Safety of tacrolimus in pregnancy

I have a 30-year-old patient who had a kidney transplant 2 years ago. She is now planning a pregnancy. She has been treated with tacrolimus since her transplant. Will it be safe for the fetus if she continues to take it during the pregnancy or should she switch to a different antirejection medication?

If your patient is stable while taking tacrolimus, there is no reason to switch. The current available information does not suggest that tacrolimus increases the risk of major congenital malformations above the baseline risk in the general population. Premature birth and low birth weight are often reported in this population; however, these effects are frequently reported in pregnant transplant patients treated with other immunosuppressant agents and probably reflect the effects of the maternal condition. As there are some reports of hyperkalemia and renal impairment in infants exposed to tacrolimus in utero, kidney function and electrolytes should be monitored in exposed neonates.