What are the risk factors for stillbirth?

Stillbirth can happen in any pregnancy. Even after an autopsy and other tests, the cause of stillbirth may not be known.1

Research shows that some factors increase the risk for stillbirth among U.S. women, while other factors may increase risk among women worldwide. Here, we focus on U.S. risk factors. Many of these factors are not changeable, meaning there is nothing the pregnant woman, her family, or her health care provider can do to prevent the stillbirth.

Despite some known risk factors, most U.S. stillbirths occur in pregnant women who don’t have any risk factors.2

Risks for Stillbirth in the United States

Studies have found several factors that increase risk for stillbirths among pregnant women in the United States. However, these factors do not cause stillbirths; they only increase the chances that one will occur.2,3,4,5

Features of the Pregnant Woman or the Pregnancy

  • Low socioeconomic status
  • Age 35 years or older
  • Tobacco, marijuana, or alcohol use during or just before pregnancy6
  • Exposure to secondhand smoke during pregnancy
  • Illegal drug use before or during pregnancy7
  • Black/African American race/ethnicity8
  • Certain medical conditions or diseases, such as diabetes or high blood pressure before pregnancy and some infections9
  • Having overweight or obesity
  • Never having given birth before
  • Previous pregnancy loss, miscarriage, or stillbirth
  • Previous low birth weight or small infant for the stage of pregnancy, called small for gestational age (SGA)
  • Pregnancy with twins, triplets, or other multiples
  • Using assisted reproductive technology
  • Stressful life events, such as major financial, emotional, traumatic, or partner-related events, in the year before pregnancy10
  • Environmental exposures, including pollution and high temperatures11

For the fetus, one known risk factor for stillbirth is small size, sometimes called SGA. SGA can result from growth restriction, a condition in which the fetus does not grow as quickly or as well as it should because of a problem with the pregnancy.

Citations

  1. The Stillbirth Collaborative Research Network Writing Group. (2011). Causes of death among stillbirths. Journal of the American Medical Association, 306(22), 2459–2468. Retrieved August 23, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562291
  2. The Stillbirth Collaborative Research Network Writing Group. (2011). Association between stillbirth and risk factors known at pregnancy confirmation. Journal of the American Medical Association, 306(22), 2469–2479. Retrieved August 23, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3807602
  3. Flenady, V., Koopmans, L., Middleton, P., Frøen, J. F., Smith, G. C., Gibbons, K., et al. (2011). Major risk factors for stillbirth in high-income countries: a systematic review and meta-analysis. The Lancet, 377(9774), 1331–1340. Retrieved August 23, 2023, from https://pubmed.ncbi.nlm.nih.gov/21496916/
  4. Varner, M. W., Silver, R. M., Rowland Hogue, C. J., Willinger, M., Parker, C. B., Thorsten, V. R., et al; Stillbirth Collaborative Research Network. (2014). Association between stillbirth and illicit drug use and smoking during pregnancy. Obstetrics & Gynecology, 123(1), 113–125. Retrieved August 23, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3931517/pdf/nihms542706.pdf (PDF 731 KB)
  5. McClure, E. M., Nalubamba-Phiri, M., & Goldenberg, R. L. (2006). Stillbirth in developing countries. International Journal of Gynaecology and Obstetrics, 94(2), 82–90. Retrieved August 23, 2023, from https://pubmed.ncbi.nlm.nih.gov/16730726/
  6. NICHD. (2021). Media Advisory: Drinking and smoking during pregnancy linked with stillbirth, NIH-funded study suggests. U.S. Department of Health and Human Services, National Institutes of Health. Retrieved August 23, 2023, from https://www.nichd.nih.gov/newsroom/news/082321-stillbirth-risk
  7. NICHD. (2013). Tobacco, drug use in pregnancy can double risk of stillbirth. U.S. Department of Health and Human Services, National Institutes of Health. Retrieved August 23, 2023, from https://www.nichd.nih.gov/newsroom/releases/121113-stillbirth-drug-use
  8. MacDorman, M. F., & Gregory, E. C. W. (2015). Fetal and perinatal mortality: United States, 2013. National Vital Statistics Reports, 64(8). Retrieved August 23, 2023, from https://www.cdc.gov/nchs/data/nvsr/nvsr64/nvsr64_08.pdf (PDF 1.4 MB)
  9. NICHD. (2018). Media Advisory: Pregnancy loss occurs in 26 percent of Zika-infected monkeys. U.S. Department of Health and Human Services, National Institutes of Health. Retrieved August 23, 2023, from https://www.nichd.nih.gov/newsroom/news/070218-zika-pregnancy-loss
  10. NICHD. (2013). Stressful life events may increase stillbirth risk, NIH network study finds. U.S. Department of Health and Human Services, National Institutes of Health. Retrieved August 23, 2023, from https://www.nichd.nih.gov/newsroom/releases/032713-stillbirth-stress
  11. NICHD. (2017). NICHD research links air pollution and extreme temperature to stillbirth risk. U.S. Department of Health and Human Services, National Institutes of Health. Retrieved August 23, 2023, from https://www.nichd.nih.gov/newsroom/releases/091917-podcast-stillbirth
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