Medical Research: What is the background for this study?
Dr. Johnson: Achieving adequate gestational weight gain (GWG) is important for optimal health of the infant and mother. Women who gain below or above Institute of Medicine (IOM) recommendations are more likely to experience maternal complications and negative infant birth outcomes. Realizing the importance of gestational weight gain to maternal and infant health, the IOM established recommendations for gestational weight gain based on a woman’s prepregnancy body mass index (BMI) in 1990 and updated them in 2009. Trends in GWG are particularly of interest since prepregnancy BMI has increased over time in the U.S and little data was available on how gestational weight gain has changed over time.
Medical Research: What are the main findings?
Dr. Johnson: Our findings show that from 2000-2009, the majority of women did not gain weight within IOM GWG recommendations and that women were more likely to gain outside recommendations in more recent years. In fact, from 2000–2009, there was a gradual decrease (1.0 percentage point every 2 years) in women gaining within IOM gestational weight gain recommendations and a gradual increase (0.8 percentage points every 2 years) in women gaining above IOM recommendations while the percentage of women gaining weight below IOM recommendations remained relatively constant. Although there were slight differences in mean gestational weight gain by BMI group, gestational weight gain was about 31 pounds on average. The decreasing percentage of women gaining within IOM recommendations during our study period may be influenced by increases in prepregnancy BMI during the same time period because women in higher BMI groups are recommended to gain less weight during pregnancy compared to women in lower BMI groups. Thus, even with no change in gestational weight gain over time, an increase in the proportion of women who are obese could result in a decrease in the proportion of women gaining within gestational weight gain recommendations.
Medical Research: What should clinicians and patients take away from your report?
Dr. Johnson: Our study is the first to report gestational weight gain trends by obesity class and to examine trends adjusted for demographic and health characteristics. Our results demonstrate the need for more efforts to encourage and support women to enter pregnancy at a healthy weight and gain within gestational weight gain recommendations. Although surveys of obstetrician/gynecologists’ practices suggests that the majority counsel pregnant women on gestational weight gain and nonpregnant women on weight control, these efforts may not be sufficient. To help women achieve appropriate gestational weight gain, the IOM has developed an evidence-based toolkit to help clinicians and pregnant women track and meet weight gain goals (www.iom.edu/whattogaintoolkit).
Enhanced cultural and social sensitivity training may be needed to improve communication on weight gain during pregnancy. Increased public awareness of the consequences of excess weight gain during pregnancy may also improve the effectiveness of gestational weight gain counseling. Current 2009 IOM gestational weight gain recommendations for total weight gain during pregnancy include: underweight women (<18.5 kg/m²) 28-40lbs, normal weight women (18.5-24.9 kg/m²) 25-35lbs, overweight (25.0-29.9 kg/m²) women 15-25lbs and obese women (≥30.0 kg/m²) 11-20lbs.
Healthy lifestyle recommendations for pregnant women which may help with gestational weight gain within recommendation include:
o Pregnancy does not equate to eating for two. The first trimester does not require any extra calories. In general for all women, to meet the metabolic needs of pregnancy, women need an additional 340 calories per day during the second trimester and 450 calories per day during the third trimester.
o Women should be encouraged to eat a balanced diet with an increase in fruits and vegetables and to limit intake of added sugars and solid fats in foods like soft drinks, desserts, fried foods, cheese, whole milk, and fatty meats.
o Women should get at least 150 minutes per week of moderate-intensity aerobic activity during and after pregnancy.
o Healthy women who already engage in vigorous-intensity activity, such as running, can continue doing so during and after pregnancy provided they stay healthy and discuss with their health care professionals how and when activity should be adjusted over time.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Johnson: Results from this analysis highlight the need for continued clinical and public health efforts toward developing and scaling up effective strategies to ensure women enter pregnancy at a healthy weight and achieve gestational weight gain within recommendations. Key components of diet-focused interventions have included education on the consequences of the behavior, self-monitoring of behavior, and contingency rewards for successful behavior. There is also evidence that interventions may be more effective if community based strategies are incorporated which encourage change in social and behavioral attitudes and norms towards diet and exercise in pregnancy.
Jonetta L. Johnson, PhD, MPH, Epidemiologist, & Division of Reproductive Health, CDC. (2015). Many Women Exceeding Gestational Weight Gain Recommendations MedicalResearch.com