Femara during Pregnancy & Breastfeeding

by on June 17, 2012

Because medications taken by a woman during pregnancy have the potential to affect a developing fetus, the US Food and Drug Administration have assigned drugs various categories detailing whether they have the potential to be harmful during pregnancy or not. Femara (letrozole) has been categorised as a class D drug. This means that there have been studies or case-reports demonstrating that this medication can cause harm to a developing fetus, but may still be used during pregnancy if the mother requires it.

If you are taking Femara to treat breast cancer and have only recently started going through the menopause (peri-menopausal), you should use contraception. This is because although fertility is reduced when going through the menopause, there is still the potential to become pregnant until you become fully menopausal. You should contact your physician for further advice if this relates to you.

Femara during Pregnancy

Femara’s main use is to treat breast cancer in post-menopausal women. It is very unlikely that any woman using the medication for this reason would become pregnant. It is also used off-label as a female fertility treatment, in short five day bursts at certain points during a woman’s cycle. If you are using it as a fertility aid and become pregnant, your doctor should advise you to stop taking the medication. There is a potential for a woman to use the medication to increase fertility without knowing that she is pregnant.

There have been no human studies on the effects of Femara in pregnant women. However, animal studies have shown that the medication is harmful to a developing fetus, and should not be used.

Femara and Breastfeeding

Similarly, it is unlikely that Femara will be used as a medication for women who are breastfeeding because it is intended for use in post-menopausal women with estrogen-dependent breast cancer. It is sometimes used by specialist physicians as a fertility aid, but you should have stopped treatment with it when you become pregnant. If you are breast-feeding and are taking Femara you should speak to your physician as to why this is, to determine if the risks of the medication outweigh your health benefits.

It is not known if Femara is present in human breast milk, or of the effect this will have on your child. However many drugs are present in breast milk. If you are taking Femara whilst breast-feeding, then you can take the following steps to minimise any harmful effects of Femara on your child. You should speak to your doctor about taking the lowest possible dose of Femara that still controls your symptoms. In addition, it is important to plan at what time of day you will take the medication. If you take it at the beginning of the longest possible time before the child feeds again, for example just after a feed, or when the child is asleep, then the majority of the medication will have cleared from your body before the child feeds again. This will ensure that your baby is exposed to the minimum amount of medication, whilst you still get the drug that you need.