This sheet is about exposure to penicillin G 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 provider.
What is penicillin G?
Penicillin G is an antibiotic medication in the penicillin family. It works by killing bacteria that cause infections, including Staphylococcus aureus (Staph) and syphilis. Penicillin G is given intravenously (I.V.), meaning it is injected into a vein.
Sometimes when women find out they are pregnant, they think about changing how they take their medication or stopping it 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 the benefits of treating your condition and the risks of untreated illness during pregnancy.
Treating infections during pregnancy is important because untreated infections, such as Staph or syphilis, can increase the chance of pregnancy complications or health problems for a newborn. Syphilis can also pass to the developing baby during pregnancy. MotherToBaby has fact sheets on Staph https://mothertobaby.org/fact-sheets/staphylococcus-aureus-pregnancy/ and syphilis https://mothertobaby.org/fact-sheets/syphilis/.
Some people are allergic to penicillin. Rarely, penicillin G can cause anaphylaxis, a severe allergic reaction that may cause trouble breathing, low blood pressure, dizziness, fainting, or nausea. If you think you may be allergic to penicillin, talk with your healthcare provider about the best treatment option.
I take penicillin G. Can it make it harder for me to get pregnant?
Studies have not been done to see if taking penicillin G can make it harder to get pregnant.
Does taking penicillin G increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. Taking penicillin G in pregnancy is not expected to increase the chance of miscarriage.
Does taking penicillin G 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 penicillin G, might increase the chance of birth defects in a pregnancy. Multiple studies have looked at the use of penicillin G during pregnancy and have not reported an increased chance of birth defects.
Does taking penicillin G in pregnancy increase the chance of other pregnancy-related problems?
Penicillin G is not expected to cause other pregnancy-related problems, such as preterm delivery (birth before week 37 of pregnancy) or low birth weight (weighing less than 5 pounds, 8 ounces [2,500 grams] at birth).
Does taking penicillin G in pregnancy affect future behavior or learning for the child?
Information from limited studies does not suggest that taking penicillin G during pregnancy would increase the chance of behavior or learning issues for the child.
Breastfeeding while taking penicillin G:
Limited information suggests that penicillin G passes into breast milk in small amounts. Taking penicillin G is not expected to cause side effects in most infants. Babies who are exposed to penicillins through breast milk might have diarrhea or develop thrush (a fungal infection in the mouth). If you suspect the baby has any symptoms (such as diarrhea, white spots in the mouth, or mouth pain), contact the child’s healthcare provider. Be sure to talk to your healthcare provider about all your breastfeeding questions.
If a man takes penicillin G, could it affect fertility or increase the chance of birth defects?
Studies have not been done to see if penicillin G could affect a man’s fertility (ability to make healthy sperm) or increase the chance of birth defects. In general, exposures that men have are less likely 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/.
If you are taking penicillin G for an infection that can be passed to others by sexual contact (such as syphilis), it is important to treat your infection for your own health and for your partner’s health. Passing infections on to a woman who is pregnant might increase risks to a pregnancy. Your healthcare provider can talk with you about what steps can be taken to help prevent sexual transmission of infections to your partner.
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