How many people are at risk of having a high-risk pregnancy?

The more risk factors a woman has, the more likely she and her fetus will be at risk during pregnancy and birth. Statistics are available for some risk factors:

  • High blood pressure. According to statistics collected by the National Heart, Lung, and Blood Institute, about 6% to 8% of pregnant women in the United States have high blood pressure. About 70% of them are women who are pregnant for the first time.1
  • Preeclampsia. Preeclampsia affects an estimated 3% to 5% of pregnancies in the United States, and 5% to 10% of all pregnancies globally.2 The majority occur at term.
  • Multiple births (twins). The National Center for Health Statistics reported that between 1980 and 2009, the twin birth rate increased 76%—from 19 to 33 per thousand births.3 For women between the ages of 35 and 39, twin births rose by 100%, and for women aged 40 and older, the increase in twin births was more than 200%.4 The increase in multiple births is due in part to the use of fertility treatments, especially in women older than age 35.
  • Gestational diabetes. According to the Centers for Disease Control and Prevention (CDC), gestational diabetes affects 2% to 10% of pregnancies.5
  • Women between the ages of 40 and 44. The CDC also reported that the birth rate for women in their early 40s increased to 10.2 births per 1,000 women in 2010, the highest rate since 1967. This increase is attributable at least in part to the expanded use of assisted reproduction technology (fertility treatments).6

  1. National Heart, Lung, and Blood Institute. (n.d.). How common are high blood pressure and preeclampsia in pregnancy? Retrieved June 17, 2012, from
  2. Omole-Ohonsi, A., & Ashimi, A.O. (2008). Pre-eclampsia: A study of risk factors. Nigerian Medical Practitioner, 53, 99–102. Retrieved August 7, 2012, from Web Site Policy
  3. Martin, J. A., Hamilton, B. E., & Osterman, M. J. K. (2012). Three decades of twin births in the United States, 1980-2009. NCHS data brief, no 80. Hyattsville, MD: National Center for Health Statistics.
  4. MedlinePlus. (n.d.) Twins, Triplets, Multiple Births. Retrieved June 13, 2012, from
  5. National Institute of Diabetes and Digestive and Kidney Diseases, National Diabetes Information Clearinghouse. (n.d.) National Diabetes Statistics, 2011. Retrieved June 17, 2012, from
  6. Hamilton, B. E., Martin, J. A., & Ventura, S. J. (2011). Births: Preliminary data for 2010. National Vital Statistics Report, 60, 1–25.

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