Opioid Use and Neural Tube Defects

The journal Obstetrics and Gynecology has published a new study that looked at the use of opioids during pregnancy and their relationship to having a pregnancy affected by a neural tube defect (NTD). Researchers from Boston University and CDC found that mothers who used opioids in the first two months of pregnancy were two times more likely to have a pregnancy affected by an NTD than mothers who didn’t use opioids during pregnancy. You can read the abstract of the article hereexternal icon. Read more below for a summary of findings from this article.

Pregnant woman taking medication

Main Findings from this Study

  • Mothers with pregnancies affected by an NTD reported opioid use more often during the first two months of pregnancy than mothers of babies without an NTD.
  • Reasons for taking opioids varied, but pain (joint or muscle pain, sprains, injury, backache, arthritis, cramps, or other unspecified pain) was the most reported reason.
  • The results of this study are similar to previous studies that looked at opioid use during pregnancy and the risk of NTDs, specifically a study done by CDC using data from the National Birth Defects Prevention Study (NBDPS). This study also found that mothers who were treated with opioid medicines during the first trimester (first three months) of pregnancy were twice as likely to have a pregnancy affected by spina bifida than mothers who didn’t use opioids during the first trimester1.

About this Study

  • The aim of this study was to examine if a woman’s use of opioids during the first two months of her pregnancy was linked to the risk for NTDs in her unborn baby.
  • Researchers used data on babies that were due to be born between 1998 and 2010 from the Slone Epidemiology Center Birth Defects Studyexternal icon, an ongoing study of birth defects in the United States and Canada. The Birth Defects Study collects information on pregnancies affected by birth defects and babies born without birth defects in order to study what might cause or prevent birth defects.
  • Participating U.S. and Canadian cities were Boston, Philadelphia, Toronto, and San Diego. Birth defect registries in Massachusetts and New York were also included.
  • Researchers analyzed the following NTDs in this study: spina bifida, anencephaly, and encephalocele.
  • Opioids that were reported in this study include codeine, oxycodone, hydrocodone, morphine, propoxyphene, meperidine, methadone, tramadol, hydromorphone, butorphanol, heroin, fentanyl, buprenorphine, nalbuphine, and diphenoxylate.
Making Treatment Decisions

When making treatment decisions just before or during pregnancy, it is important that women and their doctors weigh the benefits of prescription pain medications along with the potential risks for both the woman and her unborn baby.

Treating for Two: Safer Medication Use in Pregnancy

Our Work

CDC’s National Center on Birth Defects and Developmental Disabilities (NCBDDD) is working to improve the health of women and babies through its Treating for Two: Safer Medication Use in Pregnancy initiative. Treating for Two works to understand trends in medicine use among pregnant women and women of reproductive age, and provide women and healthcare providers with information about the safety or risk of using specific medicines during pregnancy. This information will allow women and their doctors to make informed decisions about treating health conditions during pregnancy.

For more information, visit www.cdc.gov/treatingfortwo.

Reference for Key Findings

Yazdy MM, Mitchell AA, Tinker SC, Parker SE, Werler MM. Periconceptional use of opioids and the risk of neural tube defects. Obstetrics and Gynecology. 2013: epub ahead of print.


  1. Broussard CS, Rasmussen SA, Reefhuis J, Friedman JM, Jann MW, Riehle-Colarusso T, Honein MA, National Birth Defects Prevention Study. Maternal treatment with opioid analgesics and risk for birth defects. American Journal of Obstetrics and Gynecology. 2011;204(4):314.e1-11.