Molar pregnancy is uncommon, occurring in about 1 in every 1,000 pregnancies. Various factors are associated with molar pregnancy, including:

  • Maternal age. A molar pregnancy is more likely for a woman older than age 35 or younger than age 20.
  • Previous molar pregnancy. If you've had one molar pregnancy, you're more likely to have another. A repeat molar pregnancy happens, on average, in 1 to 2 out of every 100 women.
  • Some ethnic groups. Women of Southeast Asian descent appear to have a higher risk of molar pregnancy.
Nov. 11, 2011