Letrovitae Use In Pregnancy & Lactation

Women of perimenopausal state or child-bearing potential: Letrozole should only be used in women with a clearly established postmenopausal status (see Precautions). As there are reports of women regaining ovarian function during treatment with letrozole despite a clear postmenopausal state at start of therapy, the physician needs to discuss adequate contraception when necessary.
Pregnancy: Based on human experience in which there have been isolated cases of birth defects (labial fusion, ambiguous genitalia), letrozole may cause congenital malformations when administered during pregnancy. Studies in animals have shown reproductive toxicity (see PHARMACOLOGY: Toxicology: Preclinical safety data under Actions).
Letrozole is contraindicated during pregnancy (see Contraindications and PHARMACOLOGY: Toxicology: Preclinical safety data under Actions).
Breast feeding: It is not known whether letrozole and its metabolites are excreted in human milk. A risk to the newborns/infants cannot be excluded.
Letrozole is contraindicated during breast-feeding (see Contraindications).
Fertility: The pharmacological action of letrozole is to reduce estrogen production by aromatase inhibitor. In premenopausal women, the inhibition of estrogen synthesis leads to feedback increases in gonadotropin (LH, FSH) levels. Increased FSH levels in turn stimulate follicular growth and can induce ovulation.