Amoxicillin
Information last updated October 2024
Most pregnancies result in healthy babies, but there are chances of complications and unexpected outcomes. These chances are called baseline risks. In Canada, the baseline risk of major birth defects is 3-5%. This means that 3-5 out of 100 babies born in the general population will be born with a major birth defect. There are also baseline risks for miscarriages (15-25 out of 100 pregnancies), premature birth and other outcomes. The information provided will summarize if taking this drug is likely to change these risks.
Summary:
Studies looked at the rates of birth defects in over 28,000 pregnancies where amoxicillin was used alone or with clavulanic acid in the first trimester. Most studies found that taking amoxicillin during pregnancy does not increase the risk of major birth defects above the baseline risk. One study found a higher risk of orofacial clefts (an opening in the lip and/or roof of the mouth), but other better designed studies did not find this risk. The limited available information does not show increased risks of other adverse pregnancy outcomes. To see more details please click on the tabs below.
It is important to treat infections occurring during pregnancy. If infections are not treated, they may lead to complications for the pregnant individual and the developing baby.
Please consult with your health care provider if you are considering stopping or making any changes to your regular medications.
This information about amoxicillin is of a general nature and about medical use and does not replace the medical care and advice of your healthcare provider. For questions on dose, timing, side effects, interactions, etc. please consult your healthcare provider. Additionally, please read the patient insert provided with your medication.
Although participants in the studies referenced below may have used amoxicillin in various combinations, the studies usually do not provide detailed information on drug combinations. This makes it challenging to comment on the safety of using this medication in combination with others during pregnancy or lactation.
Amoxicillin belongs to the group of penicillin antibiotics. It is used to treat a wide range of infections that are caused by bacteria sensitive to amoxicillin. Amoxicillin is also available in combination with another antibiotic, clavulanic acid.
If the product you are using contains other active ingredients, please check our Exposures A to Z for available information on the ingredient(s).
Pronunciation
Studies looked at the rates of birth defects in over 28,000 pregnancies where amoxicillin was used alone or with clavulanic acid in the first trimester. Most studies found that taking amoxicillin during pregnancy does not increase the risk of major birth defects above the baseline risk.
One older study, that included a very small number of pregnancies exposed to amoxicillin, found an increased risk of orofacial clefts. Five better designed studies did not find an increased risk of orofacial clefts following exposure to amoxicillin in pregnancy. It is unknown whether the increased risk of orofacial clefts reported in this study may be related to the infection the antibiotic was used to treat. The lips and roof of mouth (palate) are formed by the 12th week of pregnancy. Once the lips and palate are formed, cleft lip and/or palate cannot occur.
If you are taking medications and you notice any new health concerns or symptoms in your nursing infant, please contact their health care provider. In case of emergency, please go to the emergency room or call 911.
People who are taking a medication or substance while providing their breastmilk to an infant need to know how much of the medication or substance is passing into their milk. One of the commonly used measurements to estimate this is the Relative Infant Dose (RID). The RID is estimated by comparing the dose of drug taken in by the infant through breastmilk to the dose that the nursing parent takes. Most medications with an RID of less than 10% are usually compatible with nursing a healthy infant. The RID does not need to be calculated for each person because most of the time it is expected to be similar to what has been found in research studies. We will provide the RID in the information below, when available.
Based on the available information, amoxicillin passes into breastmilk in small amounts, with an RID of less than 2%. Amoxicillin is also used in infants; the amount of amoxicillin that passes into breastmilk is less than 1% of what is usually given to an infant to treat an infection. There have been some reports of rash, diarrhea or thrush (yeast infection of the tongue and/or mouth) in infants exposed to amoxicillin through breastmilk. However, the symptoms are usually mild and nursing does not need to be stopped. Please reach out to a healthcare provider if you notice any changes in your baby.
Pregnancy:
Over 28,000 pregnancies with exposure to amoxicillin alone or in combination with clavulanic acid in the first trimester of pregnancy were included in published studies that examined the rates of birth defects. Based on the majority of the studies, taking amoxicillin during pregnancy is unlikely to increase the risk of major birth defects above the baseline risk.
One case control study, that included a very small number of pregnancies exposed to amoxicillin, found an increased risk of orofacial clefts. Five better designed studies did not find an increase in the risk following exposure to amoxicillin.It is unknown whether the increased risk of orofacial clefts reported in this study was confounded by the infection the antibiotic was given for. The lips and the palate are formed by the 12th week of pregnancy. Once the lips and palate are formed, cleft lip and/or palate cannot occur.
Approximately 400-700 (depending on the outcome examined) pregnancies exposed to amoxicillin were included in studies examining other pregnancy outcomes. These studies did not report higher rates of miscarriage, stillbirth, prematurity, or low birth weight with use of amoxicillin in pregnancy.
However, more data is needed to confirm that there is no increased risk of these outcomes associated with amoxicillin use.
Lactation:
One of the factors that helps to determine if a medication is compatible with nursing is the Relative Infant Dose (RID). The RID provides an estimate of infant’s exposure to a medication through breastmilk. It is the ratio between the infant’s and the nursing individual’s weight-adjusted doses. The infant weight adjusted dose is estimated based on the concentration of medication in breastmilk, and an assumption of infant daily milk consumption of 150 ml/kg/day. In general, for infants with normal growth and development, most medications with an RID of less than 10% are considered compatible with nursing. The RID does not account for infant’s drug metabolism, clearance, or infant blood levels. Although some variability may exist in the RID, in most cases the estimated RID is adequate for clinical purposes and does not need to be calculated for each individual. We will provide the RID in the information below, when available.
Based on the available limited information, amoxicillin passes into breastmilk in small amounts, with an estimated RID of less than 2%. The dose ingested by the infant through breastmilk is estimated to be less than 1% of a pediatric dose used to treat infections in infants. There have been some reports of rash, diarrhea or thrush in infants exposed to amoxicillin through breastmilk. However, the symptoms are usually not severe and do not require interruption of nursing.
Harm Reduction:
If your patient may be using drugs or medications not as indicated during pregnancy, while providing breastmilk to an infant, or parenting please click Harm Reduction for additional information. In case of emergency, please advise them to go to the emergency room or call 911.
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Disclaimer
First Exposure does not offer health care treatment. If you have an urgent question about your pregnancy or your baby’s health, you should contact your health care provider directly. If you don’t have a health care provider and you live in Ontario, you have a variety of health care options. In the case of an emergency, visit a hospital emergency room or call 911.