Low prenatal weight gain among adult WIC participants delivering term singleton infants: variation by maternal and program participation characteristics

Racial/ethnic variations in gestational weight gain: a population-based study in Ontario

Objective

To explore inadequate and excessive gestational weight gain (GWG) among pregnant women of different racial/ethnic backgrounds in Ontario, Canada.

Methods

A population-based retrospective cohort study was conducted among women who had prenatal screening and had a singleton birth in an Ontario hospital between April 2016 and March 2017. We estimated adjusted risk ratios (aRR) of racial/ethnic differences for inadequate or excessive GWG using multinomial logistic regression models. Interaction effects were examined to determine whether racial/ethnic difference in GWG varied by pre-pregnancy body mass index (BMI).

Results

Among 74,424 women, the prevalence of inadequate GWG in White, Asian, and Black women was 15.7%, 25.8%, and 25.0%, and excessive GWG was 62.8%, 45.5%, and 54.7%, respectively. There were significant interaction effects between race/ethnicity and pre-pregnancy BMI for inadequate GWG (Wald p < 0.01) and excessive GWG (Wald p < 0.01). Compared with White women, Asian women had higher risk of inadequate GWG and lower risk of excessive GWG in all weight classes, and Black women had higher risk of inadequate GWG and lower risk of excessive GWG if their BMI was normal, overweight, or obese.

Conclusion

Variations in unhealthy GWG by pre-pregnancy weight classes among Ontario White, Asian and Black women were observed. Individualized counseling regarding appropriate GWG is universally recommended. Additional consideration of racial/ethnic variations by maternal weight classes may help to promote healthy GWG in Canada.

Electronic supplementary material

The online version of this article (10.17269/s41997-019-00250-z) contains supplementary material, which is available to authorized users.

Racial/Ethnic Disparities in Inadequate Gestational Weight Gain Differ by Pre-pregnancy Weight

Pre-pregnancy body mass index (BMI) varies by race/ethnicity and modifies the association between gestational weight gain (GWG) and adverse pregnancy outcomes, which disproportionately affect racial/ethnic minorities. Yet studies investigating whether racial/ethnic disparities in GWG vary by pre-pregnancy BMI are inconsistent, and none studied nationally representative populations. Using categorical measures of GWG adequacy based on Institute of Medicine recommendations, we investigated whether associations between race/ethnicity and GWG adequacy were modified by pre-pregnancy BMI [underweight (<18.5 kg/m(2)), normal weight (18.5-24.9 kg/m(2)), overweight (25.0-29.9 kg/m(2)), or obese (≥30.0 kg/m(2))] among all births to Black, Hispanic, and White mothers in the 1979 USA National Longitudinal Survey of Youth cohort (n = 6,849 pregnancies; range 1-10). We used generalized estimating equations, adjusted for marital status, parity, smoking during pregnancy, gestational age, and multiple measures of socioeconomic position. Effect measure modification between race/ethnicity and pre-pregnancy BMI was significant for inadequate GWG (Wald test p value = 0.08). Normal weight Black [risk ratio (RR) 1.34, 95 % confidence interval (CI) 1.18, 1.52] and Hispanic women (RR 1.33, 95 % CI 1.15, 1.54) and underweight Black women (RR 1.38, 95 % CI 1.07, 1.79) experienced an increased risk of inadequate GWG compared to Whites. Differences in risk of inadequate GWG between minority women, compared to White women, were not significant among overweight and obese women. Effect measure modification between race/ethnicity and pre-pregnancy BMI was not significant for excessive GWG. The magnitude of racial/ethnic disparities in inadequate GWG appears to vary by pre-pregnancy weight class, which should be considered when designing interventions to close racial/ethnic gaps in healthy GWG.

Nutrient-restricted fetus and the cardio–renal connection in hypertensive offspring

A suboptimal intrauterine environment has a number of deleterious effects on fetal development and postpartum health outcomes. Epidemiological studies on several human populations have linked socioeconomic status and low birth weight to an increased incidence of diseases such as hypertension, diabetes, obesity and cardiovascular disease. A growing number of experimental studies in a variety of animal models demonstrate that maternal stressors, such as nutrition and reduced uterine perfusion, affect the intrauterine milieu and result in increased blood pressure in offspring. Several mechanisms appear to contribute to hypertension, including vascular dysfunction and increased peripheral resistance, altered cardio-renal structure and alterations in cardio-renal function. Although many studies have characterized models of developmentally generated hypertension, few have begun to seek therapeutic modalities to ameliorate its incidence. This review discusses recent work that refines hypotheses linking a suboptimal intrauterine environment to cardiovascular and renal phenotypes that have increased susceptibility to cardiovascular disease and hypertension.

Impact of increasing inter-pregnancy interval on maternal and infant health

Short inter-pregnancy intervals (IPIs) have been associated with adverse maternal and infant health outcomes in the literature. However, many studies in this area have been lacking in quality and appropriate control for confounders known to be associated with both short IPIs and poor outcomes. The objective of this systematic review was to assess this relationship using more rigorous criteria, based on GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology. We found too few higher-quality studies of the impact of IPIs (measured as the time between the birth of a previous child and conception of the next child) on maternal health to reach conclusions about maternal nutrition, morbidity or mortality. However, the evidence for infant effects justified meta-analyses. We found significant impacts of short IPIs for extreme preterm birth [<6 m adjusted odds ratio (aOR): 1.58 [95% confidence interval (CI) 1.40, 1.78], 6-11 m aOR: 1.23 [1.03, 1.46]], moderate preterm birth (<6 m aOR: 1.41 [1.20, 1.65], 6-11 m aOR: 1.09 [1.01, 1.18]), low birthweight (<6 m aOR: 1.44 [1.30, 1.61], 6-11 m aOR: 1.12 [1.08, 1.17]), stillbirth (aOR: 1.35 [1.07, 1.71] and early neonatal death (aOR: 1.29 [1.02, 1.64]) outcomes largely in high- and moderate-income countries. It is likely these effects would be greater in settings with poorer maternal health and nutrition. Future research in these settings is recommended. This is particularly important in developing countries, where often the pattern is to start childbearing at a young age, have all desired children quickly and then control fertility through permanent contraception, thereby contracting women's fertile years and potentially increasing their exposure to the ill effects of very short IPIs.

Rate of gestational weight gain, pre-pregnancy body mass index and preterm birth subtypes: a retrospective cohort study from Peru

OBJECTIVE

To examine the shape (functional form) of the association between the rate of gestational weight gain, pre-pregnancy body mass index (BMI), and preterm birth and its subtypes.

DESIGN

  Retrospective cohort study.

SETTING

  National reference obstetric centre in Lima, Peru.

POPULATION

  Pregnant women who delivered singleton babies during the period 2006-2009, resident in Lima, and beginning prenatal care at ≤ 12 weeks of gestation (n=8964).

METHODS

  Data were collected from the centre database. The main analyses consisted of logistic regression with fractional polynomial modelling.

MAIN OUTCOME MEASURES

  Preterm birth and its subtypes.

RESULTS

  Preterm birth occurred in 12.2% of women, being mostly idiopathic (85.7%). The rate of gestational weight gain was independently associated with preterm birth, and the shape of this association varied by pre-pregnancy BMI. In women who were underweight, the association was linear (per 0.1 kg/week increase) and protective (OR 0.88; 95% CI 0.82-1.00). In women of normal weight or who were overweight, the association was U-shaped: the odds of delivering preterm increased exponentially with rates <0.10 or >0.66 kg/week, and <0.04 or >0.50 kg/week, respectively. In women who were obese, the association was linear, but non-significant (OR 1.01; 95% CI 0.95-1.06). The association described for preterm birth closely resembled that of idiopathic preterm birth, although the latter was stronger. The rate of gestational weight gain was not associated with indicated preterm birth or preterm prelabour rupture of membranes.

CONCLUSIONS

  In Peruvian pregnant women starting prenatal care at ≤ 12 weeks of gestation, the rate of gestational weight gain is independently associated with preterm birth, mainly because of its association with idiopathic preterm birth, and the shape of both associations varies by pre-pregnancy BMI.

Racial-ethnic differences in pregnancy-related weight

This review examines published literature to answer 2 questions: 1) Are there racial-ethnic differences in excessive or inadequate gestational weight gain (GWG) and postpartum weight retention (PPWR)? and 2) Is there evidence that approaches to promote healthy weight during and after pregnancy should vary by race-ethnicity? We identified a limited number of articles that explicitly looked at racial-ethnic differences in either GWG or PPWR after controlling for relevant covariates. These studies suggest that black and Hispanic women are more likely to gain inadequately based on the Institute of Medicine's pregnancy weight gain guidelines compared to white women. Black women are more likely to retain considerable amounts of weight postpartum compared to both Hispanic and white mothers. Studies were inconclusive as to whether Hispanic women retained more or less weight postpartum, so more research is needed. Interventions to increase GWG were few and those designed to reduce GWG and PPWR showed mixed results. Future studies should address the methodological and conceptual limitations of prior research as well as investigate biological mechanisms and behavioral risk factors to determine the reasons for the racial-ethnic differences in pregnancy-related weight outcomes. Interventions would benefit from a mixed-methods approach that specifically identifies race-relevant barriers to weight management during and after pregnancy. Attention to the greater social context in which pregnancy-related weight exists is also needed.

Determinant factors of insufficient and excessive gestational weight gain and maternal-child adverse outcomes

OBJECTIVE

To estimate the magnitude and determinant factors of insufficient and excessive gestational weight gain (GWG) and its relation with maternal-child adverse outcomes.

METHODS

This was a prospective study with 173 pregnant women and their newborns monitored at a primary health care facility in Rio de Janeiro. Multinomial regression models were employed, having as the outcome the adequacy of GWG (insufficient, adequate, or excessive). Covariables were classified as biological, socioeconomic, reproductive, behavioral, and nutritional.

RESULTS

Forty-one percent of pregnant women had insufficient GWG and 22.0% had excessive GWG. Pregestational overweight was associated with insufficient GWG (odds ratio [OR] 0.19, 95% confidence interval [CI] 0.05-0.78), and pregestational obesity was associated with excessive GWG (OR 4.66, 95% CI 1.34-19.08). Also associated with insufficient GWG were a stature <157 cm (OR 2.25, 95% CI 1.03-4.93) and ages 25-29 y (OR 3.70, 95% CI 1.26-10.84) and >or=30 y (OR 2.88, 95% CI 1.13-7.35) compared with the reference group (18-24 y). Age <12 y at menarche (OR 4.97, 95% CI 1.51-16.30) and being a former smoker (OR 5.18, 95% CI 1.62-16.52) demonstrated an association with excessive GWG compared with non-smokers (reference group). Sixty percent of pregnant women with excessive GWG delivered by cesarean section compared with 39.8% with adequate or insufficient GWG (P < 0.05). Prevalence of macrosomia in the excessive GWG group was 23.5% compared with 4.5% for pregnant women with insufficient GWG (P < 0.001).

CONCLUSION

Different determinant factors related to insufficient and excessive GWG were observed, which can be identified in the beginning of pregnancy, thus predicting unfavorable gestational outcomes. An increased percentage of women presented GWGs outside recommended levels.

Length of prenatal participation in WIC and risk of delivering a small for gestational age infant: Florida, 1996-2004

OBJECTIVE

To assess the association between length of prenatal participation in WIC and a marker of infant morbidity. By focusing on small for gestational age, we consider one of the possible pathways through which prenatal nutrition affects fetal growth.

DESIGN/METHODS

The study sample consists of 369,535 matched mother-infant pairs drawn from all singleton live births in Florida hospitals from 1996 to 2004. All subjects received WIC and Medicaid-funded prenatal services during pregnancy. We controlled for selection bias on observed variables using a generalized propensity scoring approach and performed separate analyses by gestational age category to control for simultaneity bias.

RESULTS

Ten percent increase in the percent of time in WIC was associated with 2.5% decrease (95% CI: 2.1-3.0%) in the risk of a full-term an SGA infant. The risk was also significantly decreased for very preterm and late preterm infants (29-33 and 34-36 weeks gestation) but not for extremely preterm infants (23-28 weeks gestation).

CONCLUSIONS

The observed small negative dose response relationship between percent of pregnancy spent in WIC and fetal growth restriction implies that longer participation in the program confers a small measure of protection against delivering an SGA infant.

Predictors of excessive and inadequate gestational weight gain in Hispanic women

Factors influencing gestational weight gain are incompletely understood, particularly among Hispanic women. We assessed medical, sociodemographic, behavioral, and psychosocial predictors of overall gestational weight gain, as well as gains below, within, or above the range recommended by the Institute of Medicine (IOM) within a prospective study of 770 Hispanic (predominantly Puerto Rican) prenatal care patients at a large tertiary care facility in Western Massachusetts. One third of women gained within the recommended range, 22% gained below, and 45% gained above the range. In multivariate analysis, women in the highest category of BMI (P(trend)<0.001) and parity (P(trend)<0.001) gained on average 9 lbs less than those in the lowest category. Increasing time in residence in the continental United States (P(trend)<0.01) as well as a number of prenatal care visits (P(trend)=0.03) were positively associated with weight gain. Overweight women (odds ratio (OR)=2.2, 95% confidence interval (CI) 1.3, 3.8) and those over age 30 years (OR=2.5, 95% CI 1.2, 5.0) were more likely to gain above the IOM range as compared to normal-weight women and those aged 20-24, respectively. Women with <10 years of residence in the United States were 50% less likely to gain above the IOM range as compared to third-generation women (95% CI 0.3, 0.9). Findings identify determinants of gestational weight gain which can form the basis of targeted interventions in this rapidly growing ethnic group.

Nutrient restriction impairs nephrogenesis in a gender-specific manner in the ovine fetus

Inadequate nutrition compromises fetal development and poses long-term health risks for the offspring, even without decreased birth weight. The present study sought to 1) establish the ontogeny of fetal renal glomerulus number (GN) in sheep and 2) evaluate the effects of 50% global nutrient restriction (NR) during early to midgestation on GN and the renin-angiotensin system in the fetal kidney. GN increased from 78 dG (68,560 +/- 3802) to 135 dG (586,118 +/- 25,792). NR increased combined kidney weight (29 +/- 0.6 g versus 23 +/- 1.1 g), whereas decreased GN relative to right kidney weight approached significance in males (26,000 +/- 5300 versus 39,000 +/- 2800 GN/g) compared with control (C) males and females. NR decreased immunoreactive angiotensin II (Ang II) type 1 receptor (AT1) in the NR kidneys at 78 dG and increased renin at 135 dG. Immunoreactive renin decreased from 78 to 135 dG. Female fetuses had more immunoreactive Ang II type 2 receptor (AT2) than male fetuses at 78 dG and males had more AT1 at 135 dG. The present study demonstrates gender-specific differences in fetal growth and development and in fetal kidney development in pregnancies affected by NR.

Pre-pregnancy and pregnancy-related factors and the risk of excessive or inadequate gestational weight gain

OBJECTIVE

Gestational weight gain consistent with the Institute of Medicine's recommendations is associated with better maternal and infant outcomes. The objective was to quantify the effect of pre-pregnancy factors, pregnancy-related health conditions, and modifiable pregnancy factors on the risks of inadequate and excessive gestational weight gain.

METHOD

A longitudinal cohort of pregnant women (N=1100) who completed questions about diet and weight gain during pregnancy and delivered a singleton, full-term infant.

RESULTS

Gestational weight gain was inadequate for 14% and excessive for 53%. Pre-pregnancy factors contributed 74% to excessive gain, substantially more than pregnancy-related health conditions (15%) and modifiable pregnancy factors (11%). Pre-pregnancy factors, pregnancy-related health conditions, and modifiable pregnancy factors contributed fairly equally to the risk of inadequate gain.

CONCLUSION

Interventions to prevent excessive gestational gain may need to start before pregnancy. Women at risk for inadequate gain would also benefit from interventions directed toward modifiable factors during pregnancy.

Factors that influence special care nursery admissions to a district hospital in South-western Sydney

OBJECTIVES

To explore the socio-demographic factors and maternal characteristics that influence special care nursery (SCN) admission for infants of more than 34 weeks' gestation. Particularly, this paper aims (i) to estimate the incidence of SCN admission by various mothers' socio-demographic factors; and (ii) to investigate the relationship between SCN admission and mothers' socio-demographic and obstetric and gynaecological factors.

METHODS

This was a cohort study of 10,148 pregnant women who accessed the birthing unit within a public district hospital in south-western Sydney in New South Wales, between 1998 and 2001. The main outcome measure was risk factors for SCN admission.

RESULTS

The incidence of SCN admission was 11.7%. Multivariate analysis revealed that the risk factors for SCN admission were diabetes, gestational diabetes, high parity, pregnancy induced hypertension, living in suburbs with low education and occupation index, and no private health insurance status.

CONCLUSIONS

The results from this large population-based study suggest that, apart from clinical/medical factors, admission to a special care nursery at a District Hospital was significantly affected by maternal insurance status and level of education and occupation.

Cigarette Smoking and Low Maternal Weight Gain in Medicaid-Eligible Pregnant Women

OBJECTIVES

Weight gain during pregnancy (termed maternal weight gain) is an important predictor of maternal and infant health. This analysis was conducted to examine if cigarette smoking during pregnancy was associated with low maternal weight gain, as defined by the Institute of Medicine's (IOM) recommendations, independent of caloric intake.

METHODS

The participants were 265 Medicaid-eligible, pregnant women. Data were self-reported. Low maternal weight gain was defined as gaining less than the IOM recommendation for a given prepregnancy body mass index (BMI). Logistic regression was used to determine if smokers had greater odds of low maternal weight gain independent of caloric intake.

RESULTS

Approximately 21% of the participants were self-reported smokers. No difference was observed in mean maternal weight gain between smokers and nonsmokers (14.4 kg vs. 13.9 kg, respectively, p = 0.80). However, a greater proportion of smokers were categorized as having low maternal weight gain compared with nonsmokers (35.7% vs. 31.1%). Unadjusted regression analysis showed that the odds of low maternal weight gain were 1.34 times greater for smokers than nonsmokers (odds ratio [OR] = 1.34, 95% confidence interval [CI] 0.73, 2.67). The OR did not materially change after adjustment for daily caloric intake, age, and length of gestation. In addition, the data suggest that the more cigarettes smoked, the higher the odds of having low maternal weight gain.

CONCLUSIONS

The results suggest that cigarette smoking is associated with low maternal weight gain, as defined by the IOM recommendations, independent of caloric intake.