Rethinking causal assumptions about maternal BMI, gestational weight gain, and adverse pregnancy outcomes.

BACKGROUND: The aim of this study was to evaluate commonly assumed causal relationships between body mass index (BMI), gestational weight gain (GWG), and adverse pregnancy outcomes, which have formed the basis of guidelines and interventions aimed at limiting GWG in women with overweight or obesity. We explored relationships between maternal BMI, total GWG (as a continuous variable and as 'excessive' GWG), and pregnancy outcomes (including infant birthweight measures and caesarean birth). METHODS: Analysis of individual participant data (IPD) from the i-WIP (International Weight Management in Pregnancy) Collaboration, from randomised trials of diet and/or physical activity interventions during pregnancy reporting GWG and maternal and neonatal outcomes. Women randomised to the control arm of 20 eligible randomised trials (4370 of 8908 participants) from the i-WIP dataset of 36 randomised trials (total 12,240 women). The main research questions were to characterise the relationship between maternal BMI and (a) total GWG, (b) the risk of 'excessive' GWG (using the Institute of Medicine's guidelines), and (c) adverse pregnancy outcomes as mediated via GWG versus other pathways to determine the extent to which the observed effect of maternal BMI on pregnancy outcomes is mediated via GWG. We utilised generalised linear models and regression-based mediation analyses within an IPD meta-analysis framework. RESULTS: Mean GWG decreased linearly as maternal BMI increased; however, the risk of 'excessive' GWG increased markedly at BMI category thresholds (i.e. between the normal and overweight BMI category threshold and between the overweight and obese BMI category threshold). Increasing maternal BMI was associated with increased risk of all pregnancy outcomes assessed; however, there was no evidence that this effect was mediated via effects on GWG. CONCLUSIONS: There is evidence of a meaningful relationship between maternal BMI and GWG and between maternal BMI and adverse pregnancy outcomes. There is no evidence that the effect of maternal BMI on outcomes is via an effect on GWG. Our analyses also cast doubt on the existence of a relationship between 'excessive' GWG and adverse pregnancy outcomes. Our findings challenge the practice of actively managing GWG throughout pregnancy.

Associations of gestational weight gain with the long-term postpartum weight gain, body mass index, waist circumference and abdominal obesity: A 27-year prospective cohort study.

BACKGROUND: This prospective cohort study aimed to investigate the associations between gestational weight gain (GWG) and long-term postpartum maternal weight gain, body mass index (BMI), waist circumference (WC), and the risk of general and abdominal obesity, beyond motherhood (some 27 y after childbirth). METHODS: Participants were 1953 women enrolled in the Mater-University of Queensland Study of Pregnancy cohort study that started in the early 1980 s, with the most recent follow-up at 27 y postpartum. We examined the prospective associations of GWG in pregnancy with weight, BMI, and WC and the risk of adiposity 27 y after the index pregnancy. We used linear and multinomial logistic regressions to examine the independent effect of GWG on each outcome, adjusting for potential confounders and mediators. RESULTS: The average GWG during pregnancy was 14.88 kg (SD 5.24). One in four women (25.50%) gained below the Institute of Medicine (IOM) recommendations and one in three (34.00%) gained excess weight during pregnancy. Every 100 g/week increment of GWG was associated with 2.0 (95% CI: 1.5, 2.6) kg, 0.7 (0.5, 0.9) kg/m2, 1.3 (0.8, 1.8) cm greater body weight, BMI, and WC, respectively 27 y postpartum. Women who gained inadequate weight in pregnancy had significantly lower odds of general obesity (OR; 0.70, 95% CI:0.53,0.94) or abdominal obesity (0.73; 0.56,0.96), whereas those who gained excess gestational weight had much higher odds of general obesity (4.49; 3.36,6.00) and abdominal obesity (3.09; 2.29,4.16). These associations were independent of potential confounders. CONCLUSION: Maternal GWG in pregnancy independently and strongly predicted beyond motherhood weight gain trajectory. GWG within IOM recommendation may prevent long-term development of both general and central obesity.

Healthful Eating Behaviors among Couples Contribute to Lower Gestational Weight Gain.

Through longitudinal analysis from the GLOWING cohort study, we examined the independent and joint relationships between couples' eating behaviors and gestational weight gain (GWG). Pregnant persons (n = 218) and their non-pregnant partners (n = 157) completed an Eating Inventory. GWG was calculated as gestation weight at 36 weeks minus that at 10 weeks. General linear models were used to examine the relationships between GWG and the pregnant persons, non-pregnant partners, and couples (n = 137; mean of pregnant persons and non-pregnant partners) cognitive restraint (range 0-21), dietary disinhibition (range 0-18), and perceived hunger (range 0-14), with higher scores reflecting poorer eating behaviors. The adjusted models included race/ethnicity, education, income, marital status, and age. The pregnant persons and their non-pregnant partners' cognitive restraint, dietary disinhibition, and perceived hunger scores were 9.8 ± 4.7, 4.8 ± 3.2, and 4.4 ± 2.5 and 6.6 ± 4.6, 5.4 ± 3.4, and 4.7 ± 3.2, respectively. Higher cognitive restraint scores among the pregnant persons and couples were positively associated with GWG (p ≤ 0.04 for both). Stratified analyses revealed this was significant for the pregnant persons with overweight (p ≤ 0.04). The non-pregnant partners' eating behaviors alone were not significantly associated with GWG (p ≥ 0.31 for all). The other explored relationships between GWG and the couples' eating behaviors were insignificant (p ≥ 0.12 for all). Among the pregnant persons and couples, reduced GWG may be achieved with higher levels of restrained eating. Involving non-pregnant partners in programs to optimize GWG may be beneficial.

Association of DPP-4 Concentrations with the Occurrence of Gestational Diabetes Mellitus and Excessive Gestational Weight Gain.

Gestational diabetes mellitus (GDM) is considered one of the most common diseases that occur during pregnancy. In addition to increasing the risk of numerous complications throughout gestation, it is also believed to have a long-term potential to impact the risk of developing type 2 diabetes mellitus (T2DM) and cardiovascular disease for the mother and her offspring. While there are clear guidelines for healthy weight gain in pregnancy depending on pre-pregnancy BMI, as well as dietary and training recommendations to achieve this, an increasing number of women are experiencing excessive gestational weight gain (EGWG). Such patients have a higher risk of developing GDM and gestational hypertension, as well as requiring caesarian delivery. Dipeptidyl peptidase-4 (DPP-4) is a glycoprotein that seems to play an important role in glucose metabolism, and inhibition of its activity positively affects glucose regulation. The aim of our study was to compare DPP-4 concentrations in patients with GDM and EGWG with healthy women. DPP-4 levels were assessed in serum and urine samples collected on the day of delivery. The bioelectrical impedance analysis (BIA) method was also used to analyze the body composition of patients on the second day of the postpartum period. DPP-4 serum concentrations were significantly higher in patients in the GDM and EGWG groups compared to healthy women. Urinary DPP-4 concentrations were significantly higher in the control and GDM groups than in the EGWG group. Serum DPP-4 levels were positively correlated with BMI measured before pregnancy, on the delivery day, and in the early postpartum period, among other factors. According to our knowledge, this is the first study to determine DPP-4 levels in EGWG patients. DPP-4 may be related to the occurrence of GDM and EGWG; however, this requires further research.

Effects of Weight Gain During Pregnancy in Normal-Weight Women on Changes in the Gut Microbiota of Pregnant Women in the Third Trimester.

With the improvement of living standards and the lack of nutrition awareness during pregnancy, the phenomenon of excessive weight gain (EWG) of pregnancy is increasing. EWG during pregnancy has profound effects on the health of mother and offspring. The role of intestinal flora in regulating metabolic diseases has gradually attracted attention in recent years. The study explored the effect of EWG during pregnancy on gut microbiota, and analyzed the diversity and composition of gut microbiota in pregnant women in third trimester. Fecal samples were collected and divided into: insufficient weight gain (IWG) during pregnancy (group A1, N = 4), and appropriate weight gain (AWG) during pregnancy (group A2, N = 9), and EWG during pregnancy (N = 9 in A3 group). MiSeq high-throughput sequencing technology and bioinformatics analysis were introduced to investigate relationship of gestational weight gain and maternal gut microbiota. General data analysis showed that gestational weight gain and delivery mode have significant differences among the three groups. The overall level and diversity of intestinal microbiota in A1 and A3 group were increased. Composition of gut microbiota has no difference among three groups at the phylum level, but species of gut microbiota were different. Alpha diversity index analysis showed that the richness of A3 group was increased versus A2 group. EWG during pregnancy affects the abundance and proportion of gut microbiota in the third trimester. Therefore, maintaining moderate weight gain during pregnancy helps to maintain intestinal homeostasis.

Low prenatal resting energy expenditure and high energy intake predict high gestational weight gain in pregnant women with overweight/obesity.

INTRODUCTION: Recent evidence suggests that low resting energy expenditure (REE) is associated with gestational weight gain (GWG). However, little research has examined whether REE explains GWG beyond the contributions of energy intake (EI) and physical activity (PA). This study examined the extent to which EI, PA, and REE were associated with and explained second trimester GWG in pregnant women with overweight/obesity. METHODS: Pregnant women with overweight/obesity (N = 26) participating in the Healthy Mom Zone study, a theoretically-based behavioral intervention that adapted the intervention dosage over time to regulate GWG completed weekly point estimates of EI (back-calculation), PA (wrist-worn activity monitor), and REE (mobile metabolism device) from 14- to 28-weeks gestation. Second trimester GWG was calculated as the weekly point estimate of weight from a Wi-Fi weight scale at gestational week 28 minus the weekly point estimate of weight at gestational week 14. RESULTS: Partial correlations revealed second trimester EI and PA were not significantly associated with second trimester GWG, but low second trimester REE was significantly associated with high second trimester GWG. Hierarchical regression analyses showed the model of fat-free mass, EI, PA, and REE explained 56% of the variance in second trimester GWG. Low REE was the strongest determinant followed by high EI; fat-free mass and PA were not significant predictors. CONCLUSIONS: While EI and PA remain important determinants of GWG, future researchers should explore the role of REE to inform individualized EI and PA goals to better regulate GWG.

Underreporting of Energy Intake Increases over Pregnancy: An Intensive Longitudinal Study of Women with Overweight and Obesity.

(1) Background: Energy intake (EI) underreporting is a widespread problem of great relevance to public health, yet is poorly described among pregnant women. This study aimed to describe and predict error in self-reported EI across pregnancy among women with overweight or obesity. (2) Methods: Participants were from the Healthy Mom Zone study, an adaptive intervention to regulate gestational weight gain (GWG) tested in a feasibility RCT and followed women (n = 21) with body mass index (BMI) ≥25 from 8−12 weeks to ~36 weeks gestation. Mobile health technology was used to measure daily weight (Wi-Fi Smart Scale), physical activity (activity monitor), and self-reported EI (MyFitnessPal App). Estimated EI was back-calculated daily from measured weight and physical activity data. Associations between underreporting and gestational age, demographics, pre-pregnancy BMI, GWG, perceived stress, and eating behaviors were tested. (3) Results: On average, women were 30.7 years old and primiparous (62%); reporting error was −38% ± 26 (range: −134% (underreporting) to 97% (overreporting)), representing an ~1134 kcal daily underestimation of EI (1404 observations). Estimated (back-calculated), but not self-reported, EI increased across gestation (p < 0.0001). Higher pre-pregnancy BMI (p = 0.01) and weekly GWG (p = 0.0007) was associated with greater underreporting. Underreporting was lower when participants reported higher stress (p = 0.02) and emotional eating (p < 0.0001) compared with their own average. (4) Conclusions: These findings suggest systemic underreporting in pregnant women with elevated BMI using a popular mobile app to monitor diet. Advances in technology that allow estimation of EI from weight and physical activity data may provide more accurate dietary self-monitoring during pregnancy.

Characterizing and Evaluating Diurnal Salivary Uric Acid Across Pregnancy Among Healthy Women.

Uric acid levels during pregnancy have been examined as a potential indicator of risk for gestational diabetes mellites, hypertension, and related adverse birth outcomes. However, evidence supporting the utility of serum uric acid levels in predicting poor maternal and fetal health has been mixed. The lack of consistent findings may be due to limitations inherent in serum-based biomeasure evaluations, such as minimal repeated assessments and variability in the timing of these assessments. To address these gaps, we examined repeated measurements of diurnal salivary uric acid (sUA) levels in a sample of 44 healthy women across early-mid and late pregnancy. We assessed potential covariates and confounds of sUA levels and diurnal trajectories, as well as associations between maternal weight gain and blood pressure during pregnancy and sUA concentrations. Using multilevel linear models, we found sUA increased across pregnancy and displayed a robust diurnal pattern with the highest concentrations at waking, a steep decline in the early morning, and decreasing levels across the day. Maternal pre-pregnancy BMI, age, prior-night sleep duration, and fetal sex were associated with sUA levels and/or diurnal slopes. Maternal blood pressure and gestational weight gain also showed significant associations with sUA levels across pregnancy. Our results expand upon those found with serum UA measurements. Further, they demonstrate the feasibility of using at-home, minimally-invasive saliva sampling procedures to track UA levels across pregnancy with potential applications for the long-term monitoring of maternal cardiometabolic risk.

Excessive gestational weight gain in early pregnancy and insufficient gestational weight gain in middle pregnancy increased risk of gestational diabetes mellitus.

BACKGROUND: Gestational weight gain (GWG) is associated with the risk of gestational diabetes mellitus (GDM). However, the effect of weight gain in different trimesters on the risk of GDM is unclear. This study aimed to evaluate the effect of GWG on GDM during different trimesters. METHODS: A birth cohort study was conducted from 2017 to 2020 in Shenzhen, China. In total, 51,205 participants were included comprising two models (early pregnancy model and middle pregnancy model). Gestational weight (kg) was measured at each prenatal clinical visit using a standardized weight scale. Logistic regression analysis was used to assess the risk of GDM. Interaction analysis and mediation effect analysis were performed in the middle pregnancy model. RESULTS: In the early pregnancy model, the risk of GDM was 0.858 times lower (95% confidence interval [CI]: 0.786, 0.937) with insufficient GWG (iGWG) and 1.201 times higher (95% CI: 1.097, 1.316) with excessive GWG after adjustment. In the middle pregnancy model, the risk of GDM associated with iGWG increased 1.595 times (95% CI: 1.418, 1.794) after adjustment; for excessive GWG, no significant difference was found ( P  = 0.223). Interaction analysis showed no interaction between GWG in early pregnancy (GWG-E) and GWG in middle pregnancy (GWG-M) ( F  = 1.268; P  = 0.280). The mediation effect analysis indicated that GWG-M plays a partial mediating role, with an effect proportion of 14.9%. CONCLUSIONS: eGWG-E and iGWG-M are associated with an increased risk of GDM. Strict control of weight gain in early pregnancy is needed, and sufficient nutrition should be provided in middle pregnancy.

Third trimester cortisol is positively associated with gestational weight gain in pregnant women with class one obesity.

BACKGROUND/OBJECTIVE: Prevalence of pre-pregnancy obesity and excessive gestational weight gain (GWG) are higher among women of color with low SES. Dysregulation of the Hypothalamic-Pituitary-Adrenal (HPA) axis and its end-product, cortisol, during pregnancy is hypothesized to be associated with excessive GWG. However, past studies have produced inconsistent findings and often did not include health disparities populations. This study examined the association between pre-pregnancy body mass index (BMI), third trimester diurnal cortisol, and GWG in low-income, predominantly Hispanic women. SUBJECTS/METHODS: The MADRES study is an ongoing prospective cohort study of primarily Hispanic, low-income pregnant women and their children in Los Angeles, California. Data from 176 participants were included in this study. Total cortisol secretion (area under the curve, AUC) was quantified using four salivary cortisol samples (awakening, 30 min after awakening, afternoon, and bedtime) that were collected at home on one day during the third trimester of pregnancy. Moderation of the association between total cortisol and GWG by pre-pregnancy BMI was tested using multiple linear regression with a multiplicative interaction term. RESULTS: There was no association between total cortisol secretion and GWG overall (p = 0.82), but the association between total cortisol and GWG was stronger for women with class 1 pre-pregnancy obesity compared to women with normal pre-pregnancy BMI (interaction term p = 0.04). CONCLUSIONS: Results suggest that obesity status before pregnancy may be exacerbating the physiological impact of cortisol on GWG.

Interpregnancy weight gain and childhood obesity: analysis of a UK population-based cohort.

BACKGROUND: Maternal obesity increases the risk of adverse long-term health outcomes in mother and child including childhood obesity. We aimed to investigate the association between interpregnancy weight gain between first and second pregnancies and risk of overweight and obesity in the second child. METHODS: We analysed the healthcare records of 4789 women in Hampshire, UK with their first two singleton live births within a population-based anonymised linked cohort of routine antenatal records (August 2004 and August 2014) with birth/early life data for their children. Measured maternal weight and reported height were recorded at the first antenatal appointment of each pregnancy. Measured child height and weight at 4-5 years were converted to age- and sex-adjusted body mass index (BMI z-score). Log-binomial regression was used to examine the association between maternal interpregnancy weight gain and risk of childhood overweight and obesity in the second child. This was analysed first in the whole sample and then stratified by baseline maternal BMI category. RESULTS: The prevalence of overweight/obesity in the second child was 19.1% in women who remained weight stable, compared with 28.3% in women with ≥3 kg/m2 weight gain. Interpregnancy gain of ≥3 kg/m2 was associated with increased risk of childhood overweight/obesity (adjusted relative risk (95% CI) 1.17 (1.02-1.34)), with attenuation on adjusting for birthweight of the second child (1.08 (0.94-1.24)). In women within the normal weight range at first pregnancy, the risks of childhood obesity (≥95th centile) were increased with gains of 1-3 kg/m2 (1.74 (1.07-2.83)) and ≥3 kg/m2 (1.87 (1.18-3.01)). CONCLUSION: Children of mothers within the normal weight range in their first pregnancy who started their second pregnancy with a considerably higher weight were more likely to have obesity at 4-5 years. Supporting return to pre-pregnancy weight and limiting weight gain between pregnancies may achieve better long-term maternal and offspring outcomes.

Does interpregnancy BMI change affect the risk of complications in the second pregnancy? Analysis of pooled data from Aberdeen, Finland and Malta.

OBJECTIVE: Weight management interventions during pregnancy have had limited success in reducing the risk of pregnancy complications. Focus has now shifted to pre-pregnancy counselling to optimise body weight before subsequent conception. We aimed to assess the effect of interpregnancy body mass index (BMI) change on the risk of perinatal complications in the second pregnancy. METHODS: A cohort study was performed using pooled maternity data from Aberdeen, Finland and Malta. Women with a BMI change of ±2 kg/m2 between their first and second pregnancies were compared with those who were BMI stable (remained within ±2 kg/m2). Outcomes assessed included pre-eclampsia (PE), intrauterine growth restriction (IUGR), preterm birth, birth weight, and stillbirth in the second pregnancy. We also assessed the effect of unit change in BMI for PE and IUGR. Logistic regression was used to calculate odds ratios with 95% confidence intervals. RESULTS: An increase of ≥2 kg/m2 between the first two pregnancies increased the risk of PE (1.66 (1.49-1.86)) and high birthweight (>4000 g) (1.06 (1.03-1.10)). A reduction of ≥2 kg/m2 increased the chance of IUGR (1.15 (1.01-1.31)) and preterm birth (1.14 (1.01-1.30)), while reducing the risk of instrumental delivery (0.75 (0.68-0.85)) and high birthweight (0.93 (0.87-0.98)). Reducing BMI did not significantly decrease PE risk in women with obesity or those with previous PE. A history of PE or IUGR in the first pregnancy was the strongest predictor of recurrence independent of interpregnancy BMI change (5.75 (5.30-6.24) and (7.44 (6.71-8.25), respectively). CONCLUSION: Changes in interpregnancy BMI have a modest impact on the risk of high birthweight, PE and IUGR in contrasting directions. However, a prior history of PE and IUGR is the dominant predictor of recurrence at second pregnancy.

Impact of pre-pregnancy body mass index and gestational weight gain on the risk of maternal and infant pregnancy complications in Korean women.

BACKGROUND/OBJECTIVE: Healthy weight maintenance before and during pregnancy has a significant effect on pregnancy outcomes; however, there are no specific guidelines for gestational weight gain in pregnant Korean women. Therefore, we investigated the impact of pre-pregnancy body mass index (BMI) and gestational weight gain on the risk of maternal and infant pregnancy complications in pregnant Korean women. METHODS: Study participants comprised 3454 singleton pregnant women from the Korean Pregnancy Outcome Study who had baseline examination and pregnancy outcome data. Maternal pre-pregnancy BMI and gestational weight gain were categorized according to the Asia-pacific regional guidelines and the Institute of Medicine recommendations, respectively. The primary outcome was any adverse outcomes, defined as the presence of one or more of the following: hypertensive disorders of pregnancy, gestational diabetes mellitus, peripartum depressive symptom, cesarean delivery, delivery complications, preterm birth, small or large weight infant, neonatal intensive care unit admission, or a congenital anomaly. Multiple logistic regression models were applied to examine the independent and combined impact of pre-pregnancy BMI and gestational weight gain on the risk of maternal and infant outcomes. RESULTS: Obesity before pregnancy significantly increased the risk of perinatal adverse outcomes by more than 2.5 times [odds ratio (OR): 2.512, 95% confidence interval (CI): 1.817-3.473]. Compared to that in women with appropriate gestational weight gain, women with excessive weight gain had a 36.4% incremental increase in the risk of any adverse outcomes [OR: 1.364, 95% CI: 1.115-1.670]. Moreover, women who were overweight or obese before pregnancy and had excessive gestational weight gain had a three-fold increase in the risk of adverse outcomes [OR: 3.460, 95% CI: 2.210-5.417]. CONCLUSION: This study highlights the need for appropriate weight recommendations before and during pregnancy to prevent perinatal complications in Korean women of childbearing age.

Higher Peripheral Cholesterol and a Positive Correlation With Risk for Large-For-Gestational-Age Neonates in Pre-Pregnancy Underweight Women.

Objective: As the high proportion of underweight pregnant women, omission of their weight gain and blood lipids management during gestation might lead to adverse pregnancy outcomes. This study aimed to determine the relationship between lipid profile and risks for adverse pregnancy outcomes in pre-pregnancy underweight women. Methods: This study was part of an ongoing cohort study including Chinese gravidas delivered from January 2015 to December 2016. Included subjects were grouped into underweight, normal-weight, and overweight by BMI before conception. Logistic regression was used to assess the association between lipid profiles during second trimester and adverse obstetric outcomes in each group. A subgroup analysis according to the gestational weight gain, in which subjects in each group were divided into above and within the Institute of Medicine (IOM) recommendations, was performed. Results: A total of 6, 223 women were included. The proportion of underweight (19.3%) was similar to that of overweight women (19.4%) in South China. Peripheral total cholesterol (TC) level in underweight women was significantly higher than that in overweight women (P <0.001). After adjusting maternal age, TC level was positively correlated to the risk for large-for-gestational-age (LGA) [aOR =2.24, 95%CI (1.08, 4.63)], and negatively related to the risk for small-for-gestational age (SGA) [aOR =0.71, 95%CI (0.59, 0.85)] in underweight women, but not in normal-weight or overweight women. The subgroup analysis showed that maternal TC level was positively correlated with the risk of LGA only in underweight women who gained weight more than the IOM recommendations. Conclusion: Underweight pregnant women with high TC levels had a higher risk for LGA, especially among women whose gestational weight gain were above the IOM recommendations. Therefore, clinical management of lipids and weight gain during gestation should also be recommended for underweight women.

Body Mass Index and Gestational Weight Gain Are Associated with Maternal and Neonatal Outcomes Based on Chinese Women.

The objective of the study is to analyze the association between early pregnancy body mass index (BMI), gestational weight gain (GWG), and maternal and neonatal outcomes. The retrospective cohort study was conducted at Quanzhou First Hospital Affiliated to Fujian Medical University from January 2018 to May 2021, with 552 women enrolled. Women were divided into the underweight group, normal weight group, overweight group, and obese group according to early pregnancy BMI. Univariate and multivariate logistic regression analyses were performed. The absolute risk of adverse maternal and neonatal outcomes in the early pregnancy BMI group was calculated to further analyze the association between GWG and adverse maternal and neonatal outcomes. Of the 552 women, 390 (70.65%) women had adverse maternal and neonatal outcomes. The result revealed that overweight was associated with increased risk of adverse maternal and neonatal outcomes (odds ratio (OR): 1.643, 95% confidence interval (CI): 1.006-2.684), maternal complications (OR: 1.937, 95% CI: 1.188-3.159), and large for gestational age (LGA) (OR: 1.905, 95% CI: 1.061-3.422). In the obese group, the risk of adverse maternal and neonatal outcomes (OR: 5.760, 95% CI: 1.997-16.786), maternal complications (OR: 3.112, 95% CI: 1.645-5.887), gestational diabetes mellitus (GDM) (OR: 2.943, 95% CI: 1.509-5.741), cesarean section (OR: 1.899, 95% CI: 1.002-3.599), and preterm delivery (OR: 4.752, 95% CI: 1.395-16.185) increased. Besides, there was an association between insufficient GWG and decreased risk of LGA (OR: 0.392, 95% CI: 0.187-0.826) and higher risk of preterm delivery (OR: 2.818, 95% CI: 1.171-6.784). This study demonstrates that BMI and GWG are related to maternal and neonatal outcomes. It is necessary to regularly monitor the weight of pregnant women during pregnancy. And regional guidelines for GWG also need to be explored.

Effects of Gestational Weight Gain on Delivery Outcomes in an Obese, Low-Income Population.

OBJECTIVE: To examine the effects of weight gain/loss on delivery outcomes stratified by class of obesity in an obese, low-income, predominantly minority population. METHODS: A retrospective review of a cohort of 1428 women receiving care at a large Medicaid clinic from 2013 to 2016 with pregravid body mass index ≥30 was conducted. Multinomial logistic regression analysis was used to compare differences in gestational weight change to the primary outcomes of birth-weight percentile and delivery type and secondary outcomes of preterm delivery, preterm labor, gestational diabetes mellitus, and gestational hypertension. RESULTS: Obesity class 1 patients who lost weight were more likely to have a small-for-gestational-age (SGA) infant compared with those who had recommended weight gain. Obesity classes 2 and 3 patients had no statistically significant increase in SGA infants with weight loss or weight gain below current recommendations. Obesity classes 1 and 2 patients with weight loss had a statistically significant increase in both preterm delivery and preterm labor; however, class 3 patients did not. Obesity class 3 patients who lost weight were significantly more likely to have gestational diabetes mellitus. CONCLUSIONS: Obesity class 3 women may benefit from less weight gain than current recommendations without increasing their risk of SGA infants or preterm birth, especially if gestational diabetes mellitus is present.

Associations between Maternal Diet, Body Composition and Gut Microbial Ecology in Pregnancy.

Maternal body composition, gestational weight gain (GWG) and diet quality influence offspring obesity risk. While the gut microbiome is thought to play a crucial role, it is understudied in pregnancy. Using a longitudinal pregnancy cohort, maternal anthropometrics, body composition, fecal microbiome and dietary intake were assessed at 12, 24 and 36 weeks of gestation. Fecal samples (n = 101, 98 and 107, at each trimester, respectively) were utilized for microbiome analysis via 16S rRNA amplicon sequencing. Data analysis included alpha- and beta-diversity measures and assessment of compositional changes using MaAsLin2. Correlation analyses of serum metabolic and anthropometric markers were performed against bacterial abundance and predicted functional pathways. α-diversity was unaltered by pregnancy stage or maternal obesity status. Actinobacteria, Lachnospiraceae, Akkermansia, Bifidobacterium, Streptococcus and Anaerotuncus abundances were associated with gestation stage. Maternal obesity status was associated with increased abundance of Lachnospiraceae, Bilophila, Dialister and Roseburia. Maternal BMI, fat mass, triglyceride and insulin levels were positively associated with Bilophila. Correlations of bacterial abundance with diet intake showed that Ruminococcus and Paraprevotella were associated with total fat and unsaturated fatty acid intake, while Collinsella and Anaerostipes were associated with protein intake. While causal relationships remain unclear, collectively, these findings indicate pregnancy- and maternal obesity-dependent interactions between dietary factors and the maternal gut microbiome.

Gestational body weight gain and risk of low birth weight or macrosomia in women of Japan: a nationwide cohort study.

OBJECTIVE: Both maternal prepregnancy body mass index (BMI) and gestational weight gain (GWG) influence maternal and pediatric outcomes. We sought to clarify the impact of prepregnancy BMI-specific GWG and its patterns on the risk of low birth weight (LBW) or macrosomia using data from a large nationwide study in Japan. METHODS: This cohort study (n = 98,052) used data from the Japan Environment and Children's Study (JECS). The outcome variables in this study were LBW and macrosomia. We stratified the subjects into groups according to prepregnancy BMI. RESULTS: GWG from pre-pregnancy to the first trimester had a small effect on the risk of LBW and macrosomia. From the first to second trimesters, insufficient GWG was associated with the risk of LBW, and from the second trimester to delivery, a GWG of less than 2 kg was associated with the risk of LBW. These associations were commonly observed in all prepregnancy BMI categories. Irrespective of the GWG from pre-pregnancy to the first trimester, GWG from the first to second trimesters affects LBW and/or macrosomia. Irrespective of the GWG from the first to second trimesters, GWG from the second trimester to delivery affects LBW and/or macrosomia. LBW or macrosomia was associated with the prevalence of a sustained low or high BMI percentile until three years of age, respectively. CONCLUSIONS: The present large national cohort study indicates that the risk of LBW or macrosomia is associated with GWG in women in Japan; the significance of this risk depends on the GWG patterns.