Implementation of the New Institute of Medicine Gestational Weight Gain Guidelines

Anna Maria Siega-Riz, PhD, RD; Andrea Deierlein, PhD, MPH; Alison Stuebe, MD, MSc

Disclosures

J Midwifery Womens Health. 2010;55(6):512-519. 

In This Article

The Role of Health Care Providers in the Implementation of the New IOM Gestational Weight Gain Guidelines

In today's obesogenic environment, the majority of women are anticipated to have difficulty limiting weight gain to the upper limit of the new IOM guidelines. Data from the past 10 years illustrate that most women gain in excess of the recommendations.[3–5] Interventions to improve dietary intake and physical activity are necessary to achieve the targeted weight gains. Health care providers of pregnant women play a primary and influential role in such interventions because they have the ability to provide holistic and individualized care. This guidance should begin before conception and last through the postpartum period.

This section discusses practical guidelines for implementing the new IOM weight gain guidelines before, during, and after pregnancy. Health or nutrition advice that is unrelated to gestational weight gain is not addressed. For such information, readers are referred to the American Dietetic Association (ADA) and American Society for Nutrition position papers on obesity, reproduction, and pregnancy outcomes[15] and nutrition and lifestyle for a healthy pregnancy outcomes.[16] In addition, specific nutritional and physical activity advice for the implementation of the new weight gain guidelines is provided in a companion article in this issue by Widen and Siega-Riz.[17]

Preconception

In the preconception period, health care providers have an ideal opportunity to counsel women about healthy lifestyle behaviors and provide guidance regarding appropriate weight so that they enter pregnancy in the optimal state. Assessment and surveillance of the woman's prepregnancy BMI status, nutritional and physical activity behaviors, and mental health are of primary interest. Prepregnancy BMI status has important implications for both maternal and infant health outcomes during pregnancy, independent of gestational weight gain. Women who are obese before pregnancy are at greater risk of complications such as gestational diabetes, preeclampsia, and cesarean delivery, as well as infant health complications, such as macrosomia and large for gestational age.[18] Women who are underweight before pregnancy are also at greater risk of complications, including low birth weight and small for gestational age.[18] Health care providers need to emphasize the importance of achieving normal BMI status before pregnancy and educate women about the risks of having a BMI outside of the normal range.

Both rapid, substantial weight loss and obesity may decrease a woman's ability to conceive. Women who are overweight or obese may be referred to dieticians or other medical consultation services to assist with weight loss before pregnancy. The ADA position paper on weight management,[19] which has been endorsed by the American College of Sports Medicine, is an excellent guide for providers to follow, as is their evidence analysis library.[20] Assessments of anthropometrics, medical factors, psychological factors, and nutritional habits are helpful in identifying target areas for weight management. Women who are underweight may also be referred to dieticians to improve nutritional status. Women who indicate body image issues or disordered eating, such as restrained eating, binging, and food avoidance, should be referred to a dietician or mental health care provider as necessary. If untreated, disordered eating behaviors may influence a woman's current nutritional status and may continue to persist throughout pregnancy. Sample questionnaires and checklists are provided in Nutrition During Pregnancy and Lactation: An Implementation Guide.[21]

Health care providers may also choose to familiarize women with the IOM gestational weight gain guidelines at this time. It is important that women are aware of prepregnancy-specific weight gain recommendations and that they understand that appropriate weight gain during pregnancy is an integral part of achieving healthy outcomes for themselves and their infants.

Early Pregnancy: First Trimester

Once pregnancy is confirmed, health care providers should incorporate monitoring of gestational weight gain as part of the prenatal care regimen. Gestational weight gain charts (Figure 1, Figure 2) should be shown to women as an illustrative example of the expected pattern of weight gain during pregnancy: weight gain is usually minimal during the first trimester and close to linear through the second and third trimesters until birth. These charts were developed by the IOM committee to be used as a basis for this discussion with the woman, and they can also be included in her medical record. The range around the target line in the second and third trimesters reflects the final width of the target range. The charts are meant to be used as a part of a comprehensive assessment of a woman's weight gain during pregnancy, looking beyond the gain from one visit to the next and toward the overall pattern of weight gain. This approach is needed because the pattern of gestational weight gain, like total gestational weight gain, is highly variable, even among women with good pregnancy outcomes.[22]

Figure 1.

Weight gain charts for underweight and normal weight BMI categories. The median (solid lines) and range (dotted lines) of recommended weight gain (lb) for pregnant women within underweight (BMI <18.5) and normal weight (BMI 18.5–24.9) categories.

Figure 2.

Weight gain charts for overweight and obese BMI categories. The median (solid lines) and range (dotted lines) of recommended weight gain (lb) for pregnant women within overweight (BMI 25-29.9) and normal weight (BMI ≥30) categories.

At the first prenatal visit, providers should calculate prepregnancy BMI using previously measured weights and heights or self-reported prepregnancy weight to establish the appropriate weight gain range. Rather than focus on a particular number, this weight gain range serves as the woman's weight gain goal (Figure 1, Figure 2). The current gestational weight gain is determined by subtracting the prepregnancy weight from the first prenatal visit measured weight to create a starting point for monitoring gestational weight gain. This starting weight can then be plotted on the IOM weight gain chart and shared with the woman so that she can become aware of and involved in her progress toward her weight gain goal. Women who have gained a substantial amount of weight by the first prenatal visit should be counseled about their current activity and diet behaviors (discussed below) to troubleshoot any issues related to gestational weight gain. These women should be encouraged to aim for a steady rate of weight gain according to their recommended goal range, using the IOM weight gain chart as a visual example. Providers should also remind women that weight gain can fluctuate throughout pregnancy. Women should not try to lose any weight during pregnancy, and they should continue to follow a healthy diet and physical activity routine.

At the initial visit, health care providers should assess the woman's attitudes toward weight gain, physical activity, and nutrition during pregnancy and provide individualized advice based on this assessment. Asking open-ended questions, such as "What have you heard about weight gain during pregnancy?" allows the provider to target education to the woman's needs and concerns. Providers should encourage women to continue exercising and remind them that pregnancy requires modest increases in calories (350–450 calories on average), but great increases in vitamins and minerals, starting in the second trimester. Simple dietary assessments, such as 24-hour diet recalls and food records and checklists, can be used by the health care provider to monitor diet and nutrient intakes throughout pregnancy. Detailed guidelines and recommendations for appropriate nutrition and physical activity to help guide adequate gestational weight gain can be found in the companion article in this issue.[17] Women expressing negative attitudes toward weight gain or signs of disordered eating should be referred to a dietician or mental health care provider. These women need to be counseled that regardless of prepregnancy BMI, pregnancy is not a time for dieting or attempting weight loss. Women with low incomes and food insecurity issues should be referred to the Women, Infants, and Children (WIC) program to ensure that they receive benefits and services as quickly as possible.

Women should also be screened for depression. In a metaanalysis by Gaynes et al.,[23] it was estimated that one in seven women develop depression during pregnancy or after giving birth. Data for US women 18 to 29 years of age illustrate striking increases in the prevalence of major depression from 1991 and 1992 to 2001 and 2002, with more than 10% of women being depressed. Similar trends were observed for women 30 to 44 years of age, but the prevalence rates were lower.[24] Depression during pregnancy is associated with both low[25,26] and high[27] gestational weight gains. Intervention and treatment for symptoms of depression and other psychological factors, such as stress and social support, may be required during pregnancy to achieve optimal gestational weight gains.

The health care provider may also initiate conversations regarding infant feeding plans and the woman's intention to breastfeed, especially among women who are overweight or obese. Studies show that these women are less likely to initiate and have a shorter duration of breastfeeding compared to women who are normal weight and underweight.[28–31] Breastfeeding may play an important role in weight loss during the postpartum period if healthy diet and physical activity habits are implemented.

Later Pregnancy: Second and Third Trimesters

Throughout the second and third trimesters, health care providers should continue to track the weekly rates and total gestational weight gains using the IOM chart. This chart is intended to aid both the health care provider and woman in tracking gestational weight gains and assessing the overall pattern of weight gain. The IOM-recommended mean weekly weight gains are 1 lb for women who are underweight or normal weight, 0.6 lb for women who are overweight, and 0.5 lb for women who are obese (Table 1). Providers should encourage women to participate in tracking, monitoring, and interpreting their weight gains and should provide positive feedback about meeting their weight gain goals. Women with inadequate or excessive patterns of weight gain should be identified, and possible reasons for these patterns should be investigated and addressed. Potential considerations for slow and rapid gestational weight gain are presented in Table 3, Table 4, respectively.

Once the reason for inadequate or excessive weight gain is identified, the provider and woman can develop a management plan. The health care provider should seek to determine the woman's perception of the seriousness of her inappropriate weight gain and the likelihood that it will negatively affect her or her baby's health. If the woman does not believe that it is a serious problem or that this problem applies to her, then personalized information should be offered to help her see it as a problem for her. For example, a woman with inadequate weight gain may prefer a smaller baby because she wants an easier birth, but smaller babies are more likely to experience morbidity during the first year of life. The woman can then be involved in identifying her current behaviors that support or impede her ability to achieve the targeted weight gain objective and assess any barriers to changing her behaviors. It is optimal to identify more than one behavior (such as increasing or decreasing physical activity, increasing or decreasing energy intakes, and taking specific actions to decrease stress) so the woman has choices, and to begin with small changes that she will be able to make and maintain. The companion article[17] discusses actions to reduce barriers, including the provision of support groups or a buddy program, food assistance programs, and informational materials, as well as the importance of positive feedback.

In any case, the objective should be to aim for the target rate of weight gain on the IOM chart. For women who have gained too much weight at the start of pregnancy, this may mean exceeding the original recommended range. The goal should be to get women on the right track while ensuring that fetal growth is as expected and the woman continues to exercise; consume nutrient-dense foods, such as fruits, vegetables, whole grains, and lean meats; and look for ways to cut back on foods high in calories, fat, and sugar. For the woman who is gaining inadequately, she may need encouragement to eat more healthy foods while balancing her physical activity routines. One exception is inadequate weight gain (including no change in weight or weight loss) among women who are obese, which has been shown to be safe and result in optimal birth outcomes;[34,35] however, the implications of weight loss for the long-term health status of the child are unknown. Women who are obese and have such weight change patterns may not need to be encouraged to gain weight as long as they are closely monitored for proper nutrition and fetal growth.

Postpartum

After birth, services and counseling should be provided to help women return to their prepregnancy weight within the first year and, ideally, to achieve a normal BMI before the next pregnancy. Health care providers should monitor women for retention of gestational weight gain during the postpartum period, because such weight retention both increases the risk of complications in the subsequent pregnancy and is a major predictor of later-life obesity. Using data from the Pregnancy Nutrition Surveillance System (PNSS; conducted between 2004 and 2006), at 6 months' postpartum or later, the mean postpartum weight retention was 11.8 lb, with approximately 50% of the women retaining more than 10 lb and 25% retaining more than 20 lb. Postpartum weight retention was especially prevalent among women who gained in excess of the recommended guidelines, with the mean weight retention ranging 15 to 20 lb across the prepregnancy BMI categories, and greater than 40% of women retaining more than 20 lb.[10]

Health care providers should continue to endorse appropriate nutrition and physical activity behaviors, as well as breastfeeding, to promote weight loss. It is important to realize that a new mother needs support from her partner, family, and friends to adopt these behaviors. Women who are overweight or obese are less likely to initiate breastfeeding and more likely to breastfeed for shorter durations than their normal weight counterparts.[36,37] Techniques to support lactating mothers, especially those who are obese, are described by Jevitt et al.[36] In addition, certain factors related to the pregnancy, such as hospitalization of the child, depression, and number hours of sleep have been related to retained gestational weight gain.[38–40] It is important to assess these factors and provide appropriate counseling to achieve the necessary postpartum weight loss. Other strategies can be adopted from the ADA position paper on weight management.[19] It may take several months with a total energy reduction of 500 to 1000 kcals of daily intake and a weight loss of 1 lb to 2 lb per month to achieve prepregnancy weight. Weight loss is usually fast over the first month postpartum but gradual thereafter, and may vary by prepregnancy BMI status. Gunderson et al.[41] found that mean postpartum weight losses within the first 6 weeks postpartum were similar across maternal prepregnancy BMI categories, ranging from 6.3 to 6.6 kg. However, mean weight losses between 6 weeks and a median of 2 years postpartum were approximately 4 kg for underweight and normal weight women but 3 kg and 0.3 kg for overweight and obese women, respectively.

Lactation accounts for approximately 500 to 700 kcals per day in energy expenditure,[42,43] depending on the duration of lactation and maternal metabolic factors, and may aid in postpartum weight loss. In a study by Baker et al.,[44] the researchers used estimates from multiple linear regression to predict the contribution of exclusive breastfeeding for 6 months to eliminating postpartum weight retention. Among women with gestational weight gains of 12 kg or less, exclusive breastfeeding was predicted to result in weight loss that eliminated postpartum weight retention by 6 months postpartum, regardless of prepregnancy BMI status. For women who gained more than 12 kg, exclusive breastfeeding was predicted to reduce, but did not eliminate, postpartum weight retention at 6 months postpartum. Women who are breastfeeding should consume adequate amounts of fluids and calories to maintain milk production and provide nutrients for maternal and infant health. However, they should be reminded that significantly increased energy intakes are not necessary; weight loss will occur only if an energy deficit is created from the energy expenditure needed for milk production. In one study of women who were breastfeeding and overweight, exercise of at least 45 minutes per day for 4 days per week and a 500-kcal decrease in daily energy intake were necessary to promote weight loss of 0.5 kg per week.[45] This suggests that substantial energy restriction is required among women who are breastfeeding and overweight or obese to achieve weight loss in the postpartum period. Women attempting energy restriction need to be monitored for safety and adequate vitamin and micronutrient intakes, specifically calcium and vitamins C, D, and E.[46] Infant growth should also be monitored; however, several studies have shown that exercise and diet have no effect on breast milk composition or infant outcomes.[45,47–49]

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