azathioprine
Azathioprine is used with other medications to prevent transplant rejection (attack of the transplanted organ by the immune system) in people who received kidney transplants. It is also used to treat severe rheumatoid arthritis (a condition in which the body attacks its own joints, causing pain, swelling, and loss of function) when other medications and treatments have not helped. Azathioprine is in a class of medications called immunosuppressants. It works by decreasing the activity of the body's immune system so it will not attack the transplanted organ or the joints.
Full drug information on MedlinePlus →This is general information, not medical advice. Pregnancy and breastfeeding decisions should always be made with your healthcare provider.
Can taking azathioprine affect fertility or make it harder to get pregnant?
It is not known whether taking azathioprine or 6-MP can make it harder to become pregnant. If you have questions about fertility while using this medication, it is best to discuss them with your healthcare provider.
Does taking azathioprine increase the risk of miscarriage?
Miscarriage can happen in any pregnancy for many different reasons. The fact sheet notes that taking azathioprine or 6-MP is not expected to increase the chance of miscarriage. Any specific concerns should be reviewed with your healthcare provider.
Does taking azathioprine increase the risk of birth defects?
Every pregnancy starts with a background 3–5% chance of a birth defect. Azathioprine and 6-MP have been studied in over 1,500 pregnancies and have not been shown to increase the chance of birth defects, and where some studies found increases, these were generally similar to rates in people with the same underlying conditions and showed no consistent pattern. Your healthcare provider can help weigh these findings against the benefits of treating your condition.
Can taking azathioprine during pregnancy cause other pregnancy-related complications?
Some studies have reported higher rates of preterm birth (before 37 weeks) or low birth weight (under 2500 g), although it is unclear whether this relates to the medication, the underlying illness, or other factors. Use near delivery has also been associated with temporary immune system effects and low blood counts in the newborn, which seems more likely with higher doses or when the pregnant person has low white blood cells. These considerations are best discussed individually with your healthcare provider.
Can taking azathioprine during pregnancy affect the child's brain development, learning, or behavior?
The fact sheet states that studies have not been done to see if azathioprine or 6-MP can cause behavior or learning issues in children exposed during pregnancy. Any questions about long-term child development should be raised with your healthcare provider.
Is it safe to breastfeed while taking azathioprine?
Small amounts of azathioprine and 6-MP have been found to pass into breast milk in people who break the medication down as expected, with the highest levels around 1–2 hours after a dose and very small amounts by about 4 hours after. Most babies exposed through breast milk have had normal blood counts and have not shown higher rates of infection. Decisions about breastfeeding while taking this medication should be made together with your healthcare provider.
Source: National Library of Medicine
azathioprine