Pregnancy, breastfeeding and fertility while taking losartan

Losartan and pregnancy

Losartan is not recommended in pregnancy. It can reduce the level of fluid around your baby, particularly if you take it in the second and third trimesters of pregnancy. This can result in long-term damage to your baby's kidneys and lungs and a number of other problems.

If you're already pregnant, stop taking losartan and talk to your doctor straight away. Usually, your doctor will be able to prescribe a different medicine that is safer to take in pregnancy. Losartan should always be stopped by the time you're 12 weeks pregnant.

Use contraception if you're taking losartan and carefully plan any pregnancy with your doctor, obstetrician or hospital specialist. They will review your medical condition and medicine before you get pregnant.

Most women come off losartan before getting pregnant, but some may continue up until they have a positive pregnancy test and then stop. Your doctor will discuss what's best for you, based on your medical condition and the risks and benefits of losartan.

Losartan and breastfeeding

It might be OK to take losartan while breastfeeding, but talk to your doctor or pharmacist first. It is best not to take losartan if your baby was born prematurely, but your doctor will help you decide.

It is not known how much losartan gets into breast milk, but it's likely to be a small amount. However, there is a very small risk that it could also lower your baby's blood pressure. Until we know more about losartan in breastfeeding, your doctor might recommend a different medicine for you to take.

If you notice that your baby is not feeding as well as usual, seems unusually sleepy, looks much paler than normal, or if you have any other concerns about your baby, talk to your health visitor, midwife or doctor as soon as possible.

Losartan and fertility

There's no evidence to suggest that taking losartan reduces fertility in either men or women.

However, if you're trying to get pregnant, talk to your doctor first as they may wish to switch you to a different medicine that can be taken in pregnancy.

For more information about how angiotensin receptor blockers (ARBs) like losartan can affect you and your baby during pregnancy, visit the Best Use of Medicines in Pregnancy (BUMPS) website.