The Latest News From the CDC on Birth Defect Risks

Written by yvonnethornton on March 5th, 2011

In a report published in the American Journal of Obstetrics and Gynecology, the Centers for Disease Control (CDC) [] warned against using prescription opiate-based painkillers such as codeine, hydrocodone or oxycodone (brand names include Vicodin and Oxycontin) during pregnancy.

According to an article about the CDC report:

In the study of data from 10 states, the CDC researchers found that 2 percent to 3 percent of mothers interviewed received prescription opioid pain killers, or analgesics, just before they got pregnant or early in their pregnancy. Any illicit use of painkillers was not assessed.

For those women, the risk of having a baby with hypoplastic left heart syndrome — a critical heart defect — was about double that of women who took no opioid drugs.

Risks of other birth defects, including spina bifida (a type of neural tube defect), hydrocephaly (build up of fluid in the brain), congenital glaucoma (eye defect), and gastroschisis (a defect of the abdominal wall), also somewhat increased among babies whose mothers took these drugs either shortly before or during pregnancy.

I have concerns about the generalization of both articles, but the conclusions may be valid. Taking a drug before you’re pregnant, or up to 17 days after conception, is unlikely to cause birth defects. It will either cause a miscarriage or will have no effect. But because most women don’t know precisely when they conceived, it’s best to avoid taking drugs at any time during pregnancy.

The greatest risk to a developing baby from a pregnant mother taking potentially toxic drugs occurs between 17 days post-conception to 12 weeks (end of the first trimester).

You’ve probably heard of Thalidomide, a sedative given in the 1950s to pregnant women in their first trimester. It dramatically illustrated the risks to a fetus’s development from drug effects during the critical first weeks. Thalidomide given early in pregnancy stunted the development of babies’ arms, legs, hands and feet, and caused other limb deformities.

If you’re pregnant, or planning to be, you should also be aware that most drugs, whether prescription or over-the-counter can have unknown effects on a growing fetus. The bottom line is: Every drug is, in some sense, a poison. Don’t consider any drug safe in pregnancy unless prescribed by someone who knows its toxicity as well as the risks and benefits of the drug.

– Yvonne S. Thornton, MD, MPH


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