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Metronidazole (Buy Flagyl) and Pregnancy
This sheet talks about the risks that exposure to metronidazole can have during pregnancy. With each
pregnancy, all women have a 3% to 5% chance of having a baby with a birth defect. This information should not
take the place of medical care and advice from your health care provider.
What is metronidazole?
Can taking metronidazole during pregnancy
cause birth defects or other adverse effects on
Metronidazole is an antibiotic used to
the baby?
treat different kinds of infections. It is available
in oral, rectal, vaginal and topical preparations.
Use of metronidazole has been
Metronidazole is commonly used for vaginal
controversial over the years. Older studies have
infections for which pregnant women can
suggested
an
association
between
require treatment. It has been on the market for
metronidazole and an increase in various birth
more than 40 years. Another name for
defects. However, these studies had flaws that
metronidazole is Buy Flagyl.
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
Can taking metronidazole when planning a
drug in early pregnancy could find no evidence
pregnancy make it more difficult for me to
that using metronidazole during pregnancy
become pregnant?
increases the risk for major malformations or
other adverse effects on the fetus. While some
There is no research addressing this
sources still state that this drug should not be
issue; however, there is currently no evidence
used during the first trimester or at all in
to suggest that metronidazole would cause
pregnancy, the current data do not support a
difficulties getting pregnant.
significant increased risk for birth defects or
other adverse effects on the fetus.
Can taking metronidazole during early
What if I use it topically (on the skin) or
pregnancy increase the risk for miscarriage?
vaginally?
No. There is one large study that looked
Topical preparations of metronidazole
at over 4000 pregnancies with exposure to
are minimally absorbed and not likely to result
metronidazole early in pregnancy and did not
in a significant level in your blood. However,
find an increased risk for miscarriage.
vaginal use of metronidazole may result in a
more significant absorption of the medication
into your system. Yet, since the drug is
considered safe to use orally, both vaginal and
topical use should not pose an increased risk to
your pregnancy.
Can I take metronidazole any time during
Burtin P, et al. 1995. Safety of metronidazole in
pregnancy?
pregnancy: a meta-analysis. Am J Obstet Gynecol
172(21):525-529.
Currently there is no evidence to
Cantu JM and Garcia-Cruz D. 1982. Midline facial
suggest that metronidazole places a pregnancy
defect as a teratogenic effect of metronidazole. Birth
at risk at any stage. For some conditions,
Defects 18:85-88.
metronidazole is the only drug of choice and it
is especially important to treat vaginal
Caro-Paton T, et al. 1997. Is metronidazole teratogenic?
A meta-analysis. Br J Clin Pharmacol 44:(2)179-182.
infections during pregnancy.
Czeizel AE and Rockenbauer M. 1998. A population
based
case-control
teratologic
study
of
oral
I have heard that this drug may cause cancer.
metronidazole. Br J Obstet Gynecol 105(3):322-327.
Is this true?
Finegold SM. 1980. Metronidazole. Ann Intern Med
93:585-587.
Metronidazole has been shown to cause
both changes in genetic material and cause
Hale T. 2006. Medications and Mothers Milk. Amarillo,
cancer in animals. It has not yet been found to
TX: Pharmasoft Medical Publishing, pp 598-600.
have these effects in humans. One study that
Kazy Z, et al. 2005. Teratogenic potential of vaginal
followed several hundred women for twenty
metronidazole treatment during pregnancy. Eur J Obstet
years did not find an increase in cancer.
Gynecol Reprod Biol. 2005 123(2):174-178.
Passmore CM, et al. 1988. Metronidazole excretion in
Can I take metronidazole while breastfeeding?
human breastmilk and it's effect on suckling neonates.
British J Clin Pharmacol 26(1):45-51.
Metronidazole is excreted into breast
Piper JM, et al. 1993. Prenatal use of metronidazole and
milk in relatively large amounts, with some
birth defects: no association. Obstet Gynecol 82(3):348-
reports of up to 20% of the mother's dose.
352.
However, this dose is well below the
Rosa FW, et al. 1987. Pregnancy outcomes after first
therapeutic dose given to treat young infants
trimester vaginitis drug therapy. Obstet Gynecol 69:751-
who were able to tolerate this drug with no side
755.
effects. In addition, a study of 12 women who
were taking metronidazole three times per day
did not find adverse effects on the breastfed
babies.
If you have questions about the information on
this fact sheet or other exposures during
pregnancy, call OTIS at 1-866-626-6847.
October 2006.
Copyright by OTIS.
Reproduced by permission.
References:
Beard CM, et al. 1988. Cancer after expsoure to
metronidazole. Mayo Clinic Proceedings 63(2):147-153.
Beard CM, et al. 1979. Lack of evidence for cancer due
to use of metronidazole. N Engl J Med 301:519-522.