Is Amoxicillin Safe to Take During Pregnancy or While Breastfeeding?

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Antibiotics are some of the most frequently prescribed drugs for pregnant women. Amoxicillin is an antibiotic that is very similar to penicillin. It works by blocking bacterial cell wall production, leading to cell breakdown and bacterial death. Amoxicillin is often prescribed for the treatment of respiratory and urinary tract infections and is frequently prescribed to pregnant women for treatment of these conditions. While amoxicillin is often assumed to be safe in pregnancy, it does transfer from the mother’s bloodstream to the placenta, and therefore it is important to recognize the potential risks associated with the use of amoxicillin in pregnancy.

Amoxicillin is classified by the United States Food and Drug Administration (FDA) as Pregnancy Category B. This means that multiple studies of the use of amoxicillin in pregnant animals have not shown fetal harm to occur after the mother takes amoxicillin, but there are not adequate or well-controlled studies of the use of amoxicillin in pregnant women. In animal studies, the use of amoxicillin at doses up to 10 times the standard human dose was not associated with reproductive harm. A few human studies found that amoxicillin might be associated with birth defects, specifically cleft palate, when used in the first trimester of pregnancy during the period of fetal organ development. Multiple other human studies have not demonstrated any harmful effects of amoxicillin on fetal development.

Amoxicillin is often prescribed in combination with another antibiotic called clavulanic acid. Clavulanic acid prevents amoxicillin from being broken down by certain enzymes, making this combination of drugs more effective against resistant bacteria than amoxicillin alone. The combination of amoxicillin and clavulanic acid is known as Augmentin®. Like amoxicillin, there are scant data suggesting that the use of clavulanic acid in pregnancy is harmful to the fetus. Overall, the use of amoxicillin, with or without clavulanic acid, can be considered as generally safe in pregnant women.

If a woman takes amoxicillin before realizing that she is pregnant, there is likely nothing to worry about in terms of fetal health and safety. The health and development of a fetus is largely dependent on its mother, so it’s very important for pregnant women and women of childbearing age to stay as healthy as possible. Sometimes, this may include taking antibiotics like amoxicillin.

Amoxicillin is also safe to use in women who are breastfeeding. Its physical characteristics, including low fat solubility, low protein binding, and acidic pH, limit its transfer into breastmilk. The American Academy of Pediatrics considers this drug to be safe to take when breastfeeding.

All drugs, including prescription medications, can cause unwanted and potentially dangerous side effects. Augmentin can rarely cause liver injury. In one study, an infant whose mother took Augmentin was noted to have abnormally high liver enzymes. The infant’s liver enzymes returned to normal after the mother stopped taking Augmentin. Both amoxicillin and Augmentin are also known to cause allergic reactions, including anaphylaxis, in susceptible individuals. Since the antibodies that cause anaphylaxis do not cross the placental barrier, the development of anaphylaxis in a fetus is extremely unlikely to occur. However, maternal anaphylaxis can cause abnormal blood flow to the uterus or womb. This can affect the fetus and result in brain swelling, neurological damage, and fetal death.

If you suspect an adverse reaction after taking amoxicillin, get an immediate personalized recommendation online or call Poison Control at 1-800-222-1222. Both options are free, confidential, and available 24 hours a day.

Kelly Johnson-Arbor, MD
Medical Toxicologist