The American Journal of Obstetrics and Gynecology has published a new CDC study: “Maternal Treatment with Opioid Analgesics and Risk for Birth Defects”. You can read the abstract of the article here. The findings from this article are summarized in the following text.

Opioid analgesics are prescription medications that commonly are used to treat severe pain. Two common opioid medications are codeine and oxycodone. Lower doses of opioids also might be included in some cough medicines. The effects of opioids on a pregnant woman and her unborn baby are not well understood. Previous studies looking at opioid analgesics and birth defects have had inconsistent findings. However, some have suggested that these medications might increase the risk for heart defects or cleft lip and palate.

For this study, researchers aimed to see if treatment with any opioid analgesic medication just before or during early pregnancy was associated with the occurrence of certain birth defects. The study used data from the National Birth Defects Prevention Study, a population-based, case-control study to understand the causes of and risk factors for major birth defects in the United States. Population-based means that the study looked at all babies with birth defects whose mothers lived in the study region, which is important to make sure that study results apply to the U.S. population in general.

Main findings from this study include:

• Treatment with opioid analgesics was linked with the following birth defects:
  
  
  • Spina bifida (a type of neural tube defect)
  • Hydrocephaly (build up of fluid in the brain)
  • Glaucoma (an eye defect)
  • Gastroschisis (a defect of the abdominal wall)
  • Congenital heart defects
    • Conoventricular septal defect
    • Atrioventricular septal defect
    • Hypoplastic left heart syndrome
    • Atrial septal defect
    • Tetralogy of Fallot
    • Pulmonary valve stenosis
      
      
• Treatment with opioid analgesics just before or during early pregnancy was reported by 2% to 3% of the mothers.
  
  
• Codeine and hydrocodone were the most frequently reported medications, representing 69% of all reported opioid analgesics used.
  
  
• Commonly reported reasons for treatment with opioid analgesics during pregnancy included surgical procedures, infections, chronic diseases, and injuries.
  
  

The findings related to congenital heart defects were consistent with findings of previous studies showing links between the use of codeine during the first trimester and the occurrence of some heart defects. Congenital heart defects are among the most common birth defects, affecting nearly 1% of U.S. births, and are the main contributor to infant death attributable to birth defects. As mentioned earlier, previous studies have suggested that treatment with opioid analgesics might increase the risk for cleft lip and palate. However, in this study, the occurrence of cleft lip and palate did not appear to be linked with treatment with opioid analgesics.

In this study, the findings related to some of the other birth defects were observed for the first time. For example, links between the use of opioid analgesics and the occurrence of hydrocephaly, glaucoma, or gastroschisis have not been observed in previous studies and deserve further investigation.

Medication during pregnancy: CDC activities

The Centers for Disease Control and Prevention (CDC) is committed to working with its partners and the public to build a comprehensive approach to understanding and communicating the risks of birth defects that potentially are associated with the use of medications, such as opioid analgesics, during pregnancy.

• Research: As mentioned previously, CDC funds a large study of birth defects called the National Birth Defects Prevention Study. This study is working to identify risk factors for birth defects and to answer questions about some medications taken during pregnancy, including opioid analgesics.
  
  
• Technical expertise: CDC works with the U.S. Food and Drug Administration, drug manufacturers, and other professionals to help conduct studies on the effects of medication use during pregnancy and ways to prevent harmful effects.

More Information

To learn more about medication use during pregnancy, please visit http://www.cdc.gov/pregnancy/meds/index.html.
For more information about birth defects, please visit CDC's birth defects homepage.

Reference

• Broussard CS, Rasmussen SA, Reefhuis J, Friedman JM, Jann MW, Riehle-Colarusso T, Honein MA, for the National Birth Defects Prevention Study. Maternal treatment with opioid analgesics and risk for birth defects. Am J Obstet Gynecol. 2011 [Epub ahead of print].