontaneous preterm birth 1.91 times (adjusted OR=2.91; 95%CI, 1.67-5.08; P<.05). Other significant variables were: history of preterm delivery, unplanned pregnancy, no emotional support, rural residence, inadequate prenatal care and non-stable partner.

CONCLUSIONS

The findings support the hypothesis that stress during pregnancy is associated with spontaneous preterm delivery.

Stem Cells: Potential Therapy for Neonatal Injury?

Stem cell transplantation (SCT) is an established first-line or adjunctive therapy for a variety of neonatal and adult diseases. New evidence in preclinical models as well as a few human studies show the potential utility of SCT in neuroprotection and in the modulation of inflammatory injury in at risk-neonates. This review briefly summarizes current understanding of human stem cell biology during ontogeny and present recent evidence supporting SCT as a viable approach for postinsult neonatal injury.

Group prenatal care: review of outcomes and recommendations for model implementation

The intent and delivery of prenatal care have evolved since its formal inception in the early 1900s. Group prenatal care offers an alternative care delivery model to the currently dominant prenatal care model. The group model has been associated with a number of improved perinatal outcomes including decreased preterm birth, higher birth weight, improved breast-feeding initiation and duration, decreased cesarean delivery, and greater patient satisfaction. This article outlines the tenets of CenteringPregnancy, the current dominant form of group prenatal care, reviews literature regarding perinatal outcomes related to group prenatal care, suggests future research agendas, and highlights relevant considerations when implementing this alternate model of prenatal health care delivery.

Activation of AMPK in human fetal membranes alleviates infection-induced expression of pro-inflammatory and pro-labour mediators

INTRODUCTION

In non-gestational tissues, the activation of adenosine monophosphate (AMP)-activated kinase (AMPK) is associated with potent anti-inflammatory actions. Infection and/or inflammation, by stimulating pro-inflammatory cytokines and matrix metalloproteinase (MMP)-9, play a central role in the rupture of fetal membranes. However, no studies have examined the role of AMPK in human labour.

METHODS

Fetal membranes, from term and preterm, were obtained from non-labouring and labouring women, and after preterm pre-labour rupture of membranes (PPROM). AMPK activity was assessed by Western blotting of phosphorylated AMPK expression. To determine the effect of AMPK activators on pro-inflammatory cytokines, fetal membranes were pre-treated with AMPK activators then stimulated with bacterial products LPS and flagellin or viral dsDNA analogue poly(I:C). Primary amnion cells were used to determine the effect of AMPK activators on IL-1β-stimulated MMP-9 expression.

RESULTS

AMPK activity was decreased with term labour. There was no effect of preterm labour. AMPK activity was also decreased in preterm fetal membranes, in the absence of labour, with PROM compared to intact membranes. AMPK activators AICAR, phenformin and A769662 significantly decreased IL-6 and IL-8 stimulated by LPS, flagellin and poly(I:C). Primary amnion cells treated with AMPK activators significantly decreased IL-1β-induced MMP-9 expression.

DISCUSSION

The decrease in AMPK activity in fetal membranes after spontaneous term labour and PPROM indicates an anti-inflammatory role for AMPK in human labour and delivery. The use of AMPK activators as possible therapeutics for threatened preterm labour would be an exciting future avenue of research.

Omega-3 Fatty acids and gestational length in a high-risk psychiatric population due to psychiatric morbidity and medication exposure during pregnancy

OBJECTIVE

Premature birth is associated with infant morbidity and mortality. Women with psychiatric disorders represent an at-risk population for premature delivery and other obstetrical complications. The primary aim of this study was to assess the association between omega-3 fatty acid use and length of gestation.

METHODS

Data from the National Pregnancy Registry for Atypical Antipsychotics were used. This prospective study included pregnant women exposed and unexposed to atypical antipsychotics during pregnancy. The outcomes of gestational length, birth weight, and preeclampsia were examined in relation to omega-3 use during pregnancy. Omega-3 use was operationalized from a first-trimester interview as a dichotomous variable.

RESULTS

Of 361 women who were examined for eligibility, 233 women had a singleton birth as well as a valid response on the omega-3 item and information on at least one of the outcome measures. Ninety-seven (41.6%) women used omega-3 during pregnancy. Omega-3 users were older, more educated, and more likely to be married than nonusers. The users were less likely to have smoked during their first trimester and were marginally less likely to use antidepressant medications anytime during pregnancy. There were no significant differences in primary diagnoses or atypical antipsychotic, alcohol, or prenatal vitamin use. In an unadjusted model, there was a significant increase of between 4 and 5 days (0.65 weeks; 0.00-1.25) in gestational length among the omega-3 users. This result was no longer significant after adjusting for confounding variables, with an increase of approximately 4 days (0.53 weeks; -0.11 to 1.16). Omega-3 use was not significantly associated with a difference in birth weight or preeclampsia.

CONCLUSIONS

We found a trend for a modestly increased length of gestation among the omega-3 fatty acid users, although these were not significant after controlling for the exposures of smoking and antidepressant use. We did not find a decreased risk for preeclampsia among the users of omega-3 fatty acids or increased birth weight. In consideration of the risk factors for obstetrical and neonatal complications as well as implications for infant and child development, it would be clinically important to understand the variables that may additively decrease obstetrical risks in this population.

The BRAzil MAGnesium (BRAMAG) trial: a randomized clinical trial of oral magnesium supplementation in pregnancy for the prevention of preterm birth and perinatal and maternal morbidity

BACKGROUND

Preterm birth is the leading cause of infant mortality globally, including Brazil. We will evaluate whether oral magnesium citrate reduces the risk of placental dysfunction and its negative consequences for both the fetus and mother, which, in turn, should reduce the need for indicated preterm delivery.

METHODS/DESIGN

We will complete a multicenter, randomized double-blind clinical trial comparing oral magnesium citrate 150 mg twice daily (n = 2000 women) to matched placebo (n = 1000 women), starting at 121/7 to 206/7 weeks gestation and continued until delivery. We will include women at higher risk for placental dysfunction, based on clinical factors from a prior pregnancy (e.g., prior preterm delivery, stillbirth or preeclampsia) or the current pregnancy (e.g., chronic hypertension, pre-pregnancy diabetes mellitus, maternal age > 35 years or pre-pregnancy maternal body mass index > 30 kg/m2). The primary perinatal outcome is a composite of preterm birth < 37 weeks gestation, stillbirth > 20 weeks gestation, neonatal death < 28 days, or SGA birthweight < 3rd percentile. The primary composite maternal outcome is preeclampsia arising < 37 weeks gestation, severe non-proteinuric hypertension arising < 37 weeks gestation, placental abruption, maternal stroke during pregnancy or ≤ 7 days after delivery, or maternal death during pregnancy or ≤ 7 days after delivery.

DISCUSSION

The results of this randomized clinical trial may be especially relevant in low and middle income countries that have high rates of prematurity and limited resources for acute newborn and maternal care.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02032186, registered December 19, 2013.

Low-complexity intrauterine pressure estimation using the Teager energy operator on electrohysterographic recordings

Monitoring the progression of maternal uterine activity provides important prognostic information during pregnancy and parturition. Currently used methods for intrauterine pressure (IUP) measurement are unsuitable for long-term observation of uterine activity. The abdominally measured electrohysterogram (EHG) provides a non-invasive alternative to the existing methods for long-term ambulatory uterine contraction monitoring. A new low-complexity method for IUP estimation based on the Teager energy (TE) operator is proposed. The TE operator was used as it mimics the physiologic phenomena underlying the generation of the EHG signals. Several EHG signal analysis methods for IUP estimation from the literature are compared with the new TE method. The comparison is based on correlation and root mean square error of the IUP estimate with the gold standard internally measured IUP as well as their respective computational complexity. The proposed method results in a superior IUP estimation accuracy and complexity compared to state-of-the-art methods from the literature, with a complexity as much as 55 times lower. Therefore, the proposed method offers a valuable new option for long-term ambulatory uterine monitoring.

Comparison of cervical lengths using transabdominal and transvaginal sonography in midpregnancy

OBJECTIVES

Cervical length assessment is helpful to predict and prevent preterm birth. However, transvaginal sonography is not easy to perform. The aim of this study was to investigate the relationship and discrepancies between cervical lengths measured by transabdominal and transvaginal sonography in midpregnancy.

METHODS

Transabdominal and transvaginal cervical lengths were measured in 255 pregnant women between 20 and 29 gestational weeks. The discrepancies in cervical lengths between the two methods were analyzed for the following maternal and fetal conditions: (1) vertex versus breech fetal presentation, (2) whether the fetal presenting part overlay the cervical internal os, (3) whether both the internal os and external os were visible or only the internal os was clearly visible, (4) maternal bladder filling status, (5) maternal age, (6) parity, and (7) gestational age.

RESULTS

The mean cervical lengths were not significantly different (mean ± SD, 3.88 ± 0.73 cm on transabdominal sonography and 3.93 ± 0.72 cm on transvaginal sonography; P = .129; Pearson r = 0.75). The 5th-percentile transabdominal cervical length was 26.0 mm, and the transvaginal length was 27.8 mm. There were significant discrepancies between the two methods in the cases in which a fetal presenting part overlay the internal os, in the cases in which the external os was not clearly visible, and in primiparous women. Transabdominal cervical measurements were consistently shorter than transvaginal measurements in the cases with discrepancies.

CONCLUSIONS

Transabdominal cervical length measurements are correlated with transvaginal measurements overall, and the transabdominal length is consistently shorter than the transvaginal length in cases with discrepancies. Transabdominal sonography could be used as a cervical length screening tool.

Could genetic polymorphisms related to oxidative stress modulate effects of heavy metals for risk of human preterm birth?

Human preterm birth (PTB) is a complex medical outcome influenced by a combination of genetic and environmental factors. Research on the causative factors of PTB has mostly focused on demographic, socio-behavioral and environmental risk factors. Recent studies turn the spotlight on the effects of heavy metals exposure on adverse pregnancy outcomes. Here we present and evaluate the hypothesis that heavy metals may cause PTB through oxidative stress, and that this effect may be modified by polymorphisms in genes related to oxidative stress. Indeed, accumulating data suggest that the risk of PTB is correlated with polymorphisms in genes involved in detoxification, oxidative stress and lipid metabolism. These and other polymorphisms have independently been associated with susceptibility to the adverse effects of heavy metals.

The prevention, diagnosis and treatment of premature labor

BACKGROUND

The percentage of preterm births in Germany is high at 9%, but stable. 77% of cases of perinatal death are in prematurely born infants. Intensive research efforts are being directed toward the development of new means of primary and secondary prevention, diagnostic assessment, and pharmacotherapy of premature labor.

METHODS

We review pertinent publications that were retrieved by a selective search of the literature from 1966 to 2012, including current meta-analyses from the Cochrane database and the guidelines of German and foreign obstetric societies.

RESULTS

Preterm labor is a multifactorial problem. The current treatment options are symptomatic, rather than causally directed. Preventive treatment with progesterone can lower the rate of preterm birth in high-risk groups by more than 30%. Transporting the pregnant women to an appropriately qualified perinatal care center and induction of fetal lung maturation lowers perinatal mortality. A variety of tocolytic drugs with different mechanisms of action (betamimetics, oxytocin antagonists, calcium-channel blockers, NO donors, and inhibitors of prostaglandin synthesis) can be used for individualized tocolytic treatment. Premature rupture of the membranes is an indication for antibiotics.

CONCLUSION

The goal of all attempts to prevent and treat preterm labor is to improve preterm infants' chances of surviving with as few complications as possible. The methods discussed here can be used to prolong pregnancies at risk for preterm labor and so to reduce perinatal morbidity and mortality.

The consequences of chorioamnionitis: preterm birth and effects on development

Preterm birth is a major cause of perinatal mortality and long-term morbidity. Chorioamnionitis is a common cause of preterm birth. Clinical chorioamnionitis, characterised by maternal fever, leukocytosis, tachycardia, uterine tenderness, and preterm rupture of membranes, is less common than subclinical/histologic chorioamnionitis, which is asymptomatic and defined by inflammation of the chorion, amnion, and placenta. Chorioamnionitis is often associated with a fetal inflammatory response. The fetal inflammatory response syndrome (FIRS) is defined by increased systemic inflammatory cytokine concentrations, funisitis, and fetal vasculitis. Clinical and epidemiological studies have demonstrated that FIRS leads to poor cardiorespiratory, neurological, and renal outcomes. These observations are further supported by experimental studies that have improved our understanding of the mechanisms responsible for these outcomes. This paper outlines clinical and experimental studies that have improved our current understanding of the mechanisms responsible for chorioamnionitis-induced preterm birth and explores the cellular and physiological mechanisms underlying poor cardiorespiratory, neural, retinal, and renal outcomes observed in preterm infants exposed to chorioamnionitis.

The underestimation of immaturity in late preterm infants

PURPOSE

Late preterm infants with gestational ages between 34 0/7 and 36 6/7 weeks are known to be at higher risk of mortality and morbidity than term newborns. This study aims to investigate the nature and frequency of neonatological complications in the late preterm population resulting in neonatal intensive care unit admissions as well as to draw obstetrical conclusions from the results.

METHODS

Neonatological outcomes of 893 consecutively born late preterm infants were evaluated and classified by the frequency of occurrence in relation to potential maternal or fetal risk factors.

RESULTS

Out of 893 late preterm infants, 528 (59.1 %) required intensive neonatal care. The incidence of apnea and bradycardia, the occurrence of feeding difficulties and the requirement of continuous positive airway pressure (CPAP) were inversely proportional to gestational age (p < 0.001). Gestational diabetes of the mother was more frequently associated with hypoglycemia (p < 0.001), but showed a reduced risk of hypothermia (p < 0.001). Small for gestational age neonates had a significantly lower rate of respiratory disorders (p < 0.001), but were more often affected by feeding difficulties (p < 0.01). Normal vaginal delivery had a significant advantage with regard to the necessity of CPAP (p < 0.01) and the occurrence of feeding difficulties (p < 0.05). Infants born by cesarean section were at higher risk of hypoglycemia (p < 0.001), but at lower risk of hyperbilirubinemia (p < 0.001).

CONCLUSIONS

The high risk of a problematic neonatological outcome in late preterms requires fundamental reconsideration. All efforts to prolong a pregnancy should be made beyond the 34th week of gestation.