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Obesity is a growing epidemic in the United States and throughout the developed world. According to the Centers for Disease Control and Prevention (CDC), only 13% of Americans were considered obese in 1962. This number significantly increased to 35% by 2013. Today, every state in the country has at least a 20% prevalence of obesity, with two states now over 35%.1 This trend extends to parturients, with over half of all pregnant patients being overweight and obese, and 8% reaching extreme obesity.2


The classification of obesity has been standardized with the use of the body mass index (BMI, kg/m2), with a value of 30 or greater being considered obese. While the World Health Organization (WHO) has subdivided obesity into three classes (Table 27-1), the Institute of Medicine guidelines regarding gestational weight gain do not discriminate based on this classification (Table 27-2).3,4

Table 27-1.Body Mass Index (BMI) Classification System
Table 27-2.Institute of Medicine Recommendations for Total Weight Gain During Pregnancy, Based on Prepregnancy Body Mass Index (BMI)


Obesity results from an imbalance of caloric intake and physical activity. While it is recommended to perform at least 30 minutes of exercise daily during pregnancy, most parturients do not meet this goal.5,6

Obesity is an independent risk factor for maternal and neonatal morbidity.7 Therefore, preconception counseling should occur for all obese women of childbearing age to 1) educate these patients about their risk and 2) enable weight reduction strategies to occur prior to pregnancy. When pregnancy occurs, patients should be educated about the effects of obesity on the course of pregnancy, labor and delivery.2 Nutritional consultation and exercise goals should be established early and evaluated throughout pregnancy. Despite adequate consultation, only 19% of obese parturients believe their weight affects pregnancy risk.


Maternal obesity, has been implicated as a risk factor for structural defects in the fetus, including congenital heart defects, facial clefting, hydrocephalus, limb reduction and most commonly neural tube defects.9

These congenital anomalies may be poorly visualized ...

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