Pregnancy and obesity: Know the risks

Concerned about pregnancy and obesity? Understand the risks of obesity during pregnancy — plus steps to promote a healthy pregnancy. By Mayo Clinic Staff

Being obese during pregnancy can have a major impact on your health and your baby's health. Find out about the possible complications, recommendations for weight gain and what you can do to promote a healthy pregnancy.

What's considered obese?

Obesity is defined as having an excessive amount of body fat. A formula based on height and weight — called the body mass index (BMI) — is often used to determine if a person is obese.

BMIWeight status
Below 18.5 Underweight
18.5-24.9 Normal
25-29.9 Overweight
30 and higher Obese
40 and higher Extreme obesity

Could obesity affect my ability to get pregnant?

Being obese can harm your fertility by inhibiting normal ovulation. Obesity can also affect the outcome of in vitro fertilization (IVF). As a woman's BMI increases, so does the risk of unsuccessful IVF.

How might obesity affect my pregnancy?

Being obese during pregnancy increases the risk of various pregnancy complications, including:

  • Gestational diabetes. Women who are obese are more likely to have diabetes that develops during pregnancy (gestational diabetes) than are women who have a normal weight.
  • Preeclampsia. Women who are obese are at increased risk of developing high blood pressure and protein in the urine after 20 weeks of pregnancy (preeclampsia).
  • Infection. Women who are obese during pregnancy are at increased risk of urinary tract infections. Obesity also increases the risk of postpartum infection, whether the baby is delivered vaginally or by C-section.
  • Thrombosis. Women who are obese during pregnancy are at increased risk of a serious condition in which a blood clot forms inside a blood vessel (thrombosis).
  • Obstructive sleep apnea. Women who are obese during pregnancy might be at increased risk of a potentially serious sleep disorder in which breathing repeatedly stops and starts (obstructive sleep apnea). Pregnancy might also worsen existing obstructive sleep apnea.
  • Overdue pregnancy. Obesity increases the risk that pregnancy will continue beyond the expected due date.
  • Labor problems. Labor induction is more common in women who are obese. Obesity can also interfere with the use of certain types of pain medication, such as an epidural block.
  • C-section. Obesity during pregnancy increases the likelihood of elective and emergency C-sections. Obesity also increases the risk of C-section complications, such as delayed healing and wound infections. Women who are obese are also less likely to have a successful vaginal delivery after a C-section (VBAC).
  • Pregnancy loss. Obesity increases the risk of miscarriage and stillbirth.
Dec. 28, 2012 See more In-depth