Recommendations
The Institute of Medicine (IOM) recommendations for gestational weight gain are based on body mass index (BMI) of women prior to pregnancy. However, early first trimester BMI appears to be a valid proxy for pre-conception BMI. BMI is split up into four categories: underweight (<18.5 kg/m^2), normal weight (18.5-24.9 kg/m^2), overweight (25-29.9 kg/m^2), and obese (≥30.0 kg/m^2). The IOM has recommended the ranges of weight gain to be 12.5–18 kg, 11.5–16 kg, 7-11.5 kg, and 5–9 kg respectively. That is, the smaller the BMI pre pregnancy, the more weight a woman is expected to gain during her pregnancy.Contributing factors
Excessive GWG (eGWG) has been shown to adversely affect maternal and baby health postpartum. Only a little over a quarter of women have adequate GWG, meaning that their weight gain during pregnancy falls within the IOM recommended range. A little less than a quarter of women have inadequate GWG. However, excessive GWG is the most prevalent occurring in around half of pregnant women.Pre-pregnancy BMI
Having a higher BMI pre-pregnancy may leave you at a greater risk for excessive gestational weight gain and ultimately for cardio-metabolic diseases prenatally and postpartum.Food access
Expectations
Overweight and obese women are significantly more likely to expect excessive gestational weight gain compared with normal-weight women, and women who report expecting to gain excessively are three times more likely to actually gain excessively than those who expect to gain within the guidelines.Income
Regardless of a relation to food security, having a low income might also predispose women to excess gestational weight gain, yet the reasoning is unclear. One possibility is related to stress. Financial stress has been shown to be positively correlated with levels of CRP postpartum, a stress hormone associated with weight gain most likely because people eat increasingly unhealthy when stressed. Women with a higher monthly budget for food may have a healthier gestational weight gain, while those with less money allocated for food may be more likely to experience excessive gestational weight gain. However, the opposite may also be true: wealthier women may be more likely to suffer from excess gestational weight gain. Women in wealthy communities have been reported to have higher postpartum weight retention than those in more poverty, and since women who have excessive gestational weight gain are more likely to retain weight postpartum women in less poverty might be more likely to have excess gestational weight gain. This suggests that a greater household income does not necessarily provide protection against excess gestational weight gain.Race/ethnicity
Race/ethnicity is an important variable to take into account when discussing gestational weight gain because women of racial/ethnic minorities demonstrate disproportionately higher obesity levels than non-Hispanic white women. The IOM guidelines were created from data mostly consisting of white women, and thus may not be an appropriate measure for women of other races/ethnicities. African American women in general may have higher postpartum cardio-metabolic risk and more excess gestational weight gain than Latina women, who in turn have more than white women. However, this is not always the case. One study reported that although African American women are more likely to be overweight or obese pre-pregnancy, they were less likely to have excessive weight gain than white women in one study.Poverty
Even though in many areas in the United States, there has been a decline in inequality on the basis of race/ethnicity, there still exists disproportionate social stratification. Racial/ethnic minorities, such as blacks and Latinos, are more likely to be found in neighborhoods high in poverty. African American women in poverty have been seen to have significantly higher postpartum cardio-metabolic risk than wealthier African American women, which could be partially related to these impoverished women having excess gestational weight gain. White women in poverty, on the other hand, had excess gestational weight gain and higher postpartum cardio-metabolic risk than the white women with higher incomes. This was also true for Latina women in poverty compared to those wealthier. The information regarding how race/ethnicity affects experience of excess gestational weight gain can be related to poverty levels, and the data available is limited and variable.References
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