Obesity in Pregnancy

Obesity in Pregnancy

Tania Roman

Patrick S. Ramsey


Pregnancy is a time of significant change in a woman’s life. The pregnant body undergoes a myriad of physiological changes not seen simultaneously in any other medical condition. As more women delay childbearing and new public health concerns gain strength, the care for the pregnant woman becomes more complex and challenging. One of those compelling public health issues is the rising obesity epidemic taking place around the world, specifically in developed countries. It is for this reason that physicians should be aware of the potential issues surrounding women with obesity in order to address them preconceptually and throughout the pregnancy and puerperium. This is a collaborative task requiring a multidisciplinary approach in the realm of obstetrics, public health, and general medicine.


Over the past 3 decades, obesity rates in the United States have increased. Based on data collected over a 1-year period, from 2015 to 2016, more than one-third of adults (39.8%) were obese, and almost one-fifth of all youths (18.5% aged 5-18 years) were obese. A breakdown by gender shows that 41.1% of women aged 20 years and older and 36.5% of women aged between 20 and 39 years were obese (Figure 32.1).2 These staggering numbers do not seem to be on the decline, as these rates have been steadily increasing over the last 10 years.

The most recent data have also shown differences in obesity prevalence by race and ethnicity. Non-Hispanic black (54.8%) and Hispanic (50.6%) women have the highest rates of obesity. This was followed by non-Hispanic white (38.0%) and non-Hispanic Asian (14.8%) women. These differences reflect the disparities in maternal and neonatal health seen in the United States (Figure 32.2).2


The obesity epidemic affecting pregnant women has a vast array of clinical implications. Pregnant women with obesity have higher rates of severe maternal morbidity (SMM), defined as “unexpected outcomes of labor and delivery that result in significant short- or long-term consequences to a woman’s health.”3 This includes postpartum hemorrhage requiring transfusion; thromboembolic events; and cardiovascular, respiratory, and hematological complications. The excess adipose tissue serves as an active endocrine organ that activates metabolic and inflammatory pathways leading to many pathological processes.4,5 On a molecular level, extracellular vesicles in adipose tissue have been shown to play a role in glucose and lipid metabolism, leading to insulin resistance and metabolic syndrome.6 Given that the amount of excess weight is linearly associated to obstetrical and fetal complications further supports the causative role of obesity in the pathogenesis of these disease processes.7

Clinical Presentation


Maternal Considerations

Recent studies have shown that prepregnancy weight (eg, maternal BMI at conception) is a stronger predictor of adverse maternal and infant outcomes than weight gain during pregnancy. A 2017 meta-analysis of 25 pooled cohort studies of 196,670 participants found that the odds ratio (OR) for any maternal or fetal adverse outcome per one standard deviation (1-SD) increase in maternal prepregnancy BMI was 1.28 (95% confidence interval [CI] 1.27-1.29) compared to 1.04 (95% CI 1.03-1.05)
per 1-SD increase in gestational weight gain (P < .001 for comparison).8 These findings emphasized the importance of preconceptual counseling to reinforce and educate women on weight loss prior to conception. However, many women may have limited access to health care or may only seek care during pregnancy or when seeking emergency services. For this reason, a majority of education and counseling regarding obesity and pregnancy will have to occur during prenatal care.

Given that earlier studies have shown an association with excess gestational weight gain and adverse maternal neonatal outcomes, the National Academy of Medicine (formerly the Institute of Medicine) provided guidelines regarding gestational weight gain (Table 32.1). Under these recommendations, women with obesity should gain in total 11 to 20 lbs during pregnancy. This is in sharp contrast with women in the normal range (BMI 18.5-24.9 kg/m2) who can gain 25 to 35 lbs during their pregnancy. Of note, the guidelines also addressed women with obesity who had multiple fetuses and recommended a weight gain of 25 to 42 lbs.9

Jun 19, 2022 | Posted by in OBSTETRICS | Comments Off on Obesity in Pregnancy
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