Obesity during pregnancy causes many risks for both the mother and the baby. The American Congress of Obstetricians and Gynecology classifies obesity as having a body mass index (BMI) of 30 or greater. The higher the BMI, the greater the risk.

The mother may be at risk for the following complications if she is obese during pregnancy:

• Gestational diabetes: diabetes first diagnosed during pregnancy which may increase the risk of having diabetes after pregnancy. Gestational diabetes also increases the risk of having a cesarean delivery.
• Preeclampsia: a high blood pressure disorder that can occur during or after pregnancy. Preeclampsia may cause the kidneys and liver to fail as well as lead to seizures, a condition called eclampsia.
• Problems with diagnostic testing: obese mothers may encounter inaccurate diagnostic screenings such as ultrasound testing due to their size. Some common concerns are not being able to see the baby’s heart or spine development fully, and not being able to see the mother’s ovaries completely to determine if there are any problems.
• Sleep apnea: a condition in which a person stops breathing for short periods while sleeping. This condition is often associated with obesity and may increase of the risk of high blood pressure, preeclampsia, and heart and lung problems.
• High risk pregnancy: once a mother is determined to be obese and pregnant, she will likely be diagnosed as a high-risk pregnancy and need follow-up with a Maternal Fetal Medicine specialist to monitor the pregnancy.

Obesity during pregnancy not only causes complications for the mother, but the baby may be affected as well. The following complications may occur for the baby:

• Miscarriage: obese women have an increased risk of miscarriage than women of normal weight.
• Birth defects: babies born from obese women have an increased risk of having heart or neural tube defects.
• Preterm birth: complications from the mother’s obesity, such as preeclampsia, may result in the baby needing to be born early. Babies born before 39 weeks may suffer from short-term or long-term complications from being born before they are fully developed.
• Macrosomia: a condition in which the baby is born larger than normal, which can increase the chance of the mother needing a cesarean delivery, or the baby becoming obese later in life.
• Stillbirth: the more obese the mother, the higher the risk of the baby being delivered stillborn.

Despite the risks, obese pregnant women can have a healthy pregnancy with proper weight management and prenatal care. However, losing weight before becoming pregnant can significantly decrease the risks of complications for both the mother and the baby, and result in a much healthier pregnancy.