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Date of last update: 10/14/2017.

Forum Name: Obstetrics

Question: Metronidazole (Flagyl) during conception

 mvsp - Tue Feb 17, 2009 11:28 am

Hi, I was taking Metronidazole for bacterial vaginitis DURING conception and for the following week. I have read that it is most dangerous during the first few weeks of pregnancy. I'm trying to decide whether to keep the pregnancy or not and possible effects are important in my decision.
 Debbie Miller, RN - Thu Mar 05, 2009 2:39 pm

User avatar Hello,
Be careful about what you read. Often data is incomplete, biased or just plain outdated. OTIS (Organization of Teratology Information Specialists) who are experts when it comes to safety in pregnancy has said this:
"Use of metronidazole has been controversial over the years. Older studies have
suggested an association between metronidazole and an increase in various birth
defects. However, these studies had flaws that make it difficult to be sure if those birth defects were caused by metronidazole. In contrast, recent studies and reviews that examined the cases of thousands of women exposed to this
drug in early pregnancy could find no evidence that using metronidazole during pregnancy increases the risk for major malformations or other adverse effects on the fetus. While some sources still state that this drug should not be used during the first trimester or at all in pregnancy, the current data do not support a significant increased risk for birth defects or other adverse effects on the fetus... since the drug is considered safe to use orally, both vaginal and
topical use should not pose an increased risk to your pregnancy."

This is consistent with my information and experience. In actuality there are very few drugs that have actually been found to cause defects, especially among the legal substances, even in the early days following conception. The scare comes from the unknown since actual scientific studies are not performed on pregnant women. However, after many thousands of women have had such exposures, the teratology organizations that study this are able to reassure us that relatively few pose a threat. Also, animal studies have never been a good indicator of the effects on humans. Besides, they are exposed to doses much higher than would ever be prescribed to women.

This would not be a reason for terminating a pregnancy.

I hope this helps. Best wishes.

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