Associations of Body Mass Index and Gestational Weight Gain with Term Pregnancy Outcomes

Plasticity of gastrointestinal vagal afferents in terms of feeding-related physiology and pathophysiology

Gastrointestinal vagal afferents play an important role in communicating food related information from the gut to the brain. This information initiates vago-vagal reflexes essential for gut functions, including gut motility and secretions. These afferents also play a role in energy homeostasis, signalling the arrival, amount and nutrient composition of a meal to the central nervous system where it is processed ultimately leading to termination of a meal. Vagal afferent responses to food related stimuli demonstrate a high degree of plasticity, responding to short term changes in nutritional demand, such as the fluctuations that occur across a 24-hr or in response to a fast, as well as long term changes in energy demand, such as occurs during pregnancy. This plasticity is disrupted in disease states, such as obesity or chronic stress where there is hypo- and hypersensitivity of these afferents, respectively. Improved understanding of the plasticity of these afferents will enable identification of new treatment options for diseases associated with vagal afferent function.

Association of serum leptin at 24-28 weeks gestation with initiation and progression of labor in women

Concentrations of the hormone leptin, which is produced by adipose tissue, increase with increasing BMI, whereas leptin sensitivity often declines with higher BMI. Thus, altered leptin signaling may play a role in reproductive health risks observed with increasing BMI, which include later onset and slow progression of labor. Conflicting evidence from clinical, animal and in vitro studies have suggested that leptin either promotes or inhibits labor. We hypothesized that serum leptin concentrations or serum leptin: body mass index (BMI) ratios in women may be associated with the initiation and progression of labor. Following informed consent, serum samples were collected from 90 women with singleton pregnancies at the time of routine glucose-challenge testing, for measurement of leptin. The potential influence of leptin on gestation length and cervical dilation timing were examined by multiple linear regression. Data were analyzed from 63 participants who met exclusion and inclusion criteria. Leptin concentrations (log-transformed) at 24–28 weeks gestation were not significantly correlated with first trimester BMI . Log serum leptin and leptin: BMI ratio each were significantly associated with shorter total gestation length in uncomplicated, term pregnancies. In contrast, the mid-pregnancy leptin concentrations were not associated with progression of labor, assessed by cervical dilation over time. The association between higher serum leptin and shorter gestation length is consistent with the hypothesis that leptin promotes, or is permissive for, the onset of labor.

Gestational Weight Gain Influences the Adipokine-Oxidative Stress Association during Pregnancy

INTRODUCTION AND OBJECTIVE

The weight gained during pregnancy could determine the immediate and future health of the mother-child dyad. Excessive gestational weight gain (EGWG) due to abnormal adipose tissue (AT) accumulation is strongly associated with adverse perinatal outcomes as gestational diabetes, macrosomia, obesity, and hypertension further in life. Dysregulation of adipokine, AT dysfunction, and an imbalance in the prooxidant-antioxidant systems are critical features in altered AT accumulation. This study was aimed to investigate the association between adipokines and oxidative stress markers in pregnant women and the influence of the GWG on this association.

METHODS

Maternal blood samples were obtained in the third trimester of pregnancy (n = 74) and serum adipokines (adiponectin, leptin, and resistin), oxidative damage markers: 8-oxo-2'-deoxyguanosine (8-oxodG), lipohydroperoxides (LOOH), malondialdehyde (MDA), and carbonylated proteins (CP), and glucose a metabolic marker were measured.

RESULTS

Women with EGWG had low adiponectin levels than women with adequate weight gain (AWG) or insufficient weight gain (IWG). Multiple linear regression models revealed a positive association between adiponectin and 8-oxodG in women with AWG (B = 1.09, 95% CI: 164-222, p = 0.027) and IWG (B = 0.860, 95% CI: 0.199-1.52, p = 0.013) but not in women with EGWG. In women with EGWG, leptin was positively associated with LOOH (p = 0.018), MDA (p = 0.005), and CP (p = 0.010) oxidative markers.

CONCLUSION

Our findings suggest that concurrent mechanisms regulate adipokine production and oxidative stress in pregnant women and that this regulation is influenced by GWG, probably due to an excessive AT accumulation.

Understanding how maternal social and biological factors are related to fetal growth in an urban South African cohort

The aim of this study was to identify social and biological drivers of fetal growth by examining associations with household, preconception, and pregnancy factors in a cohort from Soweto, South Africa. Complete data and ultrasound scans were collected on 519 women between 2013 and 2016 at 6 time points during pregnancy (<14, 14-18, 19-23, 24-28, 29-33 weeks, and 34-38 weeks). Household-level factors, preconception health, baseline body mass index (BMI), and demographic data were collected at the first visit. During pregnancy, gestational weight gain (GWG; kg/week) was calculated. At 24-28 weeks of gestation, oral glucose tolerance test was used to determine gestational diabetes mellitus (GDM) status, and hypertension status was characterised. Longitudinal growth in head circumference, abdominal circumference, biparietal diameter, and femur length were modelled using the Superimposition by Translation and Rotation, a shape-invariant model which produces growth curves against gestational age. A priori identified exposure variables were then included in a series of sex-stratified hierarchical regression models for each fetal growth outcome. No household-level factors were associated with fetal growth. Maternal BMI at baseline was positively associated with all outcome parameters in males and females. Both GWG (in males and females) and GDM (in males) were significant positive predictors of abdominal growth. Males showed more responsiveness to abdominal growth, while females were more responsive to linear growth. Thus, fetal growth was largely predicted by maternal biological factors, and sexual dimorphism in the responsiveness of fetal biometry to biological exposures was evident.

Gestational weight gain and gestational diabetes among Emirati and Arab women in the United Arab Emirates: results from the MISC cohort

Background

Nutritional status of women during pregnancy has been considered an important prognostic indicator of pregnancy outcomes.

Objectives

To investigate the pattern of gestational weight gain (GWG) and gestational diabetes mellitus (GDM) and their risk factors among a cohort of Emirati and Arab women residing in the United Arab Emirates (UAE). A secondary objective was to investigate pre-pregnancy body mass index (BMI) and its socio-demographic correlates among study participants.

Methods

Data of 256 pregnant women participating in the cohort study, the Mother-Infant Study Cohort (MISC) were used in this study. Healthy pregnant mothers with no history of chronic diseases were interviewed during their third trimester in different hospitals in UAE. Data were collected using interviewer-administered multi-component questionnaires addressing maternal sociodemographic and lifestyle characteristics. Maternal weight, weight gain, and GDM were recorded from the hospital medical records.

Results

Among the study participants, 71.1% had inadequate GWG: 31.6% insufficient and 39.5% excessive GWG. 19.1% reported having GDM and more than half of the participants (59.4%) had a pre-pregnancy BMI ≥ 25 kg/m². The findings of the multiple multinomial logistic regression showed that multiparous women had decreased odds of excessive gain as compared to primiparous [odds ratio (OR): 0.17; 95% CI: 0.05–0.54]. Furthermore, women with a pre-pregnancy BMI ≥ 25 kg/m² had increased odds of excessive gain (OR: 2.23; 95%CI: 1.00–5.10) as compared to those with pre-pregnancy BMI < 25 kg/m². Similarly, women who had a pre-pregnancy BMI ≥ 25 kg/m² were at higher risk of having GDM (OR: 2.37; 95%CI: 1.10–5.12). As for the associations of women’s characteristics with pre-pregnancy BMI, age and regular breakfast consumption level were significant predictors of higher pre-pregnancy BMI.

Conclusions

This study revealed alarming prevalence rates of inadequate, mainly excessive, GWG and GDM among the MISC participants. Pre-pregnancy BMI was found a risk factor for both of these conditions (GWG and GDM). In addition, age and regular breakfast consumption were significant determinants of pre-pregnancy BMI. Healthcare providers are encouraged to counsel pregnant women to maintain normal body weight before and throughout pregnancy by advocating healthy eating and increased physical activity in order to reduce the risk of excessive weight gain and its associated complications.

Incidence and Outcomes of Gestational Diabetes Mellitus Using the New International Association of Diabetes in Pregnancy Study Group Criteria in Hôpital Maisonneuve-Rosemont

OBJECTIVES

At 1 Canadian university hospital, pregnant women were routinely screened for gestational diabetes mellitus (GDM) with a 75-g oral glucose tolerance test (OGTT). Diagnostic plasma glucose thresholds were as follows: fasting: ≥5.3 mmol/L, 1 h: ≥10.6 mmol/L and 2 h: ≥9.0 mmol/L. In 2015, diagnostic thresholds were reduced to those recommended by the International Association of Diabetes in Pregnancy Study Group (IADPSG) as follows: fasting: ≥5.1 mmol/L, 1 h: ≥10.0 mmol/L and 2 h: ≥8.5 mmol/L. However, subsequent Diabetes Canada guidelines state that further evidence is required before recommending those thresholds. Our objectives were to compare pregnancy outcomes of all pregnant women who underwent a 75-g OGTT before and after the adoption of the IADPSG criteria.

METHODS

Pregnancy outcomes of all women (N=2,830) that had a pregnancy OGTT at the Hôpital Maisonneuve-Rosemont between July 1, 2014 and March 1, 2015 (pre-IADPSG group) were compared with women who were screened between March 1, 2015 and January 1, 2016 (post-IADPSG group). Medical files were reviewed to compare outcomes.

RESULTS

Women in the post-IADPSG group had a higher early body mass index (26.3 vs 25.5 kg/m², p=0.01) and more chronic hypertension (3.7% vs 1.2%, p<0.0001), respectively. OGTT results were similar, but rates of GDM were 10.8% (141 of 1,295) in the pre-IADPSG group and 17.6% (271 of 1,535) in the post-IADPSG group. In the post-IADPSG group, pre-eclampsia rates were lower (1.0% vs 2.2%, p=0.021), as was labour induction (25.6% vs 32.8%, p<0.0001) and neonatal intensive care unit admission (4.8% vs 8.5%, p<0.001), respectively.

CONCLUSIONS

Adopting IADPSG criteria for GDM improved pregnancy outcomes in our obstetric population.

Impact of parental weight status on children's body mass index in early life: evidence from a Chinese cohort

OBJECTIVES

To understand whether parents' weight status before conception predicts body mass index (BMI) of their offspring in early life and the differences between the mother-child and father-child associations.

DESIGN

A birth cohort study.

SETTING

Conducted at the Community Health Service Centre in Shenyang, Wuhan and Guangzhou.

PARTICIPANTS

A total of 2220 live birth newborns were recruited randomly after consent of their parents, and 1178 were followed up until 2 years old.

METHODS

Parental demographics, maternal characteristics during pregnancy, children's anthropometric data and feeding patterns at 1 month old were collected. BMI was calculated and BMI Z-scores (BMI_Z) were generated by referring to WHO growth standard. Parental weight status was categorised into underweight, normal weight, and overweight and obese according to the Working Group of Obesity in China. General linear models and generalised linear models were used to assess the associations between parents and offspring.

OUTCOME MEASURES

The primary outcomes were descriptive data on child's sex-specific anthropometric variables. The secondary outcomes were BMI_Z and weight status of children at each time point.

RESULTS

No gender difference was observed in BMI_Z or overweight or obesity rates from birth to 24 months old, although boys were significantly heavier and had a greater length/height than girls (P<0.05). The overweight and obesity rates of children peaked at 12 months old. Maternal BMI/weight status had a significant but small effect on BMI_Z at birth, but not on the paternal side. The impact of parental BMI on child's BMI_Z after birth was similar at each follow-up. Offspring with underweight mothers tend to have reduced BMI_Z after birth while overweight/obese fathers had children with a greater BMI_Z.

CONCLUSIONS

Maternal weight status had small effect on both fetal and child growth after birth. Significant but mild paternal influence was only detected after birth.