Barbara Abrams

Pregnancy weight gain: still controversial

During the 20th century, recommendations for maternal weight gain in pregnancy were controversial, ranging from rigid restriction to encouragement of ample gain. In 1990, the Institute of Medicine (IOM) recommended weight-gain ranges with the primary goal of improving infant birth weight. These guidelines were widely adopted but not universally accepted. Critics have argued that the IOMs recommendations are unlikely to improve perinatal outcomes and may actually increase the risk of negative consequences to both infants and mothers. We systematically reviewed studies that examined fetal and maternal outcomes according to the IOMs weight-gain recommendations in women with a normal prepregnancy weight. These studies showed that pregnancy weight gain within the IOMs recommended ranges is associated with the best outcome for both mothers and infants. However, weight gain in most pregnant women is not within the IOMs ranges. All of the studies reviewed were observational and there is a compelling need to conduct experimental studies to examine interventional strategies to improve maternal weight gain with the objective of optimizing health outcomes.

Randomized trial of a behavioral intervention to prevent excessive gestational weight gain: the Fit for Delivery Study

BACKGROUND Excessive weight gain during pregnancy is a major risk factor for postpartum weight retention and future weight gain and obesity in women, but few adequately powered randomized controlled trials have examined the efficacy of a behavioral weight-control intervention during pregnancy. OBJECTIVE This study examined whether a behavioral intervention during pregnancy could decrease the proportion of women who exceeded the 1990 Institute of Medicine (IOM) recommendations for gestational weight gains and increase the proportion of women who returned to pregravid weights by 6 mo postpartum. DESIGN This study was a randomized, assessor-blind, controlled trial. Participants were pregnant (13.5 wk gestation), normal-weight (NW; n = 201) and overweight or obese (OW/OB; n = 200) women whose average age was 28.8 y. Participants were randomly assigned within the 1990 IOM weight category (NW compared with OW/OB) to standard care (n = 200) or to a behavioral intervention to prevent excessive gestational weight gain (n = 201). The intervention included one face-to-face visit; weekly mailed materials that promoted an appropriate weight gain, healthy eating, and exercise; individual graphs of weight gain; and telephone-based feedback. The retention at the 6-mo postpartum assessment was 82%. RESULTS Intent-to-treat analyses showed that the intervention, compared with standard care, decreased the percentage of NW women who exceeded IOM recommendations (40.2% compared with 52.1%; P = 0.003) and increased the percentages of NW and OW/OB women who returned to their pregravid weights or below by 6 mo postpartum (30.7% compared with 18.7%; P = 0.005). CONCLUSION A low-intensity behavioral intervention during pregnancy reduced excessive gestational weight gains in NW women and prevented postpartum weight retention in NW and OW/OB women. This trial was registered at clinicaltrials.gov as NCT01117961.

Maternal weight gain pattern and birth weight

Objectives To determine the relationship between maternal weight gain pattern and birth weight. Methods All nonobese, white women delivered at the University of California, San Francisco, between 1980–1990 were eligible for this study. Our study group included 2994 uncomplicated pregnancies with complete data. All recorded prenatal weight gain measurements were used to estimate maternal trimester weight gain, pattern of gain (based on low versus not-low gain at each trimester), and total gain at delivery. Multiple linear regression analysis was used to assess the relationship between these weight gain measurements and fetal birth weight. Results After adjustment for seven covariates, each kilogram of maternal gain in the first, second, and third trimesters was associated with statistically significant increases in fetal birth weight of 18.0, 32.8, and 17.0 g, respectively. When compared with the pattern of gain that was not low in any trimester, patterns with low gain in the first and second trimesters or in the second and third trimesters were associated with significant decreases in birth weights of 133.0 and 88.5 g, but no important change in birth weight was seen for the group whose gains were low in the first and third trimesters. These findings were not due to differences in total weight gain, which averaged approximately 11 kg in these three pattern groups. Conclusion The results suggest that specific patterns of maternal weight gain, particularly weight gain during the second trimester, are related to fetal birth weight.

Severe obesity, gestational weight gain, and adverse birth outcomes

BACKGROUND The 2009 Institute of Medicine (IOM) Committee to Reevaluate Gestational Weight Gain Guidelines concluded that there were too few data to inform weight-gain guidelines by obesity severity. Therefore, the committee recommended a single range, 5-9 kg at term, for all obese women. OBJECTIVE We explored associations between gestational weight gain and small-for-gestational-age (SGA) births, large-for-gestational-age (LGA) births, spontaneous preterm births (sPTBs), and medically indicated preterm births (iPTBs) among obese women who were stratified by severity of obesity. DESIGN We studied a cohort of singleton, live-born infants without congenital anomalies born to obesity class 1 (prepregnancy body mass index [BMI (in kg/m(2))]: 30-34.9; n = 3254), class 2 (BMI: 35-39.9; n = 1451), and class 3 (BMI: > or =40; n = 845) mothers. We defined the adequacy of gestational weight gain as the ratio of observed weight gain to IOM-recommended gestational weight gain. RESULTS The prevalence of excessive gestational weight gain declined, and weight loss increased, as obesity became more severe. Generally, weight loss was associated with an elevated risk of SGA, iPTB, and sPTB, and a high weight gain tended to increase the risk of LGA and iPTB. Weight gains associated with probabilities of SGA and LGA of < or =10% and a minimal risk of iPTB and sPTB were as follows: 9.1-13.5 kg (obesity class 1), 5.0-9 kg (obesity class 2), 2.2 to <5.0 kg (obesity class 3 white women), and <2.2 kg (obesity class 3 black women). CONCLUSION These data suggest that the range of gestational weight gain to balance risks of SGA, LGA, sPTB, and iPTB may vary by severity of obesity.

The pattern of maternal weight gain in women with good pregnancy outcomes.

OBJECTIVES This study describes the pattern of maternal weight gain in women with good pregnancy outcomes and provides data to fill in the provisional weight-gain charts published by the Institute of Medicine (IOM) in 1990. METHODS We selected 7002 women with good outcomes (defined by factors related to maternal and infant health) from the University of California, San Francisco, Perinatal Database. For each body mass index category, we compared percentiles of weight gain by trimester in women who achieved the IOM recommendations for total gain and those who did not. RESULTS Trimester rates of gain varied by body mass index category and exceeded IOM guidelines in all groups. Forty percent of these women with good outcomes had total gains within the guidelines and provided data to complete the IOM weight-gain charts. CONCLUSIONS Most women in this good-outcome sample would have been suspected of being at increased risk for poor outcome on the basis of their weight gain. This confirms the IOM recommendation that evaluation of the underlying causes of excessively high or low weight gain during pregnancy is necessary before appropriate interventions can be applied.

Association of maternal gestational weight gain with short- and long-term maternal and child health outcomes.

OBJECTIVE The purpose of this study was to investigate the associations between gestational weight gain (GWG) and small- and large-for-gestational-age (SGA, LGA), cesarean delivery, child overweight, and maternal postpartum weight retention in a diverse sample of women in the Unites States. STUDY DESIGN We estimated associations between GWG (continuous and within categories defined by the Institute of Medicine), maternal prepregnancy body mass index, and each outcome in 4496 births in the National Longitudinal Survey of Youth 1979, which was a prospective cohort. RESULTS GWG (kilograms) was associated with decreased risk of SGA and increased risk of LGA, cesarean delivery, postpartum weight retention, and child overweight independent of maternal demographic and pregnancy characteristics. Gain above the Institute of Medicine guidelines was associated with decreased risk of SGA and increased risk of all other outcomes. CONCLUSION Excessive gain may have long-term consequences for maternal and child body size, but the benefits of lower gain must be balanced against risk of SGA.

Factors associated with the pattern of maternal weight gain during pregnancy

Objective To examine the pattern of maternal weight gain using maternal characteristics and pregnancy outcome. Methods We used maternal weight data measured prospectively from all deliveries between 1980–1990 at the University of California, San Francisco. Piecewise linear regression was used to estimate the rate of maternal weight gain in each trimester. Bivariate techniques were used to examine associations between maternal weight gain per trimester and maternal characteristics and pregnancy outcomes. We also used multiple regression analysis to examine the relationship between maternal characteristics and trimester weight gain. Results Weight data for at least one trimester were available for 10,418 women. The average rate of weight gain (kg/week) was lowest during the first trimester (0.169 ± 0.268, n = 7587), peaked during the second trimester (0.563 ± 0.236, n = 8000), and slowed slightly in the third trimester (0.518 ± 0.234, n = 10,052). Maternal height, hypertension, cesarean delivery, and fetal size correlated positively with the rate of gain in each trimester, but pre-pregnancy body size, age, parity, smoking status, race-ethnicity, and diabetes were associated differently with gain, depending on which trimester was examined. The most important maternal predictors of weight gain per trimester were age and Asian race-ethnicity in the first trimester; pre-pregnancy body mass, parity, and height in the second; and hypertension, age, and parity in the third. Conclusion Maternal weight gain per trimester is associated with a number of maternal characteristics and pregnancy outcomes, and these relationships vary according to which trimester is being examined.

Neighborhood Socioeconomic Status, Maternal Race and Preterm Delivery: A Case-Control Study

PURPOSE To explore associations between neighborhood socioeconomic context and preterm delivery, independent of maternal and family socioeconomic status, in African-American and white women. METHODS A case-control study of African-American (n = 417) and white (n = 1244) women delivering infants at the University of California, San Franciscos Moffitt Hospital, between 1980 and 1990. RESULTS Neighborhood socioeconomic contexts were associated with preterm delivery but associations were non-linear and varied with race/ethnicity. For African-American women, living in a neighborhood with either high or low median household income was associated with an increased risk of spontaneous preterm delivery, as was living in a neighborhood with large increases or decreases in the proportion of African-American residents during the study decade. Residence in neighborhoods with high and low rates of male unemployment was associated with a decreased risk of preterm delivery. Among white women only large positive and negative changes in neighborhood male unemployment were associated with risk of preterm delivery. CONCLUSIONS Neighborhood factors and changes in neighborhoods over time are related to preterm delivery, although the mechanisms linking local environments to maternal risk remain to be specified.

Recommendations for weight gain during pregnancy in the context of the obesity epidemic

The Institute of Medicine and the National Research Council have issued new guidelines for gestational weight gain as well as recommendations for action and research that call for “a radical change in the care provided to women of childbearing age.” For the first time, these guidelines consider the outcomes of both mother and child during and after delivery and the trade-offs between them. The recommendations call for women to begin pregnancy at a healthy weight and to gain within the guidelines, a goal not previously achieved. They also call for individualized preconceptional, prenatal, and postpartum care to help women attain a healthy weight, gain within the guidelines, and return to a healthy weight. Scientific evidence was inadequate to provide specific guidelines by obesity class or to support a public health recommendation to reduce the guidelines below 5-9 kg (11-20 lb) for obese women.

Preventing excessive weight gain in pregnancy: how do prenatal care providers approach counseling?

BACKGROUND Excessive weight gain during pregnancy is becoming more common and is associated with many adverse maternal and infant outcomes. There is a paucity of data on how weight gain counseling is actually provided in prenatal care settings. Our objective was to study prenatal care providers and their knowledge, attitudes, and practices regarding prevention of excessive weight gain during pregnancy and, secondarily, their approach to nutrition and physical activity counseling during pregnancy. METHODS We conducted seven focus groups of general obstetrician/gynecologists, midwives, and nurse practitioners. We analyzed data using qualitative methods. RESULTS Providers agreed to participate because they were unsure of the effectiveness of their counseling efforts and wanted to learn new techniques for counseling patients about weight gain, nutrition, and physical activity. We identified several barriers to weight gain counseling, including insufficient training, concern about the sensitivity of the topic, and the perception that counseling is ineffective. Providers all agreed that weight gain was an important topic with short-term and long-term health consequences, but they described widely disparate counseling styles and approaches. CONCLUSIONS Prenatal care providers are deeply concerned about excessive weight gain and its sequelae in their patients but encounter barriers to effective counseling. Providers want new tools to help them address weight gain counseling during pregnancy.