Obesity in Pregnancy

It’s important to know the risks to both mom and baby with obesity in pregnancy.

It’s important to know the risks to both mom and baby with obesity in pregnancy.

Roughly one-third of women between the ages of 20 and 39 will meet the criteria for obesity. (Obesity is defined by a “body mass index” over 30kg/m2. Body mass index, or BMI, is calculated based on your height and weight).

Maternal obesity can complicate pregnancy by affecting the fetus and the patient herself.

Outcomes affecting the fetus:

  • It isn’t clear why, but there is an increased risk of fetal malformations when the mother is obese. Although several fetal abnormalities are more common when a patient is obese, the risk of neural tube defects (such as spina bifida) are doubled in obese patients.
  • Maternal obesity increases the incidence of fetal macrosomia (large babies) and shoulder dystocia. Shoulder dystocia is the term used to describe difficulty in the delivery of the fetal shoulders – which in rare cases may result in permanent neurologic injury.
  • There appears to be an increase in the incidence of ‘Indicated’ preterm deliveries. ‘Indicated’ preterm deliveries are deliveries that are performed because the physician feels that it is in the best interest of either the mother or fetus, or both.
  • There is an 80 percent increase in the incidence of stillbirth for women who are obese.

Outcomes affecting mother

  • Women who are obese are three times as likely to get gestational diabetes as lean women.
  • The risk for preeclampsia appears to double for each 5-7kg/m2 increase in  BMI over 30 kg/m2
  • There is an increase in the risk for cesarean section for obese patients, and unfortunately these cesarean deliveries carry a greater risk of significant hemorrhage, blood clots, or infection than those performed in non-obese patients.
  • There is a greater risk for epidural failure for obese patients – in one report as high as 42% – probably because it is more difficult to get the epidural catheter in the correct location.
  • Studies suggest an association between obesity and failure to begin breastfeeding.


Obviously, the best advice I can offer is to attempt weight loss before pregnancy. A healthy diet and plenty of exercise can make it easier to conceive and much safer to carry a pregnancy.

For obese patients I suggest the following;

  1. Your doctor may want to consider first trimester screening for gestational diabetes.
  2. An early ultrasound to establish the correct due date is essential.
  3. Obtain a consultation with a nutritionist. The goal isn’t to lose weight, but rather to eat a healthy diet and limit weight gain during pregnancy.
  4. For patients with a BMI between 30-40 with a singleton pregnancy, a total weight gain of 11-20 pounds is recommended (and 25-42 pounds for similar patient with twins).
  5. For patients with morbid obesity (BMI above 40kg/m2) no weight gain may be recommended. (One study of more than 100,000 obese patients noted a 5 kg weight loss was not associated with an increase in small for gestational age neonates, but was associated with a decreased risk of macrosomia.)
  6. If it is difficult to evaluate the top of the uterus (the fundus) to determine whether it is growing appropriately, consider serial ultrasounds to assess fetal growth.
  7. Consider meeting with anesthesia ahead of time to plan for pain control during labor.

Pregnancy is an exciting time, and if you enter a pregnancy carrying excess weight, it is important to make sure you and your doctor or midwife are doing everything necessary to assure a healthy outcome. And after you deliver, it’s time to resolve to lead a lifestyle that includes a healthy diet and plenty of exercise.

This entry was posted in Comfort Measures, gestational diabetes, In The News, Labor and Childbirth, obesity, pregnancy, Prenatal Nutrition, Preparing for Baby, Your Healthy Pregnancy. Bookmark the permalink. Post a comment or leave a trackback: Trackback URL.

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