Prepregnancy body mass index and risk of preterm birth: association heterogeneity by preterm subgroups

Maternal pre-pregnancy body mass index and risk of preterm birth: a collaboration using large routine health datasets

BACKGROUND

Preterm birth (PTB) is a leading cause of child morbidity and mortality. Evidence suggests an increased risk with both maternal underweight and obesity, with some studies suggesting underweight might be a greater factor in spontaneous PTB (SPTB) and that the relationship might vary by parity. Previous studies have largely explored established body mass index (BMI) categories. Our aim was to compare associations of maternal pre-pregnancy BMI with any PTB, SPTB and medically indicated PTB (MPTB) among nulliparous and parous women across populations with differing characteristics, and to identify the optimal BMI with lowest risk for these outcomes.

METHODS

We used three UK datasets, two USA datasets and one each from South Australia, Norway and Denmark, together including just under 29 million pregnancies resulting in a live birth or stillbirth after 24 completed weeks gestation. Fractional polynomial multivariable logistic regression was used to examine the relationship of maternal BMI with any PTB, SPTB and MPTB, among nulliparous and parous women separately. The results were combined using a random effects meta-analysis. The estimated BMI at which risk was lowest was calculated via differentiation and a 95% confidence interval (CI) obtained using bootstrapping.

RESULTS

We found non-linear associations between BMI and all three outcomes, across all datasets. The adjusted risk of any PTB and MPTB was elevated at both low and high BMIs, whereas the risk of SPTB was increased at lower levels of BMI but remained low or increased only slightly with higher BMI. In the meta-analysed data, the lowest risk of any PTB was at a BMI of 22.5 kg/m2 (95% CI 21.5, 23.5) among nulliparous women and 25.9 kg/m2 (95% CI 24.1, 31.7) among multiparous women, with values of 20.4 kg/m2 (20.0, 21.1) and 22.2 kg/m2 (21.1, 24.3), respectively, for MPTB; for SPTB, the risk remained roughly largely constant above a BMI of around 25-30 kg/m2 regardless of parity.

CONCLUSIONS

Consistency of findings across different populations, despite differences between them in terms of the time period covered, the BMI distribution, missing data and control for key confounders, suggests that severe under- and overweight may play a role in PTB risk.

Intrapartum care and management of complications in women with obesity

Pregnant women with obesity are at considerable risk during their labor and delivery. The aim of obstetric care is the safe delivery of the baby and the maintenance of good health of the mother while providing an ongoing support for the family unit. The awareness and mitigation of risks associated with caring for women who are obese is vital in ensuring continued good outcomes. Transfer of women for labor care, presence of senior staff, bariatric resources, understanding of the progress of labor with an increase in body mass index, and preparation for complications are covered in this chapter.

Pre-pregnancy obesity is associated with greater systemic inflammation and increased risk of antenatal depression

BACKGROUND

Pre-pregnancy obesity is an emerging risk factor for perinatal depression. However, the underlying mechanisms remain unclear. We investigated the association between pre-pregnancy body mass index (BMI) and perinatal depressive symptoms in a large population-based pre-birth cohort, the Barwon Infant Study. We also assessed whether the levels of circulating inflammatory markers during pregnancy mediated this relationship.

METHODS

Depressive symptoms were assessed in 883 women using the Edinburgh Postnatal Depression Scale (EPDS) and psychological stress using the Perceived Stress Scale (PSS) at 28 weeks gestation and 4 weeks postpartum. Glycoprotein acetyls (GlycA), high-sensitivity C-reactive protein (hsCRP) and cytokines were assessed at 28 weeks gestation. We performed regression analyses, adjusted for potential confounders, and investigated mediation using nested counterfactual models.

RESULTS

The estimated effect of pre-pregnancy obesity (BMI ≥ 30 kg/m2) on antenatal EPDS scores was 1.05 points per kg/m2 increase in BMI (95% CI: 0.20, 1.90; p = 0.02). GlycA, hsCRP, interleukin (IL) -1ra and IL-6 were higher in women with obesity, compared to healthy weight women, while eotaxin and IL-4 were lower. Higher GlycA was associated with higher EPDS and PSS scores and partially mediated the association between pre-pregnancy obesity and EPDS/PSS scores in unadjusted models, but this association attenuated upon adjustment for socioeconomic adversity. IL-6 and eotaxin were negatively associated with EPDS/PSS scores, however there was no evidence for mediation.

CONCLUSIONS

Pre-pregnancy obesity increases the risk of antenatal depressive symptoms and is also associated with systemic inflammation during pregnancy. While discrete inflammatory markers are associated with antenatal depressive symptoms and perceived stress, their role in mediating the effects of pre-pregnancy obesity on antenatal depression requires further investigation.

Double burden of malnutrition and its associated factors among women in low and middle income countries: findings from 52 nationally representative data

BACKGROUND

Double burden of malnutrition (DBM) is an emerging global public health problem. The United Nations member states adopted eradicating all forms of malnutrition as an integral component of the global agenda. However, there is evidence of a high burden of undernutrition among women and rising rates of overweight and obesity, especially in low and middle income countries (LMICs). Therefore, this study aimed to investigate the prevalence and associated factors of underweight, overweight, and obesity among women of reproductive age in LMICs.

METHODS

Data for the study were drawn from a recent 52 Demographic and Health Surveys (DHS) conducted in LMICS. We included a sample of 1,099,187 women of reproductive age. A multilevel multinomial logistic regression model was used to identify factors associated with DBM. Adjusted relative risk ratio (RRR) with a 95% Confidence Interval (CI) was reported to show an association.

RESULTS

The prevalence of underweight, overweight, and obesity in LMICs among women of reproductive age was 15.2% (95% CI: 15.1-15.3), 19.0% (95% CI: 18.9- 19.1), and 9.1% (95% CI: 9.0-9.2), respectively. This study found that women aged 24-34 years, aged ≥ 35 years, with primary, secondary, and above educational level, from wealthy households, using modern contraceptives, exposed to media (radio and television), and with high parity (more than one birth) were more likely to have overweight and obesity and less likely to have underweight. Moreover, the risk of having obesity (RRR = 0.59; 95% CI = 0.58-0.60 and overweight (RRR = 0.78; 95% CI = 0.77-0.79) were lower among rural women, while the risk of being underweight was (RRR = 1.13; 95% CI = 1.11-1.15) higher among rural women compared to urban women.

CONCLUSION

The prevalence of underweight, overweight, and obesity was high among women of reproductive age in LMICs. Underweight, overweight, and obesity are influenced by sociodemographic, socioeconomic, and behavioral-related factors. This study shows that, in order to achieve Sustainable Development Goal 2, a multifaceted intervention approach should be considered to prevent both forms of malnutrition in women of reproductive age. This can be achieved by raising awareness and promoting healthy behaviors such as healthy eating and physical activity, especially among educated women, women from wealthy households, and women exposed to the media.

A Microphysiological Device to Model the Choriodecidual Interface Immune Status during Pregnancy

During human pregnancy the chorion (fetal) lines decidua (maternal) creating the feto-maternal interface. Despite their proximity, resident decidual immune cells remain quiescent during gestation and do not invade the chorion. Infection and infiltration of activated immune cells toward the chorion are often associated with preterm birth. However, the mechanisms that maintain choriodecidual immune homeostasis or compromise immune barrier functions remain unclear. To understand these processes, a two-chamber microphysiological system (MPS) was created to model the human choriodecidual immune interface under normal and infectious conditions in vitro. This MPS has outer (fetal chorion trophoblast cells) and inner chambers (maternal decidual + CD45+ cells [70:30 ratio]) connected by microchannels. Decidual cells were treated with LPS to mimic maternal infection, followed by immunostaining for HLA-DR and HLA-G, immune panel screening by imaging cytometry by time of flight, and immune regulatory factors IL-8 and IL-10, soluble HLA-G, and progesterone (ELISA). LPS induced a proinflammatory phenotype in the decidua characterized by a decrease in HLA-DR and an increase in IL-8 compared with controls. LPS treatment increased the influx of immune cells into the chorion, indicative of chorionitis. Cytometry by time of flight characterized immune cells in both chambers as active NK cells and neutrophils, with a decrease in the abundance of nonproinflammatory cytokine-producing NK cells and T cells. Conversely, chorion cells increased progesterone and soluble HLA-G production while maintaining HLA-G expression. These results highlight the utility of MPS to model choriodecidual immune cell infiltration and determine the complex maternal-fetal crosstalk to regulate immune balance during infection.

Latent class analysis of placental histopathology: a novel approach to classifying early and late preterm births

BACKGROUND

Neonatal morbidity attributable to prematurity predominantly occurs among early preterm births (<32 weeks) rather than late preterm births (32 to <37 weeks). Methods to distinguish early and late preterm births are lacking given the heterogeneity in pathophysiology and risk factors, including maternal obesity. Although preterm births are often characterized by clinical presentation (spontaneous or clinically indicated), classifying deliveries by placental features detected on histopathology reports may help identify subgroups of preterm births with similar etiology and risk factors. Latent class analysis is an empirical approach to characterize preterm births on the basis of observed combinations of placental features.

OBJECTIVE

To identify histopathologic markers that can distinguish early (<32 weeks) and late preterm births (32 to <37 weeks) that are also associated with maternal obesity and neonatal outcomes.

STUDY DESIGN

Women with a singleton preterm birth at University of Pittsburgh Medical Center Magee-Womens Hospital (Pittsburgh, PA) from 2008 to 2012 and a placental evaluation (89% of preterm births) were stratified into early (n=900, 61% spontaneous) and late preterm births (n=3362, 57% spontaneous). Prepregnancy body mass index was self-reported at first prenatal visit and 16 abstracted placental features were analyzed. Placental subgroups (ie, latent classes) of early and late preterm births were determined separately by latent class analysis of placental features. The optimal number of latent classes was selected by comparing fit statistics. The probability of latent class membership across prepregnancy body mass indexes was estimated in early preterm births and in late preterm births by an extension of multinomial regression called pseudo-class regression, adjusting for race, smoking, education, and parity. The frequencies of severe neonatal morbidity (composite outcome: respiratory distress, bronchopulmonary dysplasia, intraventricular hemorrhage, necrotizing enterocolitis, periventricular leukomalacia, patent ductus arteriosus, and retinopathy of prematurity), small-for-gestational-age, and length of neonatal intensive care unit stay were compared across latent classes by chi-square and Kruskal-Wallis tests.

RESULTS

Early preterm births were grouped into 4 latent classes based on placental histopathologic features: acute inflammation (38% of cases), maternal vascular malperfusion with inflammation (29%), maternal vascular malperfusion (25%), and fetal vascular thrombosis with hemorrhage (8%). As body mass index increased from 20 to 50kg/m2, the probability of maternal vascular malperfusion and fetal vascular thrombosis with hemorrhage increased, whereas the probability of maternal vascular malperfusion with inflammation decreased. There was minimal change in the probability of acute inflammation with increasing body mass index. Late preterm births also had 4 latent classes: maternal vascular malperfusion (22%), acute inflammation (12%), fetal vascular thrombosis with hemorrhage (9%), and low-risk pathology (58%). Body mass index was not associated with major changes in likelihood of the latent classes in late preterm births. Associations between body mass index and likelihood of the latent classes were not modified by type of delivery (spontaneous or indicated) in early or late preterm births. Maternal malperfusion and fetal vascular thrombosis with hemorrhage were associated with greater neonatal morbidity than the other latent classes in early and late preterm births.

CONCLUSION

Obesity may predispose women to early but not late preterm birth through placental vascular impairment. Latent class analysis of placental histopathologic data provides an evidence-based approach to group preterm births with shared underlying etiology and risk factors.

Prevalence and Risk Factors of Preterm Birth Among Pregnant Women Admitted at the Labor Ward of the Komfo Anokye Teaching Hospital, Ghana

Preterm birth is a global epidemic and a leading cause of neonatal mortality in Sub-Saharan Africa. We evaluated the prevalence and risk factors of preterm birth among women attending the labor ward for delivery at a tertiary hospital in Ghana. This comparative cross-sectional study was conducted among a cohort of 209 pregnant women admitted to the labor ward of the Komfo Anokye Teaching Hospital (KATH). Pregnant women who delivered between 28 and 36 completed weeks of gestation were classified as preterm delivery whereas those who delivered after 37–42 completed weeks were described as term. Sociodemographic, clinical, and obstetric data were collected from patient's folder and hospital archives. Categorical variables were analyzed and expressed as frequencies and proportions. We determined the association between obstetric factors and preterm delivery with multiple logistic regressions. Significance level of the strength of association was determined at p-value < 0.05. of the 209 participants, the prevalence of preterm birth was 37.3% (78/209) whereas 62.7% (131/209) delivered at Term. Intrauterine growth restriction (IUGR) [aOR = 2.15, 95% CI = (1.819.55), p = 0.0390], HELLP (hemolysis, elevated liver enzymes and low platelet count) syndrome [aOR = 3.94, 95% CI = (1.64–9.48), p = 0.0020], early gestational obesity [aOR = 2.11, 95% CI = (1.31–11.92), p = 0.0480] and preeclampsia [aOR = 4.56, 95% CI = (1.63–12.76), p = 0.004] were identified as independent risk factors of preterm birth. Prevalence of preterm birth was high among women attending labor admission at the Komfo Anokye Teaching Hospital and this was independently influenced by IUGR, HELLP syndrome, early gestational obesity, and preeclampsia. Identifying early signs of adverse pregnancy outcomes would inform the need for management policy to prevent high prevalence of preterm births.

Antenatal fetal surveillance of women with severe obesity

OBJECTIVE

To estimate the impact of body mass index (BMI) categories on duration of the nonstress test (NST), and the need for additional tests of fetal wellbeing or interventions.

METHODS

We conducted a retrospective cohort study of women with singleton pregnancies who had an NST for the indications of severe obesity (BMI ≥40 kg/m²), diabetes (pre-gestational or gestational), hypertensive disorders (chronic, gestational, and preeclampsia), and others between 1 January 2015 until 31 December 2016. NST durations (<30 and ≥30 min) were compared between groups first based on BMI (kg/m²) categories (<30, 30-39, 40-49, and ≥50) and then based on BMI and comorbidities: (1) severe obesity alone, (2) severe obesity and comorbidities, and (3) comorbidities alone. We compared the results of the NSTs, any subsequent fetal testing or interventions, and pregnancy outcomes among groups. Demographic information was compared using t-tests for continuous data and χ² analyses or Fisher's exact test, if the cells sizes were small, for categorical data. NST durations based on BMI groups, as well as BMI and comorbidities groups, were compared using linear mixed models and ANOVA.

RESULTS

Three hundred and fifty-one women underwent 1665 NSTs during the study period. After excluding women <18 and >50 years, gestational age <30 weeks, fetal anomalies, and NSTs lasting longer than 60 min, the study population included 313 women and 1471 NSTs. The mean NST duration in minutes of the BMI ≥50 (32.2 ± 9.6) category was significantly longer than the NST duration of the other BMI categories (BMI <30: 29.4 ± 8.3; BMI 30-39: 29.7 ± 8.9; BMI 40-49: 29.9 ± 8.3) (p=.05). Additionally, there was an increased percentage of NSTs lasting ≥30 min as the BMI category increased (p=.005). Women in the severe obesity and comorbidities group (n = 79) were less likely to have a reactive NST than women with severe obesity alone (n = 56) or comorbidities alone (n = 178) (92% vs. 97% vs. 98%, p<.0001). They were also more likely to need a biophysical profile (BPP) (8% vs. 3% vs. 2%, p<.0001). Of the 25 women that were sent to the labor and delivery unit for evaluation, 20 (80%) were admitted and delivered. The reasons for delivery were hypertension (n = 9, 45%), an abnormal NST (n = 5, 25%), oligohydramnios (n = 4, 20%), and labor (n = 2, 10%).

CONCLUSIONS

We found an increase in NST duration as the BMI increased. Women with severe obesity and a comorbidity were more likely to have a nonreactive NST and require a subsequent BPP. Of the 20 patients delivered due to NST surveillance, the most common indication for delivery was hypertension.

Artificial intelligence in obstetrics

This study reviews recent advances on the application of artificial intelligence for the early diagnosis of various maternal-fetal conditions such as preterm birth and abnormal fetal growth. It is found in this study that various machine learning methods have been successfully employed for different kinds of data capture with regard to early diagnosis of maternal-fetal conditions. With the more popular use of artificial intelligence, ethical issues should also be considered accordingly.

The effect of obesity in pregnancy and gestational weight gain on neonatal outcome in glucose-tolerant mothers

BACKGROUND

Most studies showing association between mothers with obesity in pregnancy or excessive gestational weight gain (GWG) and adverse neonatal outcome were cross-sectional or retrospective. Many included patients are with gestational diabetes mellitus (GDM), which is a strong risk factor for this adverse outcome. There are no prospective studies on this topic in Malaysia. This study aimed to examine prospectively the effects of obesity in pregnancy and GWG, independent of GDM, on neonatal outcome.

METHODS

Pregnant mothers in the first trimester, who presented to health clinics in Kuching, were screened. Mothers with existing diabetes mellitus or GDM were excluded using 75-g oral glucose tolerance test during the first and second trimesters. Participants with the first trimester BMI ≥ 23 kg/m2 were recruited as overweight/obese group, whereas those with BMI 18.5-22.9 kg/m2 were taken as the comparison group. At every trimester visit, mothers' weights were recorded. Babies' birth weight and occurrence of adverse neonatal outcome were documented.

RESULTS

There were 123 mothers recruited as overweight/obese group (mean BMI 29.0 kg/m2 ± 4.45) and 102 mothers as comparison group (mean BMI 20.4 kg/m2 ± 1.48). The number of low birth weight was similar between groups: 9.8% in overweight/obese group, 6.9% in the comparison group (p = 0.416). More than half of these babies were born to mothers with inadequate GWG (58.3% in obese group vs. 57.1% in control group, p = 0.077). There was no significant difference in the mean birth weight (3000 g ± 454.5 vs. 3038 g ± 340.8, p = 0.471), preterm delivery (8.13% vs. 3.92%, p = 0.193), and admission rate to neonatal intensive care unit (8.13% vs. 7.85%, p = 0.937) between groups. There was a positive correlation between the total GWG in overweight/obese group on baby's weight (r = 0.222, p = 0.013). Inadequate GWG was not correlated with lower birth weight (p = 0.052).

CONCLUSIONS

Obesity in pregnancy was not associated with poor neonatal outcome in this small sample of women in Malaysia. Total GWG showed a weak correlation with baby's birth weight in overweight/obese group.

Association of maternal pre-pregnancy low or increased body mass index with adverse pregnancy outcomes

This study investigated the association between pre-pregnancy body mass index (BMI) and adverse pregnancy outcomes among women participated in the National Free Preconception Health Examination Project in Guangdong Province, China, and explored these associations according to maternal age. Pre-pregnancy BMI was classified into underweight (BMI < 18.5 kg/m²), healthy weight (18.5–23.9 kg/m²), overweight (24.0–27.9 kg/m²), and obesity (≥ 28.0 kg/m²) according to Chinese criteria. Outcomes were preterm birth (PTB, delivery before 37 weeks of gestation), large for gestational age (LGA, birthweight above the 90th percentile for gestational age by infants’ sex), small for gestational age (SGA, birthweight below the 10th percentile for gestational age by infants’ sex), primary caesarean delivery, shoulder dystocia or birth injury, and stillbirth. Adjusted incidence risk ratios (aIRR) were calculated for underweight, overweight and obesity, respectively. Compared with healthy weight, underweight was associated with increased risk of PTB (aIRR 1.06, 95%CI 1.04–1.09) and SGA (1.23, 1.22–1.26) but inversely associated with LGA (0.83, 0.82–0.85), primary caesarean delivery (0.88, 0.87–0.90) and stillbirth (0.73, 0.53–0.99). Overweight was associated with increased risk of LGA (1.17, 1.14–1.19), primary caesarean delivery (1.18, 1.16–1.20) and stillbirth (1.44, 1.03–2.06), but inversely associated with SGA (0.92, 0.90–0.95) and shoulder dystocia or birth injury (0.86, 0.79–0.93). Obesity was associated with increased risk of PTB (1.12, 1.05–1.20), LGA (1.32, 1.27–1.37), primary caesarean delivery (1.45, 1.40–1.50), but inversely associated with SGA (0.92, 0.87–0.97). The aIRRs for underweight, overweight and obesity in relation to these adverse pregnancy outcomes ranged from 0.65 to 1.52 according to maternal age. In Chinese population, maternal pre-pregnancy BMI was significantly associated with the risk of adverse pregnancy outcomes and the risk differs according to maternal age. Further investigation is warranted to determine whether and how counselling and interventions for women with low or increased BMI before pregnancy can reduce the risk of adverse pregnancy outcomes.

Application of Artificial Intelligence in Early Diagnosis of Spontaneous Preterm Labor and Birth

This study reviews the current status and future prospective of knowledge on the use of artificial intelligence for the prediction of spontaneous preterm labor and birth (“preterm birth” hereafter). The summary of review suggests that different machine learning approaches would be optimal for different types of data regarding the prediction of preterm birth: the artificial neural network, logistic regression and/or the random forest for numeric data; the support vector machine for electrohysterogram data; the recurrent neural network for text data; and the convolutional neural network for image data. The ranges of performance measures were 0.79–0.94 for accuracy, 0.22–0.97 for sensitivity, 0.86–1.00 for specificity, and 0.54–0.83 for the area under the receiver operating characteristic curve. The following maternal variables were reported to be major determinants of preterm birth: delivery and pregestational body mass index, age, parity, predelivery systolic and diastolic blood pressure, twins, below high school graduation, infant sex, prior preterm birth, progesterone medication history, upper gastrointestinal tract symptom, gastroesophageal reflux disease, Helicobacter pylori, urban region, calcium channel blocker medication history, gestational diabetes mellitus, prior cone biopsy, cervical length, myomas and adenomyosis, insurance, marriage, religion, systemic lupus erythematosus, hydroxychloroquine sulfate, and increased cerebrospinal fluid and reduced cortical folding due to impaired brain growth.

Assessment of Hospital Rooming-in Practice in Abu Dhabi, United Arab Emirates: A Cross-Sectional Multi-Center Study

The World Health Organization (WHO) recommends rooming-in to reduce infant mortality rates. Little research has been done to assess practices such as rooming-in and its relation to breastfeeding in the United Arab Emirates (UAE). The aim of this study was to examine the prevalence of rooming-in during hospital stay among mothers with infants six months old and below, in addition to other associated factors in Abu Dhabi, UAE. This study utilized a sub-sample extracted from a dataset based on a convenience sample of mothers who were recruited from governmental maternal and child health centers as well as from the community. The purpose of the original research was to evaluate infant and young children's feeding practices. A pre-tested questionnaire was used during interviews with mothers once ethical clearance was in place. Multivariable logistic regression was conducted to describe the results. The original sample included 1822 participants, of which 804 infants met the inclusion criteria. The mean age for mothers and infants was 30.3 years and 3.5 months, respectively. The rate of rooming-in during hospital stay was 97.5%. Multivariable logistic regression analysis indicated factors associated with not rooming-in were low maternal age (Adjusted Odds Ratios (AOR) = 1.15, 95% confidence interval (CI): 1.03, 1.30), low gestational age (GA) (AOR = 1.90, 95% CI: 1.52, 2.36), abnormal pre-pregnancy body mass index (BMI) (AOR = 3.77, 95 % CI: 1.22, 11.76), and delayed initiation of breastfeeding (AOR = 4.47, 95 % CI: 1.08, 18.48). In the context of the high rate of rooming-in revealed in this study, there should be a focus on those groups who do not room-in (i.e., younger women and those with babies of a younger gestational age). Rooming-in practice provides self-confidence in taking care of a baby, knowledge about breastfeeding, and stimulates early-phase lactation.

Maternal Work and Spontaneous Preterm Birth: A Multicenter Observational Study in Brazil

Spontaneous preterm birth (sPTB) is a major pregnancy complication involving biological, social, behavioural and environmental mechanisms. Workload, shift and intensity may play a role in the occurrence of sPTB. This analysis is aimed addressing the effect of occupational activities on the risk for sPTB and the related outcomes. We conducted a secondary analysis of the EMIP study, a Brazilian multicentre cross-sectional study. For this analysis, we included 1,280 singleton sPTB and 1,136 singleton term birth cases. Independent variables included sociodemographic characteristics, clinical complications, work characteristics, and physical effort devoted to household chores. A backward multiple logistic regression analysis was applied for a model using work characteristics, controlled by cluster sampling design. On bivariate analysis, discontinuing work during pregnancy and working until the 7^th month of pregnancy were risks for premature birth while working during the 8^th - 9^th month of pregnancy, prolonged standing during work and doing household chores appeared to be protective against sPTB during pregnancy. Previous preterm birth, polyhydramnios, vaginal bleeding, stopping work during pregnancy, or working until the 7^th month of pregnancy were risk factors in the multivariate analysis. The protective effect of variables compatible with exertion during paid work may represent a reverse causality. Nevertheless, a reduced risk associated with household duties, and working until the 8^th-9^th month of pregnancy support the hypothesis that some sort of physical exertion may provide actual protection against sPTB.

Challenges for better care based on the course of maternal body mass index, weight gain and multiple outcome in twin pregnancies: a population-based retrospective cohort study in Hessen/Germany within 15 years

Introduction

Studies on maternal weight, gestational weight gain and associated outcomes in twin pregnancies are scarce. Therefore, we analyzed these items in a large cohort.

Methods

Data from 10,603/13,725 total twin pregnancies from the perinatal database in Hessen, Germany between 2000 and 2015 were used after exclusion of incomplete or non-plausible data sets. The course of maternal and perinatal outcomes was evaluated by linear and logistic regression models.

Results

The rate of twin pregnancies increased from 1.5 to 1.9% (p < 0.00001). Mean maternal age and pre-pregnancy weight rose from 31.4 to 32.9 years and from 68.2 to 71.2 kg, respectively (p < 0.001). The rates of women with a body mass index ≥ 30 kg/m² increased from 11.9 to 16.9% with a mean of 24.4–25.4 kg/m² (p < 0.001). The overall increase of maternal weight/week was 568 g, the 25th quartile was 419, the 75th quartile 692 g/week. The total and secondary caesareans increased from 68.6 to 73.3% and from 20.6 to 39.8%, respectively (p < 0.001). Rates of birthweight < 1500 g and of preterm birth < 28 and from 28 to 33 + 6 weeks all increased (p < 0.01). No significant changes were observed in the rates of stillbirth, perinatal mortality and NICU admissions.

Conclusion

The global trend of the obesity epidemic is equally observed in German twin pregnancies. The increase of mean maternal weight and the calculated quartiles specific for twin pregnancies help to identify inadequate weight gain in twin gestations. Policy makers should be aware of future health risks specified for singleton and twin gestations.

The comparison of plasma fibronectin in term and preterm delivery: A cross-sectional, descriptive-analytical study

Background

Preterm delivery is one of the main causes of infant death. Therefore, prediction of preterm delivery may eliminate a large number of prenatal complications.

Objective

The present study aimed to understand if preterm delivery can be predicted by assessing maternal plasma fibronectin concentration.

Materials and Methods

Serum samples from 105 pregnant women participating in this study were collected. The plasma fibronectin were measured at 24-28 wk of gestation and again at 32-36 wk of gestation. Unfortunately, only 65 of the 105 pregnant women, returned for the second sampling. The plasma fibronectin was analyzed using ELISA method and its concentration in term and preterm deliveries was compared. The delivery dates of all the women were also recorded.

Results

Out of 105 pregnant women, 28 delivered preterm (26.7%). The Plasma fibronectin concentrations in women with preterm delivery were higher than in those who delivered at term (p = 0.001). Accordingly, Plasma fibronectin concentrations were significantly higher in the second serum samples (p = 0.01). Plasma fibronectin concentrations was also higher in obese women and in those suffering from preeclampsia (p = 0.12) and gestational diabetes (p = 0.81).

Conclusion

Plasma fibronectin concentrations test could be used as an optional screening test for preterm delivery at 28 to 34 wk of gestation in pregnant women who prefer to avoid vaginal sampling.

The State of the Science of Preterm Birth: Assessing Contemporary Screening and Preventive Strategies

Preterm birth remains a leading cause of morbidity and mortality during the perinatal and neonatal periods. Now affecting approximately 1 in 10 births in the United States, preterm birth often occurs spontaneously and without a clear etiology. Careful assessment of risk factors, however, identifies vulnerable women allowing targeted interventions such as progestogen therapy and cerclage. This article is intended to highlight preterm birth risk factors and current predictive and preventive strategies for midwives, nurse practitioners, clinical nurse specialists, and perinatal nurses.

Role of Body Mass Index and gestational weight gain on preterm birth and adverse perinatal outcomes

The association of body mass index (BMI) and gestational weight gain (GWG) with preterm birth (PTB) remains controversial in the literature. To evaluate different maternal BMI and GWG categories, according to the initial BMI, in relation to different PTB subtypes and perinatal outcomes, we conducted a secondary analysis of a multicentre cross-sectional study, along with a nested case-control study including PTB from 20 centers in Brazil. Pre-pregnancy underweight was associated with a lower risk of provider-initiated PTB, while overweight and obesity were associated with a higher risk of provider-initiated PTB and a lower risk of spontaneous preterm birth. Insufficient gestational weight gain was associated with a higher prevalence of spontaneous PTB and preterm premature rupture of membranes. Excessive GWG correlated with a higher prevalence of provider-initiated PTB or preterm premature rupture of membranes. Irrespective of the initial BMI, the greater the rate of GWG, the higher the predicted probability of all PTB subtypes, except for spontaneous PTB in underweight women and those with normal BMI. On multivariate analysis, the initial BMI was shown to be the only factor associated with pi-PTB. Briefly, further studies evaluating the risk for PTB should consider that GWG may have a different role depending on the initial BMI and PTB subtype.

Screening for Preterm Birth: Potential for a Metabolomics Biomarker Panel

The aim of this preliminary study was to investigate the potential of maternal serum to provide metabolomic biomarker candidates for the prediction of spontaneous preterm birth (SPTB) in asymptomatic pregnant women at 15 and/or 20 weeks’ gestation. Metabolomics LC-MS datasets from serum samples at 15- and 20-weeks’ gestation from a cohort of approximately 50 cases (GA < 37 weeks) and 55 controls (GA > 41weeks) were analysed for candidate biomarkers predictive of SPTB. Lists of the top ranked candidate biomarkers from both multivariate and univariate analyses were produced. At the 20 weeks’ GA time-point these lists had high concordance with each other (85%). A subset of 4 of these features produce a biomarker panel that predicts SPTB with a partial Area Under the Curve (pAUC) of 12.2, a sensitivity of 87.8%, a specificity of 57.7% and a p-value of 0.0013 upon 10-fold cross validation using PanelomiX software. This biomarker panel contained mostly features from groups already associated in the literature with preterm birth and consisted of 4 features from the biological groups of “Bile Acids”, “Prostaglandins”, “Vitamin D and derivatives” and “Fatty Acids and Conjugates”.

Artificial Neural Network Analysis of Spontaneous Preterm Labor and Birth and Its Major Determinants

BACKGROUND

Little research based on the artificial neural network (ANN) is done on preterm birth (spontaneous preterm labor and birth) and its major determinants. This study uses an ANN for analyzing preterm birth and its major determinants.

METHODS

Data came from Anam Hospital in Seoul, Korea, with 596 obstetric patients during March 27, 2014 - August 21, 2018. Six machine learning methods were applied and compared for the prediction of preterm birth. Variable importance, the effect of a variable on model performance, was used for identifying major determinants of preterm birth. Analysis was done in December, 2018.

RESULTS

The accuracy of the ANN (0.9115) was similar with those of logistic regression and the random forest (0.9180 and 0.8918, respectively). Based on variable importance from the ANN, major determinants of preterm birth are body mass index (0.0164), hypertension (0.0131) and diabetes mellitus (0.0099) as well as prior cone biopsy (0.0099), prior placenta previa (0.0099), parity (0.0033), cervical length (0.0001), age (0.0001), prior preterm birth (0.0001) and myomas & adenomyosis (0.0001).

CONCLUSION

For preventing preterm birth, preventive measures for hypertension and diabetes mellitus are required alongside the promotion of cervical-length screening with different guidelines across the scope/type of prior conization.

McDonald versus Shirodkar cervical cerclage for the prevention of preterm birth: impact of body mass index

Objective: To compare obstetrical outcomes on women undergoing a McDonald or Shirodkar cerclage and to estimate the impact of maternal body mass index (BMI) on these outcomes. Methods: We conducted a retrospective review of the medical records of all women with singleton pregnancies who underwent placement of a McDonald or Shirodkar cerclage at St. Francis Hospital from January 2008 to October 2013. The subjects were categorized based on BMI groups (normal: less than 25 kg/m², overweight: 25-29 kg/m², obese: 30 kg/m² or more). The primary outcome was gestational age at delivery. Statistical analyses included chi-square, Student's t-test, and multivariable regression analysis. Results: Of 95 women, 47 (49.5%) received a Shirodkar, and 48 (50.5%) a McDonald cerclage. 16 women (16.8%) were categorized as normal weight, 35 (36.8%) as overweight, and 44 (46.3%) as obese. Gestational age at delivery differed significantly by group, decreasing with each categorical increase in BMI (normal: 39.0 ± 0.3 weeks; overweight: 36.6 ± 0.7 weeks; obese: 33.0 ± 1.1 weeks; p < .01). Overall, women receiving a Shirodkar cerclage had significantly longer pregnancies than women with a McDonald cerclage (36.7 ± 0.6 weeks versus 33.9 ± 1.0 weeks; p = .02). However, analysis showed a significant interaction between weight status and gestational age at delivery. Obese women had significantly longer pregnancies when they received a Shirodkar cerclage versus a McDonald cerclage (32.6 ± 1.0 weeks versus 28.8 ± 0.9 weeks; p < .01). However, there was no significant difference in gestational age at delivery between women categorized as normal/overweight (Shirodkar: 33.5 ± 0.9 weeks; McDonald: 32.9 ± 0.9 weeks; p = .63). Conclusions: Compared to obese women receiving a McDonald cerclage, obese women receiving a Shirodkar cerclage had significantly longer pregnancies. No significant differences in pregnancy duration were found in normal/overweight women regardless of cerclage technique. Pregnancy duration in obese women receiving a Shirodkar cerclage was similar to the pregnancy duration of normal/overweight women.

Relationship Between Common Mental Disorder Symptoms During Pregnancy and Preterm Birth Among Chinese Women in Wuhan

Objectives Few studies focus on the symptoms of common mental disorders during pregnancy (CMDP) and risk of preterm birth subtypes (PTB). The purpose of this study was to estimate the association between CMDP and PTB, and to examine whether or not the association between CMDP and PTB varies with the subtype of PTB in Chinese. Methods This population-based case control study, conducted in Wuhan, China, defined cases as every pregnant woman who had a PTB among all births in Wuhan, from June 10, 2011, to June 9, 2013. The same number of pregnant women who had term births was randomly selected as controls. The Electronic Perinatal Health Care Information System, a questionnaire designed for the study, provided data about the participants. Logistic regression analyses were used to model associations between CMDP and PTB, and to test associations between CMDP and two subtypes of PTB. Results The study recruited 8616 cases and an equal number of controls. We successfully collected maternal information on 6656 cases and controls for a response rate of 77.3 %. The incidence of PTB in Wuhan was 4.5 %. Spontaneous preterm births (SPTB) accounted for 60.1 %, and medically induced preterm births (IPTB) accounted for 39.9 % of preterm births. The prevalence rate of CMDP was 15.8 %. CMDP was slightly associated with PTB (crude OR 1.16, 95 % CI 1.01-1.32; adjusted OR 1.15, 95 % CI 1.00-1.32), further analyses showed CMDP was associated with IPTB (aOR 1.25, 95 % CI 1.04-1.50), but not with SPTB. Conclusion Our data suggest that CMDP is related to an increased risk of PTB, and that this association is primarily due to IPTB rather than SPTB.

Spontaneous and indicated preterm delivery risk is increased among overweight and obese women without prepregnancy chronic disease

OBJECTIVE

To investigate the independent impact of prepregnancy obesity on preterm delivery among women without chronic diseases by gestational age, preterm category and parity.

DESIGN

A retrospective cohort study.

SETTING

Data from the Consortium on Safe Labor (CSL) in the USA (2002-08).

POPULATION

Singleton deliveries at ≥23 weeks of gestation in the CSL (43 200 nulliparas and 63 129 multiparas) with a prepregnancy body mass index (BMI) ≥18.5 kg/m² and without chronic diseases.

METHODS

Association of prepregnancy BMI and the risk of preterm delivery was examined using Poisson regression with normal weight as reference.

MAIN OUTCOME MEASURES

Preterm deliveries were categorised by gestational age (extremely, very, moderate to late) and category (spontaneous, indicated, no recorded indication).

RESULTS

Relative risk of spontaneous preterm delivery was increased for extremely preterm among obese nulliparas (1.26, 95% CI: 0.94-1.70 for overweight; 1.88, 95% CI: 1.30-2.71 for obese class I; 1.99, 95% CI: 1.32-3.01 for obese class II/III) and decreased for moderate to late preterm delivery among overweight and obese multiparas (0.90, 95% CI: 0.83-0.97 for overweight; 0.87, 95% CI: 0.78-0.97 for obese class I; 0.79, 95% CI: 0.69-0.90 for obese class II/III). Indicated preterm delivery risk was increased with prepregnancy BMI in a dose-response manner for extremely preterm and moderate to late preterm among nulliparas, as it was for moderate to late preterm delivery among multiparas.

CONCLUSIONS

Prepregnancy BMI was associated with increased risk of preterm delivery even in the absence of chronic diseases, but the association was heterogeneous by preterm categories, gestational age and parity.

TWEETABLE ABSTRACT

Obese nulliparas without chronic disease had higher risk for spontaneous delivery <28 weeks of gestation.

Cause of neonatal deaths in Northern Ethiopia: a prospective cohort study

Background

Despite the significant reduction in childhood mortality, neonatal mortality has shown little or no concomitant decline worldwide. The dilemma arises in that the lack of documentation of cause of death in developing countries, where registration of vital events is virtually nonexistent. Understanding of the causes of death in neonates is important to guide public health interventions. The present study identifies the common causes of neonatal death in Ethiopia.

Methods

A prospective cohort study was conducted among neonates born between April 2014 and July 2014 in seven hospitals, in Tigray region, Ethiopia. Mothers were interviewed by midwifes respecting risk factors and infant survival. For neonates who died in hospital, causes of death were extracted from medical records, whereas a verbal autopsy method provided presumptive assignment of cause of death for those infants who died at home.

Results

Of the1152 live births, there were 68 deaths (63 per 1000 live births). Two thirds of deaths were attributable to prematurity 23 (34%) or asphyxia 21 (31%). Slight variance was seen between the morality patterns in early and late neonatal periods. In the early neonatal period, 37% were due to prematurity, while asphyxia (35%) was more common in the late neonatal period. All infection-related deaths occurred in neonate-mother dyads from rural areas.

Conclusion

Prematurity, asphyxia, and infections were the leading causes of neonatal deaths in Tigray region during the study period. Causes of deaths identified during early and late neonatal mortality differed, which clearly indicates the need for responsive and evidence-based interventions and policies.

Maternal Prepregnancy Body Mass Index and Small for Gestational Age Births in Chinese Women

BACKGROUND

Both high and low prepregnancy body mass index (BMI) has been associated with small for gestational age births (SGA; birthweight below the population specific 10th centile for the gestational age), but results remain inconsistent. We examined the association between maternal BMI and SGA, and evaluated if the associations were modified by preterm birth (being born prior to 37 weeks) status.

METHODS

A population-based cohort study was conducted in Wuhan, China from June 2011, to June 2013. Women who delivered a non-malformed livebirth (n = 76 695) were included using the Wuhan Maternal and Child Health Management Information System. Log-binomial regression models were used to analyse the associations between prepregnancy BMI, categorized using thresholds adapted to the Chinese population, and SGA. Stratified analyses were used to examine the relationship of prepregnancy BMI to preterm-SGA and term-SGA.

RESULTS

Of the 76 695 live births, 3058 (4.0%) were delivered preterm. For babies born at term, prepregnancy underweight (<18.5 kg/m² ) was associated with an increased risk of SGA, the adjusted risk ratio (RR) was 1.41 (95% confidence interval (CI) 1.33, 1.49), whereas, being overweight (24.0-27.9 kg/m² ) was associated with a decreased risk (RR 0.84, 95% CI 0.74, 0.94). For babies born preterm, prepregnancy underweight was not associated with risk of SGA, but being overweight was associated with an increased risk (RR 1.57, 95% CI 1.04, 2.35).

CONCLUSIONS

These data suggest that the association of overweight and underweight prepregnancy BMI and SGA differs depending on whether the baby is full term or preterm.

[Epidemiology and risk factors of preterm birth]

OBJECTIVE

To synthesize the available evidence regarding the incidence and several risk factors of preterm birth. To describe neonatal outcomes according to gestational age and to the context of delivery.

MATERIALS AND METHODS

Consultation of the Medline database.

RESULTS

In 2010, 11% of live births (15 million babies) occurred before 37 completed weeks of gestation worldwide. About 85% of these births were moderate to late preterm babies (32-36 weeks), 10% were very preterm babies (28-31 weeks) and 5% were extremely preterm babies (<28 weeks). In France, premature birth concerns 60,000 neonates every year, 12,000 of whom are born before 32 completed weeks of gestation. Half of them are delivered after spontaneous onset of labor or preterm premature rupture of the membranes, and the other half are provider-initiated preterm births. Several maternal factors are associated with preterm birth, including sociodemographic, obstetrical, psychological, and genetic factors; paternal and environmental factors are also involved. Gestational age is highly associated with neonatal mortality and with short- and long-term morbidities. Pregnancy complications and the context of delivery also have an impact on neonatal outcomes.

CONCLUSION

Preterm birth is one of the leading cause of the under-five mortality and of neurodevelopmental impairment worldwide; it remains a major public health issue.

Pre-term and post-term births: predictors and implications on neonatal mortality in Northern Ethiopia

BACKGROUND

Pre-term and post-term births are major determinants of neonatal mortality, including short- and long-term morbidity. In developing countries, where pre-term and post-term births are disproportionately common, the magnitude and underlying causes are not well understood, and evidence is required to design appropriate interventions. This study measured the incidence and identified risk factors of pre-term birth and post-term births in Ethiopia. In addition, it examined the effects of pre-term and post-term birth on neonatal mortality.

METHOD

This study is a portion of prospective cohort study conducted on 1152 live births born between April and July 2014 in seven hospitals in Tigray region, Northern Ethiopia. Neonatal mortality and birth outcomes were considered as dependent variables. Data were collected using a structured questionnaire and weekly neonatal follow up directed at midwives. Data were described using frequency, percentage, ratio of relative risk (RRR), and 95 % confidence interval (CI). We used multinomial and binary logistic regression to identify independent predictors of birth outcome and neonatal mortality respectively.

RESULT

The prevalence of pre-term and post term births was 8.1 % and 6.0 % respectively. Underweight maternal body mass index (RRR: 0.47, CI: 0.22-0.99), medium reported income (RRR: 0.26, CI: 0.12-0.5), length of neonate (RRR: 0.05, CI: 0.01-0.41), and multiple births (RRR: 2.86, CI: 1.4-5.650) were associated with pre-term birth. Predictors for post-term birth were overweight maternal body mass index (RRR: 3.88, CI: 1.01-15.05), high reported income mothers (RRR: 2.17, CI:1.1-4.3), as well as unmarried, widowed and divorced marital status (RRR:2.43, CI:1.02-5.80). With regards to binary logistic regression, pre-term birth (RR: 2.45, CI: 1.45-4.04) was an independent predictor for neonatal mortality, but this was not true for post-term births (RR: 0.45, CI: 0.07-2.96).

CONCLUSION

Socioeconomic and proximate factors are important predictors for pre-term and post-term births. Empowering women in terms of income status and controlling body mass index within the normal range are recommended. In addition, early detection and close antenatal follow-ups for mothers, who are at risk before and during pregnancy, are necessary to prevent both pre-term and post-term births.

Gestational weight gain and preterm birth in obese women: a systematic review and meta-analysis

BACKGROUND

Prepregnant obesity is a global concern and gestational weight gain has been found to influence the risks of preterm birth.

OBJECTIVE

To assess the relationship between gestational weight gain and risk for preterm birth in obese women.

SEARCH STRATEGY

Four electronic databases were searched from 18 February through to 28 April 2015.

SELECTION CRITERIA

Primary research reporting preterm birth as an outcome in obese women and gestational weight gain as a variable that could be compared to the 2009 Institute of Medicine's recommendations.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trials for inclusion. The Newcastle Ottawa Scale was used to assess study bias.

MAIN RESULTS

Our search identified six studies meeting the inclusion criteria; five were conducted in the USA and one in Peru. Four studies with a total of 10 171 obese women were meta-analysed. Significant heterogeneity was found between studies in the pooled analysis. Results for indicated preterm birth in obese women with gestational weight gain above the Institute of Medicine's recommendations showed increased risk (adjusted odds ratio 1.54; 95% CI 1.09-2.16).

CONCLUSIONS

Available science on this topic is limited to special populations of obese pregnant women. Generalisable research is needed to assess the variation in risk for preterm birth in obese women by differences in gestational weight gain and class of obesity controlling for significant variables in the pathway to preterm birth. This research has the potential to illuminate new science impacting preterm birth and interventions for prevention.

Synergistic effect of maternal obesity and periodontitis on preterm birth in women with pre-eclampsia: a prospective study

AIM

The aim of this study was to investigate if pregnant women with both obesity and periodontitis are more likely to experience preterm birth (PTB) in women with pre-eclampsia (PE) than pregnant women with only obesity or only periodontitis.

MATERIALS AND METHODS

The study examined a total of 328 pregnant women at 21-24 weeks of gestation. Overweight and obesity was defined based on criteria proposed by the WHO Expert Consultation. Periodontal conditions were assessed by measuring periodontal clinical attachment loss. PTB was defined as delivery at <37 weeks, and PE was defined as blood pressure higher than 140/90 mmHg on two separate occasions with at least 1+ proteinuria on a random urine screen after the 20th week of pregnancy.

RESULTS

After adjusting for other important cofactors, pregnant women with periodontitis were 5.56 times [95% confidence interval (CI) = 1.22-25.39] more likely to have PTB with PE than women without periodontitis. The association was much stronger (odds ratio = 15.94, 95% CI = 3.31-76.71) in women with both obesity and periodontitis.

CONCLUSIONS

Our results of this study indicate that pregnant women with both pre-pregnancy obesity and periodontitis are significantly more likely to have PTB with PE than pregnant women with only periodontitis.

The Burden of Provider-Initiated Preterm Birth and Associated Factors: Evidence from the Brazilian Multicenter Study on Preterm Birth (EMIP)

Background

About 15 million children are born under 37 weeks of gestation worldwide. Prematurity is the leading cause of neonatal deaths and short/long term morbidities, entailing consequences not only for the individual, but also their family, health agencies, facilities and all community. The provider-initiated preterm birth is currently one of the most important obstetric conditions related to preterm births, particularly in middle and high income countries, thus decreasing the need for therapeutic preterm birth is essential to reduce global prematurity. Therefore detailed knowledge on the factors associated with provider-initiated preterm birth is essential for the efforts to reduce preterm birth rates and its consequences. In this current analysis we aimed to assess the proportion of provider-initiated (pi-PTB) among preterm births in Brazil and identify associated factors.

Methods and Findings

This is an analysis of a multicenter cross-sectional study with a nested case-control component called Brazilian Multicenter Study on Preterm Birth (EMIP). EMIP was conducted in 20 referral obstetric hospitals located in the three most populated of the five Brazilian regions. We analysed data of women with pi-PTB, defined as childbirth occurring at less than 37 weeks, medically indicated for maternal/fetal compromise or both; and women with term birth, childbirth at or after 37 weeks. Maternal, sociodemographic, obstetric, prenatal care, delivery, and postnatal characteristics were assessed as possible factors associated with pi-PTB, compared to term births. The overall prevalence of preterm births was 12.3%. Of these, approximately one-third of cases were initiated by the provider. Hypertensive disorders, placental abruption, and diabetes were the main maternal conditions leading to pi-PTB. Caesarean section was the most common mode of delivery. Chronic hypertension (OR 7.47; 95%CI 4.02–13.88), preeclampsia/eclampsia/HELLP syndrome (OR 15.35; 6.57–35.88), multiple pregnancy (OR 12.49; 4.86–32.05), and chronic diabetes (OR 5.24; 2.68–10.25) were the most significant factors independently associated with pi-PTB.

Conclusions

pi-PTB is responsible for about one-third of all preterm births, requiring special attention. The decision-making process relative to the choice of provider-initiated birth is complex, and many factors should be elucidated to improve strategies for its prevention, including evidence-based guidelines on proper management of the corresponding clinical conditions.

Folic acid supplementation, preconception body mass index, and preterm delivery: findings from the preconception cohort data in a Chinese rural population

BACKGROUND

Folic acid (FA) supplementation before and during the first trimester can reduce the risk of occurrence of preterm delivery (PTD). Preconception body mass index (BMI) is also associated with PTD. This study aimed to investigate the combined effect of FA supplements and preconception BMI on the risk of PTD.

METHODS

The data of a cohort from 2010-2011 that was obtained through a preconception care service in China was used (including 172,206 women). A multivariable regression model was used to investigate the association between maternal preconception conditions and the risk of PTD. The interaction of preconception BMI and FA supplementation was measured by a logistic regression model.

RESULTS

Taking FA supplements in the preconception period or in the first trimester reduced the risk of PTD (odds ratio [OR] = 0.58 and OR = 0.61, respectively). Women with an abnormal BMI had an increased risk of PTD (OR = 1.09, OR = 1.10, and OR = 1.17 for underweight, overweight, and obese, respectively). Preconception BMI showed an interaction with the protective effect of FA supplementation for PTD. With regard to the interaction of FA supplementation, the adjusted odds ratio (aOR) was 0.57 (95% CI: 0.51, 0.64) in underweight women, 0.85 (95% CI: 0.73, 0.98) in overweight women, and 0.77 (95% CI, 0.65, 0.91) in obese women. Preconception BMI also showed an interaction with the time of FA supplementation. Women with a normal BMI who began to take FA supplements in the preconception period had the lowest risk of PTD (aORs: 0.58 vs. 0.65 beginning in the first trimester). The aORs at preconception and the first trimester in the underweight group were 0.56 vs. 0.60. The aORs at preconception and the first trimester were 0.94 vs. 0.65 and 1.15 vs. 0.60 in the overweight and obesity groups, respectively.

CONCLUSIONS

In our study, FA supplements reduced the risk of PTD, while abnormal BMI raised the risk of PTD, although higher BMI categories did not have this higher risk once adjusted analysis was conducted. The protective effect of FA supplementation for PTD was reduced in women with overweight or obesity. To get better protection of FA supplementation, women with normal BMI or underweight should begin to use in preconception, while women with overweight or obesity should begin to use after conception.

Induction of labour and intrapartum care in obese women

The rising incidence of obesity in pregnancy has a significant impact on the provision of health services around the world. Due to the pathophysiological processes associated with the condition, the obese pregnant woman is at increased risks of induction of labour, caesarean section, post-partum haemorrhage, infection, longer hospital stay, macrosomia and higher perinatal morbidity and mortality. Labour is more likely to be prolonged and dysfunctional, leading to the requirements for higher doses of oxytocin and increased risks of operative deliveries and morbidity. A multidisciplinary approach to the planning of antenatal, intrapartum and postnatal care is vital to ensure a safe outcome for the obese pregnant woman and her baby. The need for supervision and attendance by senior obstetric staff is increased, emphasising the need to identify the appropriate place of birth for this high-risk group of women, placing a significant strain on the resources of health-care providers.