Inter-pregnancy weight change impacts placental weight and is associated with the risk of adverse pregnancy outcomes in the second pregnancy

Quantifying the effect of interpregnancy maternal weight and smoking status changes on childhood overweight and obesity in a UK population-based cohort

BACKGROUND

Maternal preconception and pregnancy exposures have been linked to offspring adiposity. We aimed to quantify the effect of changes in maternal weight and smoking status between pregnancies on childhood overweight/obesity (≥ 85th centile) and obesity (≥ 95th centile) rates in second children.

METHODS

Records for 5612 women were drawn from a population-based cohort of routinely collected antenatal healthcare records (2003-2014) linked to measured child body mass index (BMI) age 4-5 years. We applied the parametric G-formula to estimate the effect of hypothetical changes between pregnancy-1 and pregnancy-2 compared to the natural course scenario (without change) on child-2 BMI.

RESULTS

Observed overweight/obesity and obesity in child-2 at age 4-5 years were 22.2% and 8·5%, respectively. We estimated that if all mothers started pregnancy-2 with BMI 18·5-24·9 kg/m² and all smokers stopped smoking, then child-2 overweight/obesity and obesity natural course estimates of 22.3% (95% CI 21.2-23.5) and 8·3% (7·6-9·1), would be reduced to 18.5% (17.4-19.9) and 6.2% (5.5-7.0), respectively. For mothers who started pregnancy-1 with BMI 18·5-24·9 kg/m², if all smokers stopped smoking, child-2 overweight/obesity and obesity natural course estimates of 17.3% (16.0-18.6) and 5·9% (5·0-6·7) would be reduced to 16.0% (14.6-17.3) and 4·9% (4·1-5·7), respectively. For mothers who started pregnancy-1 with BMI ≥30 kg/m², if BMI was 18·5-24·9 kg/m² prior to pregnancy-2, child-2 overweight/obesity and obesity natural course estimates of 38.6% (34.7-42.3) and 17·7% (15·1-20·9) would be reduced to 31.3% (23.8-40.0) and 12.5 (8.3-17.4), respectively. If BMI was 25.0-29.9 kg/m² prior to pregnancy-2, these estimates would be 34.5% (29.4-40.4) and 14.6% (11.2-17.8), respectively.

CONCLUSION

Interventions supporting women to lose/maintain weight and quit smoking between pregnancies could help reduce rates of overweight/obesity and obesity in second children. The most effective interventions may vary by maternal BMI prior to the first pregnancy.

Interpregnancy weight change and neonatal and infant outcomes: A systematic review and meta-analysis

PURPOSE

To synthesize evidence regarding the association between interpregnancy weight change (IPWC) in consecutive pregnancies and neonatal or infant outcomes in the subsequent pregnancy.

METHODS

Search strategy was implemented in MEDLINE, EMBASE, Web of Science, Scopus and Cochrane Library from their inception to 13 November 2023. The most adjusted odds ratio (OR) or risk ratio estimates provided by original studies were used to calculate pooled risk ratios and their corresponding 95 % confidence intervals (CI) with the DerSimonian and Laird random effects method. Publication bias was assessed by funnel plots and Egger's method, and risk of bias was assessed with The NewcastleOttawa Quality Assessment Scale.

RESULTS

Thirty-seven observational studies were included. Interpregnancy weight loss or gain were associated with large for gestational age (OR: 0.89; 95 % CI: 0.84-0.94; I2 = 83.6 % and OR: 1.33; 95 % CI:1.26-1.40; I2 = 98.9 %), and stillbirth risk (OR: 1.10; 95 % CI: 1.01-1.18; I2 = 0.0 % and OR: 1.21; 95 % CI: 1.09-1.33; I2 = 60.2 %,).

CONCLUSIONS

Findings highlight the importance of managing weight between interpregnancy periods, although these findings should be interpreted cautiously because of the possible influence of social determinants of health and other factors.

Prepregnancy weight loss and maternal metabolic and inflammatory biomarkers during pregnancy: An analysis of National Health and Nutrition Examination Survey

AIM

Women with overweight or obesity are recommended to lose weight before conception to optimize pregnancy outcomes. However, the obstetrical implications of prepregnancy weight loss have been minimally examined. The objective of this study was to investigate the association between prepregnancy weight loss and maternal metabolic and inflammatory profiles during a subsequent pregnancy.

METHODS

This study was a retrospective analysis of National Health and Nutrition Examination Survey data (2003-2018). Participants were women who were pregnant at the time of assessment. Prepregnancy weight loss was described as percent weight change based on self-reported baseline (1 year before pregnancy) and prepregnancy weight. Metabolic (e.g., blood pressure [BP]) and inflammatory biomarkers (i.e., high-sensitivity C-reactive protein [hs-CRP]) were determined by standard medical tests. Statistical analyses included linear regressions with appropriate imputation, weighting, and variance estimation techniques.

RESULTS

Participants (N = 236) reported a mean percent weight loss of 4.6% (standard error [SE] = 0.3%) during the year before pregnancy. Regression models showed that prepregnancy weight loss was inversely associated with levels of total cholesterol (β = -1.24, p = 0.01), low-density lipoprotein-cholesterol (β = -0.79, p < 0.01), and high-density lipoprotein-cholesterol (β = -0.18, p < 0.01). The effect of prepregnancy weight loss on BP, insulin sensitivity, and hs-CRP was not significant, although there was a trend toward higher levels of diastolic BP (β = 0.24, p = 0.07) and hs-CRP (β = 0.10, p = 0.08).

CONCLUSIONS

This study found favorable changes in lipid profiles following prepregnancy weight loss. Due to limitations such as a relatively small sample size, self-reported weight measures, and missing data on several outcome variables, future studies are needed to confirm study findings.

Inter-pregnancy interval and placental weight. A population based follow-up study in Norway

INTRODUCTION

We studied changes in placental weight from the first to the second delivery according to length of the inter-pregnancy interval.

METHODS

We followed all women in Norway from their first to their second successive singleton pregnancy during the years 1999-2019, a total of 271 184 women. We used data from the Medical Birth Registry of Norway and studied changes in placental weight (in grams (g)) according to the length of the inter-pregnancy. Adjustments were made for year and maternal age at first delivery, changes in the prevalence of maternal diseases (hypertension and diabetes), and a new father to the second pregnancy.

RESULTS

Mean placental weight increased from 655 g at the first delivery to 680 g at the second. The adjusted increase in placental weight was highest at inter-pregnancy intervals <6 months; 38.2 g (95 % CI 33.0g-43.4 g) versus 23.2 g (95 % CI 18.8g-27.7 g) at inter-pregnancy interval 6-17 months. At inter-pregnancy intervals ≥18 months, placental weight remained higher than at the first delivery, but was non-different from inter-pregnancy intervals 6-17 months. Also, after additional adjustment for daily smoking and body mass index in sub-samples, we found the highest increase in placental weight at the shortest inter-pregnancy interval. We estimated no difference in gestational age at delivery or placental to birthweight ratio according to inter-pregnancy interval.

DISCUSSION

Placental weight increased from the first to the second pregnancy, and the increase was most pronounced at short inter-pregnancy intervals. The biological causes and implications of such findings remain to be studied.

Interpregnancy Body Mass Index Change and Offspring Mortality Risk following the Second Pregnancy

OBJECTIVE

The aim of the study is to examine the impact of maternal interpregnancy body mass index (BMI) change on subsequent offspring mortality risk.

STUDY DESIGN

This is a retrospective cohort study of women who had two consecutive live singleton deliveries of at least 20 weeks' gestation from the Utah Population Database. Our exposure was defined as interpregnancy BMI change from the date of first delivery to the conception date of subsequent pregnancy. We categorized BMI change as: < - 1, -1 to 0, 0 to <1 (reference), 1 to 2, 2 to 4, ≥4 kg/m2. Our primary outcome was all-cause age-specific mortality during four time periods: neonatal (≤28 days), infant (29 days to <1 year old), childhood ((≥1 to <5 years old), and late childhood (5 to <18 years old). We also examined mortality specifically attributed to congenital anomalies. Analyses used Cox proportional hazard models stratified by full term (≥37 weeks) and preterm (<37 weeks) deliveries. All models were adjusted for relevant confounders.

RESULTS

Of 266,752 women, among full-term deliveries, women with a BMI increase of 4 kg/m2 or more had an increased risk of neonatal mortality in their subsequent pregnancy (hazard ratio or HR = 1.72, 95% confidence interval or CI: 1.23-2.41) Women who lost 1 kg/m2 or more between deliveries also had increased neonatal mortality (HR = 1.46, 95% CI: 1.04-2.05). There were no differences in infant, early, or late childhood mortality by interpregnancy BMI change. Maternal interpregnancy interval weight loss of 1 kg/m2 or more and weight gain of ≥4 kg/m2 also had increased risk of mortality associated with congenital anomalies or conditions arising during the neonatal period following their subsequent delivery.

CONCLUSION

Women with significant interpregnancy weight gain and modest weight loss have a significant increased risk of neonatal mortality following their subsequent pregnancy.

KEY POINTS

· Significant weight gain between deliveries increases the risk of neonatal death.. · Modest weight loss between deliveries increases the risk of neonatal death.. · This risk may be partially explained by increased risk of congenital malformations..

Developmental Programming in Animal Models: Critical Evidence of Current Environmental Negative Changes

The Developmental Origins of Health and Disease (DOHaD) approach answers questions surrounding the early events suffered by the mother during reproductive stages that can either partially or permanently influence the developmental programming of children, predisposing them to be either healthy or exhibit negative health outcomes in adulthood. Globally, vulnerable populations tend to present high obesity rates, including among school-age children and women of reproductive age. In addition, adults suffer from high rates of diabetes, hypertension, cardiovascular, and other metabolic diseases. The increase in metabolic outcomes has been associated with the combination of maternal womb conditions and adult lifestyle-related factors such as malnutrition and obesity, smoking habits, and alcoholism. However, to date, "new environmental changes" have recently been considered negative factors of development, such as maternal sedentary lifestyle, lack of maternal attachment during lactation, overcrowding, smog, overurbanization, industrialization, noise pollution, and psychosocial stress experienced during the current SARS-CoV-2 pandemic. Therefore, it is important to recognize how all these factors impact offspring development during pregnancy and lactation, a period in which the subject cannot protect itself from these mechanisms. This review aims to introduce the importance of studying DOHaD, discuss classical programming studies, and address the importance of studying new emerging programming mechanisms, known as actual lifestyle factors, during pregnancy and lactation.

Emerging Concepts in Innate Lymphoid Cells, Memory, and Reproduction

Members of the innate immune system, innate lymphoid cells (ILCs), encompass five major populations (Natural Killer (NK) cells, ILC1s, ILC2s, ILC3s, and lymphoid tissue inducer cells) whose functions include defense against pathogens, surveillance of tumorigenesis, and regulation of tissue homeostasis and remodeling. ILCs are present in the uterine environment of humans and mice and are dynamically regulated during the reproductive cycle and pregnancy. These cells have been repurposed to support pregnancy promoting maternal immune tolerance and placental development. To accomplish their tasks, immune cells employ several cellular and molecular mechanisms. They have the capacity to remember a previously encountered antigen and mount a more effective response to succeeding events. Memory responses are not an exclusive feature of the adaptive immune system, but also occur in innate immune cells. Innate immune memory has already been demonstrated in monocytes/macrophages, neutrophils, dendritic cells, and ILCs. A population of decidual NK cells characterized by elevated expression of NKG2C and LILRB1 as well as a distinctive transcriptional and epigenetic profile was found to expand during subsequent pregnancies in humans. These cells secrete high amounts of interferon-γ and vascular endothelial growth factor likely favoring placentation. Similarly, uterine ILC1s in mice upregulate CXCR6 and expand in second pregnancies. These data provide evidence on the development of immunological memory of pregnancy. In this article, the characteristics, functions, and localization of ILCs are reviewed, emphasizing available data on the uterine environment. Following, the concept of innate immune memory and its mechanisms, which include epigenetic changes and metabolic rewiring, are presented. Finally, the emerging role of innate immune memory on reproduction is discussed. Advances in the comprehension of ILC functions and innate immune memory may contribute to uncovering the immunological mechanisms underlying female fertility/infertility, placental development, and distinct outcomes in second pregnancies related to higher birth weight and lower incidence of complications.

Preconceptional maternal weight loss and hypertensive disorders in pregnancy: a systematic review and meta-analysis

BACKGROUND

Hypertensive disorders of pregnancy (HDP), including pregnancy-induced hypertension (PIH), Preeclampsia (PE), Hemolysis Elevated Liver enzymes and Low Platelets (HELLP) and chronic hypertension, are leading causes of maternal and perinatal morbidity and mortality. Although the pathophysiology of HDP is complex, preconceptional weight reduction in obese women might reduce these complications. We conducted a systematic review and meta-analysis to investigate the effectiveness of preconceptional weight loss by lifestyle intervention or bariatric surgery in overweight and obese women and the reduction of the risk of HDP.

METHODS AND RESULTS

Databases are searched until September 2019 resulting in 2547 articles: 110 full-text analysis and 29 detailed analysis. Reduced risks were shown for HDP in seven articles (n = 4381) of weight loss after lifestyle intervention or bariatric surgery (OR range 0.10-0.64), for PIH in four articles (n = 46,976) (OR range 0.14-0.79), and for PE in seven articles (n = 169,734) (OR range 0.14-0.84). The stratified analysis of weight loss after lifestyle intervention and bariatric surgery shows comparable results. The meta-analysis of 20 studies of the effectiveness of lifestyle intervention and bariatric surgery revealed reduced risks of HDP (OR 0.45 (95% CI 0.32-0.63)), PIH (OR 0.61 (95%CI 0.44-0.85)) and PE (OR 0.67 (95%CI 0.51-0.88)).

CONCLUSIONS

Preconceptional weight loss after lifestyle intervention or bariatric surgery is effective in reducing risks of HDP, PIH and PE, and emphasizes the need to optimize weight in overweight and obese women with a child wish. More research is recommended to investigate short-term and long-term beneficial and harmful side-effects of these interventions on maternal and offspring health.

Pregnancy Outcomes after Preeclampsia: The Effects of Interpregnancy Weight Change

OBJECTIVE

This study aimed to examine the effects of interpregnancy weight change on pregnancy outcomes, including recurrent preeclampsia, preterm birth, small-for-gestational age (SGA), large-for-gestational age (LGA), and cesarean delivery, among women with a history of preeclampsia. We also evaluated whether these associations were modified by prepregnancy body mass index (BMI) category in the first pregnancy (BMI < 25 vs. ≥25 kg/m²) and if associations were present among women who maintained a healthy BMI category in both pregnancies.

STUDY DESIGN

We conducted a population-based retrospective cohort study including 15,108 women who delivered their first two nonanomalous singleton live births in Missouri (1989-2005) and experienced preeclampsia in the first pregnancy. We performed Poisson regression with robust error variance to estimate relative risks and 95% confidence intervals for outcomes of interest after controlling for potential confounders.

RESULTS

Interpregnancy weight gain was associated with increased risk of recurrent preeclampsia, LGA, and cesarean delivery. These risks increased in a "dose-response" manner with increasing magnitude of interpregnancy weight gain and were generally more pronounced among women who were underweight or normal weight in the first pregnancy. Interpregnancy weight loss exceeding 1 BMI unit was associated with increased risk of SGA among underweight and normal weight women, while interpregnancy weight loss exceeding 2 BMI units was associated with reduced risk of recurrent preeclampsia among overweight and obese women.

CONCLUSION

Even small changes in interpregnancy weight may significantly affect pregnancy outcomes among formerly preeclamptic women. Appropriate weight management between pregnancies has the potential to attenuate such risks.

KEY POINTS

· Interpregnancy weight change among formerly preeclamptic women significantly affects pregnancy outcomes.. · Interpregnancy weight gain is associated with increased risk of recurrent preeclampsia, large-for-gestational-age and cesarean delivery.. · Interpregnancy weight loss is associated with increased risk of small-for-gestational age and recurrent preeclampsia..

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.

Interpregnancy weight change and recurrence of gestational diabetes mellitus: a population-based cohort study

OBJECTIVE

To estimate recurrence risk of gestational diabetes mellitus (GDM) by interpregnancy weight change.

DESIGN

Population-based cohort study.

SETTING AND POPULATION

Data from the Swedish (1992-2010) and the Norwegian (2006-2014) Medical Birth Registries on 2763 women with GDM in first pregnancy, registered with their first two singleton births and available information on height and weight.

METHODS

Interpregnancy weight change (BMI in second pregnancy minus BMI in first pregnancy) was categorised in six groups by BMI units. Relative risks (RRs) of GDM recurrence were obtained by general linear models for the binary family and adjusted for confounders. Analyses were stratified by BMI in first pregnancy (<25 and ≥25 kg/m² ).

MAIN OUTCOME MEASURE

GDM in second pregnancy.

RESULTS

Among overweight/obese women (BMI ≥25), recurrence risk of GDM decreased in women who reduced their BMI by 1-2 units (relative risk [RR] 0.80, 95% CI 0.65-0.99) and >2 units (RR 0.72, 95% CI 0.59-0.89) and increased if BMI increased by ≥4 units (RR 1.26, 95% CI 1.05-1.51) compared wth women with stable BMI (-1 to 1 units). In normal weight women (BMI <25), risk of GDM recurrence increased if BMI increased by 2-4 units (RR 1.32, 95% CI 1.08-1.60) and ≥4 units (RR 1.61, 95% CI 1.28-2.02) compared with women with stable BMI.

CONCLUSION

Interpregnancy weight loss reduced risk of GDM recurrence in overweight/obese women. Weight gain between pregnancies increased recurrence risk for GDM in both normal and overweight/obese women. Our findings highlight the importance of weight management in the interconception window in women with a history of GDM.

TWEETABLE ABSTRACT

Interpregnancy weight loss reduces recurrence of gestational diabetes mellitus in overweight/obese women.

Maternal weight change between successive pregnancies: an opportunity for lifecourse obesity prevention

Maternal obesity is a major risk factor for adverse health outcomes for both the mother and the child, including the serious public health problem of childhood obesity which is globally on the rise. Given the relatively intensive contact with health/care professionals following birth, the interpregnancy period provides a golden opportunity to focus on preconception and family health, and to introduce interventions that support mothers to achieve or maintain a healthy weight in preparation for their next pregnancy. In this review, we summarise the evidence on the association between interpregnancy weight gain with birth and obesity outcomes in the offspring. Gaining weight between pregnancies is associated with an increased risk of large-for-gestational age (LGA) birth, a predictor of childhood obesity, and weight loss between pregnancies in women with overweight or obesity seems protective against recurrent LGA. Interpregnancy weight loss seems to be negatively associated with birthweight. There is some suggestion that interpregnancy weight change may be associated with preterm birth, but the mechanisms are unclear and the direction depends if it is spontaneous or indicated. There is limited evidence on the direct positive link between maternal interpregnancy weight gain with gestational diabetes, pre-eclampsia, gestational hypertension and obesity or overweight in childhood, with no studies using adult offspring adiposity outcomes. Improving preconception health and optimising weight before pregnancy could contribute to tackling the rise in childhood obesity. Research testing the feasibility, acceptability and effectiveness of interventions to optimise maternal weight and health during this period is needed, particularly in high-risk and disadvantaged groups.

Association between maternal lifestyle factors and low birth weight in preterm and term births: a case-control study

Background

It has been reported that lifestyle factors may affect birth weight; however, few studies have explored the association between lifestyle factors and low birth weight in preterm and term births in China. The objective of this study was to explore the effect of lifestyle on low birth weight in preterm and term births.

Methods

This case-control study was conducted in fourteen hospitals in Jiangmen, Guangdong Province. Data were collected from August 2015 to May 2016 using a standard questionnaire. Data were analysed using logistic regression.

Results

Women who delivered preterm and were physically active (1–3 times per week and ≥ 4 times per week) had reduced odds of having low birth weight babies (aOR = 0.584, 95%CI = 0.394–0.867 and, aOR = 0.516, 95%CI = 0.355–0.752, respectively). Pregnant women who had insufficient gestational weight gain had increased odds of having low birth weight babies (aOR = 2.272, 95%CI = 1.626–3.176). Women exposed to passive smoking had an increased risk of delivering low birth weight infants (aOR = 1.404, 95%CI = 1.057–1.864). Insufficient gestational weight gain and excessive gestational weight gain were both significantly associated with low birth weight (aOR = 1.484, 95%CI = 1.103–1.998 and aOR = 0.369, 95%CI = 0.236–0.577, respectively) for term deliveries. In addition, parity, history of low birth weight, antenatal care and gestational hypertension were significantly associated with the likelihood of low birth weight.

Conclusion

Pregnant women without exercise contraindications should remain physically active. Pregnant women should be aware of the negative effects of smoke and be aware of strategies to protect themselves from passive smoke exposure. Hospitals should inform pregnant women of the importance appropriate gestational weight gain. These recommendations should be put into practice to decrease the prevalence of low birth weight infants.

The impact of periconceptional maternal lifestyle on clinical features and biomarkers of placental development and function: a systematic review

BACKGROUND

Worldwide, placenta-related complications contribute to adverse pregnancy outcomes, such as pre-eclampsia, fetal growth restriction and preterm birth, with implications for the future health of mothers and offspring. The placenta develops in the periconception period and forms the interface between mother and embryo/fetus. An unhealthy periconceptional maternal lifestyle, such as smoking, alcohol and under- and over-nutrition, can detrimentally influence placental development and function.

OBJECTIVE AND RATIONALE

The impact of maternal lifestyle on placental health is largely unknown. Therefore, we aim to summarize the evidence of the impact of periconceptional maternal lifestyle on clinical features and biomarkers of placental development and function throughout pregnancy.

SEARCH METHODS

A comprehensive search in Medline, Embase, Pubmed, The Cochrane Library Web of Science and Google Scholar was conducted. The search strategy included keywords related to the maternal lifestyle, smoking, alcohol, caffeine, nutrition (including folic acid supplement intake) and body weight. For placental markers throughout pregnancy, keywords related to ultrasound imaging, serum biomarkers and histological characteristics were used. We included randomized controlled trials and observational studies published between January 2000 and March 2017 and restricted the analysis to singleton pregnancies and maternal periconceptional lifestyle. Methodological quality was scored using the ErasmusAGE tool. A protocol of this systematic review has been registered in PROSPERO International prospective register of systematic reviews (PROSPERO 2016:CRD42016045596).

OUTCOMES

Of 2593 unique citations found, 82 studies were included. The median quality score was 5 (range: 0-10). The findings revealed that maternal smoking was associated with lower first-trimester placental vascularization flow indices, higher second- and third-trimester resistance of the uterine and umbilical arteries and lower resistance of the middle cerebral artery. Although a negative impact of smoking on placental weight was expected, this was less clear. Alcohol use was associated with a lower placental weight. One study described higher second- and third-trimester placental growth factor (PlGF) levels after periconceptional alcohol use. None of the studies looked at caffeine intake. Adequate nutrition in the first trimester, periconceptional folic acid supplement intake and strong adherence to a Mediterranean diet, were all associated with a lower resistance of the uterine and umbilical arteries in the second and third trimester. A low caloric intake resulted in a lower placental weight, length, breadth, thickness, area and volume. Higher maternal body weight was associated with a larger placenta measured by ultrasound in the second and third trimester of pregnancy or weighed at birth. In addition, higher maternal body weight was associated with decreased PlGF-levels.

WIDER IMPLICATIONS

Evidence of the impact of periconceptional maternal lifestyle on placental health was demonstrated. However, due to poorly defined lifestyle exposures and time windows of investigation, unstandardized measurements of placenta-related outcomes and small sample sizes of the included studies, a cautious interpretation of the effect estimates is indicated. We suggest that future research should focus more on physiological consequences of unhealthy lifestyle during the critical periconception window. Moreover, we foresee that new evidence will support the development of lifestyle interventions to improve the health of mothers and their offspring from the earliest moment in life.

The impact of interpregnancy weight change on perinatal outcomes in women and their children: A systematic review and meta-analysis

Prepregnancy overweight and obesity are associated with higher risk of perinatal complications. However, the effect of weight change prior to pregnancy on perinatal outcome is largely unknown. Therefore, it is aimed to examine the impact on perinatal outcomes of interpregnancy BMI change in women of different BMI categories. The MEDLINE, EMBASE, LILACS, and CINAHL databases were searched (1990-August 2019). Observational studies on interpregnancy BMI change were selected. Outcomes evaluated were gestational diabetes mellitus (GDM), preeclampsia, gestational hypertension (GH), cesarean section, preterm birth, and newborns being large (LGA) or small (SGA) for gestational age. Meta-analyses and meta-regression analyses were executed. Thirty studies were included (n > 1 million). Interpregnancy BMI gain was associated with a higher risk of GDM (for BMI gain ≥3 kg/m² : OR 2.21; [95%CI 1.53-3.19]), preeclampsia (1.77 [1.53-2.04]), GH (1.78 [1.61-1.97]), cesarean section (1.32 [1.24-1.39]), and LGA (1.54 [1.28-1.86]). The effects of BMI gain were most pronounced in women with BMI <25 kg/m² before the first pregnancy regarding GDM, GH, and cesarean section. Except for LGA, interpregnancy BMI loss did not result in a decreased risk of perinatal complications. In this study, women of normal weight who gain weight before pregnancy were identified as a high-risk population for perinatal complications. This emphasizes that weight management is important for women of all BMI categories and a pregnancy wish.

Association of Overweight and Obesity Development Between Pregnancies With Stillbirth and Infant Mortality in a Cohort of Multiparous Women

OBJECTIVE

To identify the association of newly developed prepregnancy overweight and obesity with stillbirth and infant mortality.

METHODS

We studied subsequent pregnancies of mothers who were normal weight at fertilization of their first identified pregnancy, from a population-based cohort that linked birth registry with death records in Pennsylvania, 2003-2013. Women with newly developed prepregnancy overweight and obesity were defined as those whose body mass index (BMI) before second pregnancy was between 25 and 29.9 or 30 or higher, respectively. Our main outcomes of interest were stillbirth (intrauterine death at 20 weeks of gestation or greater), infant mortality (less than 365 days after birth), neonatal death (less than 28 days after birth) and postneonatal death (29-365 days after birth). Associations of both prepregnancy BMI categories and continuous BMI with each outcome were estimated by nonparametric targeted minimum loss-based estimation and inverse-probability weighted dose-response curves, respectively, adjusting for race-ethnicity, smoking, and other confounders (eg, age, education).

RESULTS

A cohort of 212,889 women were included for infant mortality analysis (192,941 women for stillbirth analysis). The crude rate of stillbirth and infant mortality in these final analytic cohorts were 3.3 per 1,000 pregnancies and 2.9 per 1,000 live births, respectively. Compared with women who stayed at a normal weight in their second pregnancies, those becoming overweight had 1.4 (95% CI 0.6-2.1) excess stillbirths per 1,000 pregnancies. Those becoming obese had 3.6 (95% CI 1.3-5.9) excess stillbirths per 1,000 pregnancies and 2.4 (95% CI 0.4-4.4) excess neonatal deaths per 1,000 live births. There was a dose-response relationship between prepregnancy BMI increases of more than 2 units and increased risk of stillbirth and infant mortality. In addition, BMI increases were associated with higher risks of infant mortality among women with shorter interpregnancy intervals (less than 18 months) compared with longer intervals.

CONCLUSION

Transitioning from normal weight to overweight or obese between pregnancies was associated with an increased risk of stillbirth and neonatal mortality.

Longitudinal Study of Maternal BMI in Successive Pregnancies

OBJECTIVE

This longitudinal observational study examined BMI changes between successive pregnancies.

METHODS

The computerized medical records of women who attended a large maternity hospital between 2009 and 2017 for their first and second singleton deliveries were analyzed. Women who had their weight first measured after 15 weeks of gestation in either pregnancy were excluded.

RESULTS

Of the 9,724 women, the incidence of obesity increased from 11.6% in the first pregnancy to 16.0% in the second. The mean interpregnancy interval was 32.5 ± 15.7 months, and median BMI change was +0.6 kg/m² (interquartile range 2.2; P < 0.001). Overall, 10.3% (1,006/9,724) developed overweight and 5.9% (571/9,724) developed obesity by the second pregnancy. Of the nulliparas in the overweight category, 20.6% (526/2,558) entered the obesity category. The development of obesity by the second pregnancy was independently associated with a longer interpregnancy interval, formula feeding at hospital discharge, taking antidepressants or anxiolytics, and postnatal depression. Professional/managerial employment was associated with a lower odds ratio of developing obesity.

CONCLUSIONS

Maternal obesity increased between the first and second pregnancy, with one-fifth of nulliparas in the overweight category developing obesity. Pregnancy-related factors were identified as predictors of developing obesity. Further research is needed to assess whether interventions targeting these related factors could optimize maternal weight management between pregnancies.

Maternal interpregnancy weight change and premature birth: Findings from an English population-based cohort study

Background

The relationship between maternal weight change between pregnancies and premature birth is unclear. This study aimed to investigate whether interpregnancy weight change between first and second, or second and third pregnancy is associated with premature birth.

Methods

Routinely collected data from 2003 to 2018 from one English maternity centre was used to produce two cohorts. The primary cohort (n = 14,961 women) consisted of first and second live-birth pregnancies. The secondary cohort (n = 5,108 women) consisted of second and third live-birth pregnancies. Logistic regression models were used to examine associations between interpregnancy BMI change and premature births adjusted for confounders. Subgroup analyses were carried out, stratifying by initial pregnancy BMI groups and analysing spontaneous and indicated premature births separately.

Results

In the primary cohort, 3.4% (n = 514) of births were premature compared to 4.2% (n = 212) in the secondary cohort, with fewer indicated than spontaneous premature births in both cohorts.

Primary cohort

Weight loss (>3kg/m²) was associated with increased odds of premature birth (adjusted odds ratio (aOR):3.50, 95% CI: 1.78–6.88), and spontaneous premature birth (aOR: 3.34, 95%CI: 1.60–6.98), in women who were normal weight (BMI 18.5-25kg/m²) at first pregnancy. Weight gain >1kg/m² was not associated with premature birth regardless of starting BMI.

Secondary cohort

Losing >3kg/m² was associated with increased odds of premature birth (aOR: 2.01, 95%CI: 1.05–3.87), when analysing the whole sample, but not when restricting the analysis to women who were overweight or obese at second pregnancy.

Conclusions

Normal-weight women who lose significant weight (>3kg/m²) between their first and second live pregnancies have greater odds of premature birth compared to normal-weight women who remain weight stable in the interpregnancy period. There was no evidence of association between weight change in women who were overweight or obese at the start of their first pregnancy and premature birth.

Effect of interpregnancy weight change on perinatal outcomes: systematic review and meta-analysis

Background

Although obesity is a well-known risk factor for adverse pregnancy outcomes, evidence is sparse about the effects of interpregnancy weight change on the risk of adverse perinatal complications in a subsequent pregnancy. The current study aims to assess the effect of interpregnancy weight change on the risk of developing gestational diabetes, pre-eclampsia, pregnancy induced hypertension, preterm birth, or delivering a large- or small-for-gestational age neonate.

Methods

Pubmed, Ovid Embase, ClinicalTrial.gov and the Cochrane library were systematically searched up until July 24th, 2019. Interpregnancy weight change was defined as the difference between pre-pregnancy weight of an index pregnancy and a consecutive pregnancy. Inclusion criteria included full text original articles reporting quantitative data about interpregnancy weight change in multiparous women with any time interval between consecutive births and the risk of any perinatal complication of interest. Studies reporting adjusted odds ratios and a reference group of − 1 to + 1 BMI unit change between pregnancies were harmonised by meta-analysis.

Results

Twenty-three cohort studies identified a total of 671,906 women with two or more consecutive pregnancies. Seven of these studies were included in the meta-analysis (280,672 women). Interpregnancy weight gain was consistently associated with a higher risk of gestational diabetes, pre-eclampsia, pregnancy induced hypertension and large-for-gestational age births. In contrast, interpregnancy weight loss was associated with a lower risk of delivering a large-for-gestational age neonate. The effect magnitude (relative risk) of interpregnancy weight gain on pregnancy induced hypertension or delivering a large-for-gestational age neonate was greater among women with a normal BMI in the index pregnancy compared to women with a starting BMI ≥25 kg/m².

Conclusion

These findings confirm that interpregnancy weight change impacts the risk of developing perinatal complications in a subsequent pregnancy. This provides evidence in support of guidelines encouraging women to achieve post-partum weight loss, as their risk of perinatal complications might be minimised if they return to their pre-pregnancy weight before conceiving again.

Prospectively registered with PROSPERO (CRD42017067326).

A new customised placental weight standard redefines the relationship between maternal obesity and extremes of placental size and is more closely associated with pregnancy complications than an existing population standard

Placental weight is a valuable indicator of its function, predicting both pregnancy outcome and lifelong health. Population-based centile charts of weight-for-gestational-age and parity are useful for identifying extremes of placental weight but fail to consider maternal size. To address this deficit, a multiple regression model was fitted to derive coefficients for predicting normal placental weight using records from healthy pregnancies of nulliparous/multiparous women of differing height and weight (n = 107,170 deliveries, 37-43 weeks gestation). The difference between actual and predicted placental weight generated a z-score/individual centile for the entire cohort including women with pregnancy complications (n = 121,591). The association between maternal BMI and placental weight extremes defined by the new customised versus population-based standard was investigated by logistic regression, as was the association between low placental weight and pregnancy complications. Underweight women had a greater risk of low placental weight [<10thcentile, OR 1.84 (95% CI 1.66, 2.05)] and obese women had a greater risk of high placental weight [>90th centile, OR 1.98 (95% CI 1.88, 2.10)] using a population standard. After customisation, the risk of high placental weight in obese/morbidly obese women was attenuated [OR 1.17 (95% CI 1.09, 1.25)]/no longer significant, while their risk of low placental weight was 59%-129% higher (P < 0.001). The customised placental weight standard was more closely associated with stillbirth, hypertensive disease, placental abruption and neonatal death than the population standard. Our customised placental weight standard reveals higher risk of relative placental growth restriction leading to lower than expected birthweights in obese women, and a stronger association between low placental weight and pregnancy complications generally. Further, it provides an alternative tool for defining placental weight extremes with implications for the placental programming of chronic disease.

An association between maternal weight change in the year before pregnancy and infant birth weight: ELFE, a French national birth cohort study

BACKGROUND

Weight-control interventions in pregnant women with overweight or obesity have limited effectiveness for fetal growth and birth outcomes. Interventions or prevention programs aiming at the pre-pregnancy period should be considered. However, how the woman's weight change before pregnancy affects fetal growth is not known. We investigated the association between weight change over the year before pregnancy and birth weight.

METHODS AND FINDINGS

We used the inclusion data of 16,395 women from the ELFE French national birth cohort, a nationally representative cohort in which infants were enrolled at birth with their families in 2011. Maternal weight change was self-reported and classified into 3 groups: moderate weight variation or stable weight, weight loss > 5 kg, and weight gain > 5 kg or both weight loss and gain > 5 kg. Multiple linear regression models were used to investigate the association between pre-pregnancy weight change and a birth weight z-score calculated according to the French Audipog reference, adjusted for a large set of maternal characteristics. The analyses were stratified by maternal body mass index (BMI) at conception (<25 versus ≥25 kg/m2) and adjusted for BMI within these categories. We used the MacKinnon method to test the mediating effect of gestational weight gain (GWG) on these associations. Mother's mean age was 30.5 years, 87% were born in France, and 26% had overweight or obesity. For women in either BMI category at conception, GWG was more than 2 kg higher, on average, for women with weight loss before pregnancy than for women with stable weight or moderate weight variation. For women with BMI < 25 kg/m2 at conception, birth weight was significantly higher with weight loss than stable weight before pregnancy (β = 0.08 [95% CI 0.02; 0.14], p = 0.01), and this total effect was explained by a significant mediating effect through GWG. For women with BMI ≥ 25 kg/m2 at conception, birth weight was not associated with pre-pregnancy weight loss during the year before pregnancy. Mediation analysis revealed that in these women, the direct effect of pre-pregnancy weight loss that would have resulted in a smaller birth weight z-score (β = -0.11 [95% CI -0.19; -0.03], p = 0.01) was cancelled out by the GWG. The mediating effect of GWG was even higher when weight loss resulted from a restrictive diet in the year before pregnancy. Weight gain before pregnancy was not associated with birth weight. Although we included a large number of women and had extensive data, the only potential cause of pre-pregnancy weight loss that was investigated was dieting for intentional weight loss. We have no information on other potential causes but did however exclude women with a history of pre-pregnancy chronic disease. Another limitation is declaration bias due to self-reported data.

CONCLUSIONS

Health professionals should be aware that GWG may offset the expected effect of weight loss before conception on fetal growth in overweight and obese women. Further studies are required to understand the underlying mechanisms in order to develop weight-control interventions and improve maternal periconceptional health and developmental conditions for the fetus.

Is maternal weight gain between pregnancies associated with risk of large-for-gestational age birth? Analysis of a UK population-based cohort

OBJECTIVE

Maternal overweight and obesity during pregnancy increases the risk of large-for-gestational age (LGA) birth and childhood obesity. We aimed to investigate the association between maternal weight change between subsequent pregnancies and risk of having a LGA birth.

DESIGN

Population-based cohort.

SETTING

Routinely collected antenatal healthcare data between January 2003 and September 2017 at University Hospital Southampton, England.

PARTICIPANTS

Health records of women with their first two consecutive singleton live-birth pregnancies were analysed (n=15 940).

PRIMARY OUTCOME MEASURE

Risk of LGA, recurrent LGA and new LGA births in the second pregnancy.

RESULTS

Of the 15 940 women, 16.0% lost and 47.7% gained weight (≥1 kg/m²) between pregnancies. A lower proportion of babies born to women who lost ≥1 kg/m² (12.4%) and remained weight stable between -1 and 1 kg/m² (11.9%) between pregnancies were LGA compared with 13.5% and 15.9% in women who gained 1-3 and ≥3 kg/m², respectively. The highest proportion was in obese women who gained ≥3 kg/m² (21.2%). Overweight women had a reduced risk of recurrent LGA in the second pregnancy if they lost ≥1 kg/m² (adjusted relative risk (aRR) 0.69, 95% CI 0.48 to 0.97) whereas overweight women who gained ≥3 kg/m² were at increased risk of new LGA after having a non-LGA birth in their first pregnancy (aRR 1.35, 95% CI 1.05 to 1.75). Normal-weight women who gained weight were also at increased risk of new LGA in the second pregnancy (aRR 1.26, 95% CI 1.06 to 1.50 with gain of 1-3 kg/m² and aRR 1.34, 95% CI 1.09 to 1.65 with gain of ≥3 kg/m²).

CONCLUSIONS

Losing weight after an LGA birth was associated with a reduced LGA risk in the next pregnancy in overweight women, while interpregnancy weight gain was associated with an increased new LGA risk. Preventing weight gain between pregnancies is an important measure to achieve better maternal and offspring outcomes.

Interpregnancy weight change and perinatal outcomes: A protocol for a systematic review and meta-analysis

BACKGROUND

Growing evidence suggests that interpregnancy weight change (IPWC) is a risk factor for perinatal outcomes, since it may increase the probability of gestational complications including gestational diabetes or cesarean delivery. Additionally, IPWC may affect neonatal outcomes increasing the prevalence of newborns small for gestational age or preterm birth. However, the association between IPWC and perinatal outcomes has not systematically synthesized thus far. This study protocol aims to provide a clear, transparent and standardized procedure for systematically reviewing the association between IPWC and perinatal outcomes.

METHODS AND ANALYSIS

This systematic review and meta-analyses protocol is based on the preferred reporting items for systematic review and meta-analysis protocols and the Cochrane Collaboration Handbook. MEDLINE, EMBASE, the Cochrane Library, and Web of Science will be systematically searched from their inception. No limits will be defined by study design, as such different tools to assess risk of bias will be used:Odd ratios and their corresponding 95% confidence intervals will be reported to evaluate associations between IPWC and perinatal outcomes.

RESULTS

The results of this study will be published in a peer-reviewed journal.

CONCLUSION

This systematic review and meta-analysis will systematically synthesize the evidence regarding the association between IPWC and perinatal outcomes. Data will be extracted from published articles and findings will be published in peer-reviewed journals. Ethical approval and informed consent will not be required due to the nature of the study.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018100449.

Placental metal concentrations in relation to placental growth, efficiency and birth weight

The quality of the intrauterine environment, in which the placenta plays a critical role, affects birth outcomes and lifelong health. The effect of metal contaminants on the growth and functioning of the placenta have not been widely reported but may provide insights into how metal exposures lead to these outcomes. We examined relationships between placental concentrations of cadmium (Cd), arsenic (As), mercury (Hg) and lead (Pb) and measures of placental growth and functioning (placental weight, placental efficiency (the log ratio of placental weight and birth weight), chorionic disc area and disc eccentricity) as part of the New Hampshire Birth Cohort Study (N = 1159). We additionally examined whether these associations were modified by placental concentrations of essential elements zinc (Zn) and selenium (Se). Associations were evaluated using generalized linear models. Multivariable-adjusted differences in placental weight were - 7.81 g (95% CI: -15.42, -2.48) with every ng/g increase in the Cd concentration of placenta (p-Value = 0.0009). Greater decrements in placental weight and efficiency associated with placental Cd were observed for females. For placentae with below median Zn and Se concentrations, decrements in placental weight were - 8.81 g (95% CI: -16.85, -0.76) and - 13.20 g (95% CI: -20.70, -5.70) respectively. The Cd concentration of placenta was also associated with reductions in placental efficiency both overall, and in Zn- and Se-stratified models. No appreciable differences were observed with other elements (As, Hg or Pb) and with other placental measures (chorionic disc area and disc eccentricity). In structural equation models, placental weight was a mediator in the relation between placental Cd concentration and reduced birth weight. Our findings suggest a role of interacting essential and contaminant elements on birth weight that may be mediated by changes in the growth and function of the placenta.

Interpregnancy change in body mass index and infant outcomes in Texas: a population-based study

Background

Maternal prepregnancy body mass index (BMI) is associated with several infant outcomes, but it is unclear whether these associations reflect causal relationships. We conducted a study of interpregnancy change in BMI (IPC-BMI) to improve understanding of the associations between BMI and large for gestational age (LGA), small for gestational age (SGA), and preterm birth (PTB).

Methods

Birth certificate data from 2481 linked sibling pairs (Texas, 2005–2012) were used to estimate IPC-BMI and evaluate its association with LGA, SGA, and PTB in the younger sibling of the pair. Multivariable logistic regression was used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI) using data from the full sample and within strata defined by prepregnancy BMI for the older sibling.

Results

On average, women gained 1.1 BMI units between pregnancies. In the full sample, interpregnancy BMI decreases were associated with reduced odds of LGA and increased odds of SGA and PTB (IPC-BMI < -1 versus 0 to < 1: LGA aOR 0.7, 95% CI 0.4, 1.1; SGA aOR 1.6, 95% CI 1.0, 2.7; PTB aOR 1.9, 95% CI 1.3, 2.8). In stratified analyses, similar associations were observed in some, but not all, strata. Findings for interpregnancy BMI increases were less consistent, with little evidence for associations between these outcomes and the most extreme IPC-BMI increases.

Conclusions

There is growing evidence that interpregnancy BMI decreases are associated with LGA, SGA, and PTB. However, taken as a whole, the literature provides insufficient evidence to establish causal links between maternal BMI and these outcomes.

Differential effects of high-fat diets before pregnancy and/or during pregnancy on fetal growth development

AIMS

The aim of the study was to investigate the effects of high-fat diets before pregnancy and/or during pregnancy on fetal development.

MAIN METHODS

Female mice were fed with standard diets (SD) or high-fat diets (HFD). After 12 weeks, females were mated. In the SD + SD and HFD + SD groups, pregnant mice were fed with standard diets. In the SD + HFD and HFD + HFD groups, pregnant mice were fed with high-fat diets. All pregnant mice were sacrificed on gestational day (GD) 16.

KEY FINDINGS

Fetal weight and crown-rump length were increased in SD + HFD-fed mice, whereas were decreased in HFD + SD-fed mice. The levels of CRP and TNF-α in maternal serum and amniotic fluid were elevated in all HFD-fed mice. Placenta weight was elevated in SD + HFD-fed but not in HFD + SD-fed mice. Blood sinusoid areas, and the number of Ki67-positive cells, a marker of cell proliferation, were elevated in placental labyrinth layer of SD + HFD-fed mice, but decreased in HFD + SD-fed mice. Finally, placental Fatp1, a fatty acid transporter gene, was up-regulated in SD + HFD-fed mice. By contrary, placental Fatp1, and Snat2, an amino acid transporter, were down-regulated in HFD + SD-fed mice. Moreover, the levels of placental FATP4 and SNAT2 were up-regulated in SD + HFD-fed mice.

SIGNIFICANCE

HFD before pregnancy and HFD during pregnancy differentially disturb fetal growth development. HFD before pregnancy-induced fetal SGA might be partially attributed to inflammatory cytokines and mediators derived from maternal adipose tissue. By contrary, HFD during pregnancy-induced fetal overweight may be partially attributed to the increase of placental nutrient transport capacity.

Weight loss after pregnancy: challenges and opportunities

It is important to pay attention to weight management before and between pregnancies, as women have an increased risk of weight gain during the reproductive years. Having a baby is a life-changing event for women and the challenge of weight management amidst this period of major physiological, psychological and social change should not be underestimated. However, the postpartum period offers an opportune time for lifestyle interventions, as women may have heightened awareness of their own and their wider families' health. Systematic reviews indicate that interventions including both diet and physical activity along with individualised support and self-monitoring are more likely to be successful in promoting postpartum weight loss. However, high levels of attrition and poor engagement have been an issue in previous trials in this area. Since postpartum women are difficult to reach and retain, future research must consider how to make weight-management interventions an attractive and attainable proposition for women who are juggling multiple, competing demands on their time. Ideally, intervention approaches need to be flexible and allow sustained contact with women, to facilitate a focus on maintenance of weight loss, as well as opportunities for re-engagement after life events that may disrupt weight-management progress. Using technology to deliver or support interventions holds promise but trials are needed to generate a range of appealing, effective and scalable options for postpartum women. What works at other life stages may not necessarily work here owing to specific barriers to weight management encountered in the postpartum period.

Interpregnancy weight change and adverse pregnancy outcomes: a systematic review and meta-analysis

OBJECTIVES

To evaluate the effect of interpregnancy body mass index (BMI) change on pregnancy outcomes, including large-for-gestational-age babies (LGA), small-for-gestational-age babies (SGA), macrosomia, gestational diabetes mellitus (GDM) and caesarean section (CS).

DESIGN

Systematic review and meta-analysis of observational cohort studies.

DATA SOURCES

Literature searches were performed across Cochrane, MEDLINE, EMBASE, CINAHL, Global Health and MIDIRS databases.

STUDY SELECTION

Observational cohort studies with participants parity from 0 to 1.

MAIN OUTCOME MEASURES

Adjusted ORs (aORs) with 95% CIs were used to evaluate the association between interpregnancy BMI change on five outcomes.

RESULTS

925 065 women with singleton births from parity 0 to 1 were included in the meta-analysis of 11 studies selected from 924 identified studies. A substantial increase in interpregnancy BMI (>3 BMI units) was associated with an increased risk of LGA (aOR 1.85, 95% CI 1.71 to 2.00, p<0.001), GDM (aOR 2.28, 95% CI 1.97 to 2.63, p<0.001), macrosomia (aOR 1.54, 95% CI 0.939 to 2.505) and CS (aOR 1.72, 95% CI 1.32 to 2.24, p<0.001) compared with the reference category, and a decreased risk of SGA (aOR 0.83, 95% CI 0.70 to 0.99, p=0.044). An interpregnancy BMI decrease was associated with a decreased risk of LGA births (aOR 0.70, 95% CI 0.55 to 0.90, p<0.001) and GDM (aOR 0.80, 95% CI 0.62 to 1.03), and an increased risk of SGA (aOR 1.31, 95% CI 1.06 to 1.63, p=0.014). Women with a normal BMI (<25kg/m2) at first pregnancy who have a substantial increase in BMI between pregnancies had a higher risk of LGA (aOR 2.10, 95% CI 1.93 to 2.29) and GDM (aOR 3.10, 95% CI 2.74 to 3.50) when compared with a reference than women with a BMI ≥25 kg/m2 at first pregnancy.

CONCLUSIONS

Gaining weight between pregnancies increases risk of developing GDM, CS and LGA, and reduces risk of SGA in the subsequent pregnancy. Losing weight between pregnancies reduces risk of GDM and LGA and increases risk of SGA. Weight stability between first and second pregnancy is advised in order to reduce risk of adverse outcomes.

TRIAL REGISTRATION NUMBER

CRD42016041299.

Influence of serum HMW adiponectin level in patients with pregnancy-induced hypertension syndrome on the occurrence of eclampsia in secondary pregnancy

In the present study, we studied the influence of serum high-molecular weight adiponectin (HMWA) levels in patients with pregnancy-induced hypertension (PIH) on the occurrence of eclampsia in secondary pregnancy and its related mechanisms. In total, 130 patients who were diagnosed with PIH for the first time were selected for this study; the median interval of the secondary pregnancy was 28.5 months. The serum HMWA and leptin levels both times were detected, and the insulin resistance indexes (HOMA-IR) were calculated. The serum inflammatory indexes in the secondary pregnancy included interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels, and the oxidative stress indexes included methane dicarboxylic aldehyde (MDA) and oxidized low-density lipoprotein (ox-LDL) levels. The expression levels of adiponectin receptor 2 and cyclooxygenase-2 (COX-2) in placental tissue were detected. In secondary pregnancy, there were a total of 20 cases of eclampsia (15.38%), including 2 cases of mild PIH, 8 cases of moderate PIH and 10 cases of severe PIH; differences were statistically significant when compared to patients without eclampsia (p<0.001). The serum HMWA levels in patients with severe PIH in the first pregnancy were significantly lower than those in patients with mild and moderate PIH, and the serum levels in patients with mild PIH were the highest. The leptin levels in patients with severe PIH were significantly higher than those in patients with mild and moderate PIH, and the leptin levels in patients with mild PIH were the lowest (p<0.05). The HMWA levels in patients with eclampsia in the secondary pregnancy was significantly lower than those in patients without eclampsia, and the leptin levels in patients with eclampsia were significantly increased. The HMWA levels in patients with eclampsia in the secondary pregnancy were lower than that in the first pregnancy, whereas the leptin levels were higher than that in the first pregnancy (p<0.05). HOMA-IR, IL-6, TNF-α, MDA and ox-LDL levels in patients with eclampsia were significantly higher than those in patients without eclampsia (p<0.05), and the adiponectin receptor 2 and COX-2 expression levels in the placental tissue were significantly higher than those in patients without eclampsia (p<0.05). Therefore, the serum HMWA levels are closely related to the occurrence of eclampsia in PIH patients in secondary pregnancy, and it influences insulin resistance, inflammatory response and oxidative stress response, which is correlated with increased adiponectin receptor 2 and COX-2 protein expression in placental tissue. Consequently, HMWA may be an important target for the intervention of preventing eclampsia for PIH patients in secondary pregnancy.

Interpregnancy weight change and adverse maternal outcomes: a retrospective cohort study

PURPOSE

Examine associations between interpregnancy body mass index (BMI) change (difference in the pre-pregnancy BMIs of two consecutive pregnancies) and gestational diabetes mellitus (GDM), pre-eclampsia (PE), gestational hypertension (GHtn), primary cesarean delivery, and vaginal birth after cesarean delivery (VBAC).

METHODS

Modified Poisson regression models estimated adjusted associations.

RESULTS

Every 1-unit increase in interpregnancy BMI increased risks of GDM (relative risk [RR]: 1.09; 95% confidence interval [CI], 1.07-1.11), PE (RR: 1.06; 95% CI, 1.04-1.09), GHtn (RR: 1.08; 95% CI, 1.06-1.10), and primary cesarean delivery (RR: 1.03; 95% CI, 1.01-1.05) and decreased the risk of a successful VBAC (RR: 0.98; 95% CI: 0.97-0.997) in the second pregnancy. A BMI increase of ≥3 units increased risks of GDM (RR: 1.71, 95% CI, 1.52-1.93), PE (RR: 1.60, 95% CI, 1.33-1.94), GHtn (RR: 1.66, 95% CI, 1.42-1.94), and primary cesarean delivery (RR: 1.29, 95% CI, 1.12-1.49) and decreased the risk of a successful VBAC (RR: 0.89; 95% CI, 0.80-0.99) compared to women with interpregnancy BMI change within -1 and +1 unit. GDM was also increased among women increasing their BMI by ≥2 but <3 units (RR: 1.40; 95% CI, 1.21-1.61) and among those gaining ≥1 but <2 units (RR: 1.23; 95% CI, 1.08-1.40).

CONCLUSION

An interpregnancy BMI increase of ≥3 units is associated with an increased risk of all outcomes. These findings emphasize the importance of interpregnancy weight management.

Association of Childhood Obesity and the Immune System: A Systematic Review of Reviews

The growing prevalence of childhood obesity has become a serious health problem over the past decades. As the immune system is greatly affected by excess weight, in this review of reviews, we discuss the findings of review articles about the relationship between childhood/maternal obesity and children's immune system. We searched English-language articles in PubMed, Scopus, ISI Thomson Reuters, and Google Scholar databases. All relevant reviews, either systematic or narrative, were retrieved. Then their quality was assessed by using the Assessment of Multiple Systematic Reviews and International Narrative Systematic Assessment tools, respectively. In the final step, 26 reviews were included. Our review suggests that childhood obesity is associated with extensive changes in the serum levels of inflammatory and anti-inflammatory cytokines and proteins, as well as the number of immune cells and their behavior. Therefore, it might cause or exacerbate diseases such as asthma, allergy, atopic dermatitis (AD), and obstructive sleep apnea syndrome. Moreover, childhood obesity may reduce the immune system responsiveness to vaccines and microorganisms. Furthermore, studies suggest that maternal obesity increases the risk of asthma in offspring. Future studies are needed to determine different associations of childhood obesity with allergy, atophic dermatitis, and autoimmune diseases.

Weight change across the start of three consecutive pregnancies and the risk of maternal morbidity and SGA birth at the second and third pregnancy

BACKGROUND

Weight-change across parities and/or current BMI may influence maternal and fetal morbidity and requires to be differentiated to better inform weight-management guidance.

METHODS

Direction, pattern and magnitude of weight-change across three consecutive parities and thereby two inter-pregnancy periods was described in 5079 women. The association between inter-pregnancy weight-change versus current BMI and adverse maternal events, SGA-birth and preterm delivery at second and third pregnancy were investigated by logistic regression.

RESULTS

More women gained weight across the defined childbearing period than lost it, with ~35% of normal and overweight women gaining sufficient weight to move up a BMI-category. Nine patterns of weight-change were defined across two inter-pregnancy periods and 50% of women remained weight-stable throughout (within 2BMI units/period). Women who were overweight/obese at first pregnancy had higher risk of substantial weight-gain and loss (>10kg) during each of two inter-pregnancy periods. Inter-pregnancy weight-gain (> 2BMI units) between first and second pregnancy increased the risk of maternal morbidity (1or more event of hypertensive disease, caesarean-section, thromboembolism) at second pregnancy, while weight-loss (>2BMI units) increased the risk of SGA-birth. Similarly, increased risk of maternal morbidity at the third pregnancy was influenced by weight-gain during both inter-pregnancy periods but not by current BMI-category. Both weight-gain between first and second pregnancy, and being overweight/obese by third pregnancy protected the fetus against SGA-birth whereas weight-loss between second and third pregnancy doubled the SGA risk.

CONCLUSION

Half the women studied exhibited significant weight-fluctuations. This influenced their risk of maternal morbidity and SGA-birth at second and third pregnancy.

Interpregnancy weight changes and impact on pregnancy outcome in a cohort of women with a macrosomic first delivery: a prospective longitudinal study

OBJECTIVE

To determine the median interpregnancy maternal weight change between first and second pregnancies, and second and third pregnancies and to assess the impact of this weight change on pregnancy outcome in a cohort of women with a macrosomic first delivery.

STUDY DESIGN

Prospective longitudinal study conducted over three pregnancies from 2007 to 2015.

SETTING

Tertiary referral maternity hospital, Dublin, Ireland.

PARTICIPANTS

Women were recruited if their first baby weighed >4.0 kg.

METHODS

The pregnancy outcomes in the second and third pregnancies were analysed separately. Data were also analysed for both interpregnancy intervals comparing outcomes for those who gained any weight, or more weight than the median, with those who did not.

MAIN OUTCOME MEASURES

Recurrent fetal macrosomia ≥4.0 kg and gestational diabetes mellitus.

RESULTS

There were 280 women who delivered a third baby between 2011 and 2015. There were no differences in pregnancy outcomes for the second pregnancy in women who gained interpregnancy weight compared with those who did not and those who gained more interpregnancy weight than the median compared with those who did not. There was a statistically significant increase in birth weight ≥4.0 kg (54.0% vs 39.6% p=0.03) in those women who gained any weight between the second and third pregnancies. In those women who gained more interpregnancy weight than the median (1.70 kg) between a second and third pregnancy, there was a significant increase in the rate of gestational diabetes (6.5% vs 1.4%, p=0.03).

CONCLUSIONS

This longitudinal study demonstrates that within this cohort maternal interpregnancy weight change between a second and third pregnancy is associated with an increase in birth weight ≥4.0 kg. Additionally, a gain of more weight than the median (1.70 kg) is associated with a higher rate of gestational diabetes.

Placental Origins of Chronic Disease

Epidemiological evidence links an individual's susceptibility to chronic disease in adult life to events during their intrauterine phase of development. Biologically this should not be unexpected, for organ systems are at their most plastic when progenitor cells are proliferating and differentiating. Influences operating at this time can permanently affect their structure and functional capacity, and the activity of enzyme systems and endocrine axes. It is now appreciated that such effects lay the foundations for a diverse array of diseases that become manifest many years later, often in response to secondary environmental stressors. Fetal development is underpinned by the placenta, the organ that forms the interface between the fetus and its mother. All nutrients and oxygen reaching the fetus must pass through this organ. The placenta also has major endocrine functions, orchestrating maternal adaptations to pregnancy and mobilizing resources for fetal use. In addition, it acts as a selective barrier, creating a protective milieu by minimizing exposure of the fetus to maternal hormones, such as glucocorticoids, xenobiotics, pathogens, and parasites. The placenta shows a remarkable capacity to adapt to adverse environmental cues and lessen their impact on the fetus. However, if placental function is impaired, or its capacity to adapt is exceeded, then fetal development may be compromised. Here, we explore the complex relationships between the placental phenotype and developmental programming of chronic disease in the offspring. Ensuring optimal placentation offers a new approach to the prevention of disorders such as cardiovascular disease, diabetes, and obesity, which are reaching epidemic proportions.

Adult Pre-pregnancy Weight Change and Risk of Developing Hypertensive Disorders in Pregnancy

BACKGROUND

While the association of pre-pregnancy body mass index (BMI) and hypertensive disorders in pregnancy (HDP) is well documented, little is known about the relationship between pre-pregnancy weight change and HDP. We examined the impact of adult pre-pregnancy weight change on the development of HDP.

METHODS

We included 2914 women, surveyed about every three years since 1996, from the 1973-78 cohort of the Australian Longitudinal Study on Women's Health. Women without hypertension or HDP were followed-up between 2003 and 2012. Generalised estimating equations were used to assess the effect of baseline BMI (mean age 20 years) and pre-pregnancy weight change on the incidence of HDP.

RESULTS

Over 9 years of follow up, 301 incident HDP cases (6.3%) were reported from 4813 pregnancies. Overweight and obese women at the baseline survey were 1.67 (95% CI 1.3, 2.2) and 2.15 (95% CI 1.4, 3.3) times more likely to develop HDP than normal weight women, respectively. Compared with stable weight women, women with small (>1.5-2.5%) or moderate/high (>2.5%) annual weight gain had elevated risk of HDP (RR 1.67 95% CI 1.3, 2.2; RR 2.31, 95% CI 1.8, 3.0, respectively). Women who reported annual weight loss (>1.5%) between baseline and the average age of 24 years were 46% (95% CI 0.4, 0.8) less likely to develop HDP.

CONCLUSIONS

Pre-pregnancy weight gain is associated with an increased risk of HDP, whereas early adult weight loss is associated with lower risk of HDP.

Pre-pregnancy body mass index and inter-pregnancy weight change among women of Russian, Somali and Kurdish origin and the general Finnish population

Objectives: We studied the differences in the mean pre-pregnancy body mass index (BMI) and mean inter-pregnancy weight change in women of Russian, Somali and Kurdish origin and women in the general Finnish population. Methods: The population-based samples were from the Migrant Health and Wellbeing Study and the Health 2011 Survey conducted in six cities in Finland in 2010–2012. This study included women with at least one birth in Finland. Data on their previous pregnancies in Finland were obtained from the National Medical Birth Register for 318 Russian, 584 Somali and 373 Kurdish origin women and for 243 women in the general Finnish population (reference group). Data on pre-pregnancy weight and height were self-reported in early pregnancy. Linear logistic regression was the main method of analysis. Results: The unadjusted mean pre-pregnancy BMI was higher in Somali (27.0 kg/m2, p<0.001) and Kurdish (25.8 kg/m2, p<0.001) women, but lower in Russian (22.2 kg/m2, p<0.001) women than in the reference group (24.1 kg/m2). The adjusted coefficients for the difference in the mean pre-pregnancy BMI were −1.93 (95% CI −2.77 to −1.09) for Russian, 1.82 (95% CI 0.89–2.75) for Somali and 1.30 (95% CI 0.43–2.17) for Kurdish women compared with the reference group. Among women with at least two births, no statistically significant difference was observed in the mean inter-pregnancy weight change between the migrant groups and the reference group. Conclusions: Somali and Kurdish women had higher mean pre-pregnancy BMIs than women in the general Finnish population and may need special support and health promotion strategies for weight management.

Obesity and pregnancy: mechanisms of short term and long term adverse consequences for mother and child

Obesity is the most common medical condition in women of reproductive age. Obesity during pregnancy has short term and long term adverse consequences for both mother and child. Obesity causes problems with infertility, and in early gestation it causes spontaneous pregnancy loss and congenital anomalies. Metabolically, obese women have increased insulin resistance in early pregnancy, which becomes manifest clinically in late gestation as glucose intolerance and fetal overgrowth. At term, the risk of cesarean delivery and wound complications is increased. Postpartum, obese women have an increased risk of venous thromboembolism, depression, and difficulty with breast feeding. Because 50-60% of overweight or obese women gain more than recommended by Institute of Medicine gestational weight guidelines, postpartum weight retention increases future cardiometabolic risks and prepregnancy obesity in subsequent pregnancies. Neonates of obese women have increased body fat at birth, which increases the risk of childhood obesity. Although there is no unifying mechanism responsible for the adverse perinatal outcomes associated with maternal obesity, on the basis of the available data, increased prepregnancy maternal insulin resistance and accompanying hyperinsulinemia, inflammation, and oxidative stress seem to contribute to early placental and fetal dysfunction. We will review the pathophysiology underlying these data and try to shed light on the specific underlying mechanisms.

Maternal Diet and Nutrient Requirements in Pregnancy and Breastfeeding. An Italian Consensus Document

The importance of lifestyle and dietary habits during pregnancy and breastfeeding, for health of mothers and their offspring, is widely supported by the most recent scientific literature. The consumption of a varied and balanced diet from the preconceptional period is essential to ensure both maternal well-being and pregnancy outcomes. However, the risk of inadequate intakes of specific micronutrients in pregnancy and lactation is high even in the most industrialized countries. This particularly applies to docosahexaenoic acid (DHA), iron, iodine, calcium, folic acid, and vitamin D, also in the Italian population. Moreover, the risk of not reaching the adequate nutrient supply is increased for selected groups of women of childbearing age: those following exclusion diets, underweight or overweight/obese, smokers, adolescents, mothers who have had multiple or close pregnancies, and those with previous unfavorable pregnancy outcomes.

Impact of inter-pregnancy BMI change on perinatal outcomes: a retrospective cohort study

OBJECTIVE

To examine the patterns and predictors of inter-pregnancy body mass index (BMI) change and its impact on perinatal outcomes in the second pregnancy.

DESIGN

Retrospective cohort study.

SETTING

Tertiary teaching hospital in Adelaide, Australia.

POPULATION

Women with their first and second consecutive, singleton deliveries occurring between 2000 and 2012 (N=5371).

METHODS

Inter-pregnancy weight change calculated based on difference between BMI at respective antenatal booking visits. Association between inter-pregnancy weight change and perinatal outcomes investigated using multivariate generalised linear models, with stratification according to initial maternal BMI category in first pregnancy.

MAIN OUTCOME MEASURES

Gestational diabetes (GDM); pregnancy induced hypertensive disorders; small-for-gestational age (SGA); preterm birth; large-for-gestational age (LGA) and macrosomia (>4500g).

RESULTS

On average, women with a normal BMI gained 1kg/m(2) between first and second pregnancies, while women who were overweight or obese gained 1.37kg/m(2). Among women with a normal BMI in their first pregnancy, a BMI increase of ≥4kg/m(2) was associated with increased risk of developing GDM (aRR 1.97; 95% CI 1.22-3.19), a macrosomic (aRR 4.06; 95% CI 2.25-7.34) or LGA infant (aRR 1.31 0.96-1.78) in the second pregnancy, while a reduction in BMI (≤-2kg/m(2)) was associated with an increased risk of SGA (aRR 1.94; 1.19-3.16). Among women who were overweight or obese in their first pregnancy, a BMI increase of ≥2-4 and ≥4kg/m(2) was associated with increased risks of developing GDM in the second pregnancy (aRR 1.39; 95% CI 1.01-1.91 and aRR 1.64 95% CI 1.16-2.31; ptrend<0.001), while no associations were observed for a BMI increase and risk of a macrosomic, SGA, or LGA infant. In contrast, reduction in BMI (≤-2kg/m(2)) was associated with a reduced risk of GDM (aRR 0.58 95% CI 0.37-0.90) and SGA (aRR 0.47; 95% CI 0.25-0.87).

CONCLUSION

Increases in BMI between pregnancies is associated with an increased risk for perinatal complications, even in normal-weight women, while a reduction in BMI is associated with improved perinatal outcomes among women who are overweight/obese. Inter-pregnancy weight control is an important target to reduce the risk of an adverse perinatal outcome in a subsequent pregnancy.

Inter-Pregnancy Weight Change and the Risk of Recurrent Pregnancy Complications

Women with specific adverse pregnancy outcomes in their first pregnancy may be receptive to inter-pregnancy weight management guidance aimed at preventing these complications reoccurring in subsequent pregnancies. Thus the association between inter-pregnancy weight change and the risk of recurrent pregnancy complications at the second pregnancy was investigated in a retrospective cohort study of 24,520 women with their first-ever and second consecutive deliveries in Aberdeen using logistic regression. Compared with women who were weight stable, weight loss (>2BMI units) between pregnancies was associated with an increased risk of recurrent small for gestational age (SGA) birth and elective Cesarean-section, and was protective against recurrent pre-eclampsia, placental oversize and large for gestational age (LGA) birth. Conversely weight gain (>2BMI units) between pregnancies increased the risk of recurrent gestational hypertension, placental oversize and LGA birth and was protective against recurrent low placental weight and SGA birth. The relationships between weight gain, and placental and birth weight extremes were evident only in women with a healthy weight at first pregnancy (BMI<25units), while that between weight gain and the increased risk of recurrent gestational hypertension was largely independent of first pregnancy BMI. No relationship was detected between inter-pregnancy weight change and the risk of recurrent spontaneous preterm delivery, labour induction, instrumental delivery, emergency Cesarean-section or postpartum hemorrhage. Therefor inter-pregnancy weight change impacts the risk of recurrent hypertensive disorders, SGA and LGA birth and women with a prior history of these specific conditions may benefit from targeted nutritional advice to either lose or gain weight after their first pregnancy.

Prepregnancy body mass index in a first uncomplicated pregnancy and outcomes of a second pregnancy

OBJECTIVE

This study examined the effect of body mass index (BMI) before a first uncomplicated pregnancy on maternal and fetal outcomes in a subsequent pregnancy, including preterm births, preeclampsia, cesarean delivery, small for gestational age, large for gestational age, and neonatal deaths.

STUDY DESIGN

We conducted a population-based cohort study (n = 121,092) using the Missouri maternally linked birth registry (1989 through 2005). Multivariable binary logistic regression models were fit to estimate odds ratios and 95% confidence intervals for the parameters of interest after controlling for sociodemographic and pregnancy-related confounders in the second pregnancy.

RESULTS

Compared to women with a normal BMI in their first pregnancy, those who were underweight prepregnancy had increased odds for preterm birth by 20% and small for gestational age by 40% in their second pregnancy, while those with prepregnancy obesity had increased odds for large for gestational age, preeclampsia, cesarean delivery, and neonatal deaths in their second pregnancy by 54%, 156%, 85%, and 37%, respectively.

CONCLUSION

Women starting a first pregnancy with suboptimal BMI may be at risk of adverse maternal and fetal outcomes in a subsequent pregnancy, even if their first pregnancy was uncomplicated or if they reached a normal weight by their second pregnancy. The long-term consequences of suboptimal BMI carry considerable public health implications.