This sheet is about exposure to nitrofurantoin in pregnancy and while breastfeeding. This information is based on published research studies. It should not take the place of medical care and advice from your healthcare providers.
What is nitrofurantoin?
Nitrofurantoin is an antibacterial medication that has been used to treat urinary tract infections (UTIs). Some brand names are Macrobid®, Macrodantin®, and Furadantin®.
Sometimes when women find out they are pregnant, they think about changing how they take their medication, or stopping their medication altogether. However, it is important to talk with your healthcare providers before making any changes to how you take your medication. Your healthcare providers can talk with you about using nitrofurantoin and what treatment is best for you.
The American College of Obstetricians and Gynecologists (ACOG) states that it is “reasonable to offer” nitrofurantoin in the first trimester when other medication is not available. ACOG also states that the use of nitrofurantoin in the second and third trimester has been considered a first-line treatment for UTIs.
The product label for nitrofurantoin recommends that woman who are near the end of their pregnancy (38 to 42 weeks’ gestation) or are otherwise close to delivery should not use this medication. This is because there is a risk of anemia (low number of red blood cells) in the newborn. However, the benefit of using nitrofurantoin might outweigh possible risks. Your healthcare provider can talk with you about using nitrofurantoin and what treatment is best for you.
I take nitrofurantoin. Can it make it harder for me to get pregnant?
It is not known if nitrofurantoin can make it harder to get pregnant.
Does taking nitrofurantoin increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. Two studies including 173 pregnancies did not find an association with nitrofurantoin use and an increased chance for miscarriage. However, women with untreated urine infections might have a greater chance for miscarriage.
Does taking nitrofurantoin increase the chance of birth defects?
Birth defects can happen in any pregnancy for different reasons. Out of all babies born each year, about 3 out of 100 (3%) will have a birth defect. We look at research studies to try to understand if an exposure, like nitrofurantoin, might increase the chance of birth defects in a pregnancy.
Some studies on nitrofurantoin have suggested an increased chance of birth defects with use in pregnancy. However, study design flaws make some of the results in these studies questionable. There are also many studies on nitrofurantoin use in pregnancy that did not find birth defects. Overall, an increased chance for birth defects has not been confirmed.
Does taking nitrofurantoin in pregnancy increase the chance of other pregnancy-related problems?
It is not known if nitrofurantoin can cause other pregnancy-related problems, such as preterm delivery (birth before week 37) or low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth). However, women with untreated urine infections might have a greater chance for these and other pregnancy complications, including preeclampsia (high blood pressure and problems with organs, such as the kidneys) that can lead to seizures (called eclampsia), and cesarean section (C-section).
Does taking nitrofurantoin in pregnancy affect future behavior or learning for the child?
Studies have not been done to see if nitrofurantoin can cause behavior or learning issues for the child.
Breastfeeding while taking nitrofurantoin:
Nitrofurantoin gets into breast milk in small amounts. In a report on 6 women taking nitrofurantoin while breastfeeding, 2 noted that their children had diarrhea. When any antibiotic is taken during breastfeeding, babies can be watched for diarrhea, vomiting, or rash.
The product label for nitrofurantoin recommends women who are breastfeeding should not use this medication when infants are less than 1 month old or if the nursing infant has a diagnosis of glucose-6-phosphate dehydrogenase deficiency (G6PD). This is because of a risk of hemolytic anemia (breakdown of red blood cells) in the child. But the benefits of treating your condition with nitrofurantoin, as well as the benefits of breastfeeding, may outweigh possible risks. Use of nitrofurantoin while breastfeeding an older infant without G6PD is unlikely to cause side effects. Your healthcare providers can talk with you about using nitrofurantoin and what treatment is best for you while you are nursing. Be sure to talk to your healthcare provider about all your breastfeeding questions.
If a man takes nitrofurantoin, could it affect his fertility or increase the chance of birth defects?
When nitrofurantoin was given to men at doses higher than typical for 2 weeks, sperm production was low or stopped in 13 out of the 36 study participants. Low sperm production could affect male fertility (ability to make healthy sperm). However, the use of typical doses of 100mg twice a day for 1 week did not have the same effect. This means that with typical use, nitrofurantoin is unlikely to affect male fertility. In general, exposures that men have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.
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