Tysabri Use In Pregnancy & Lactation

Women of childbearing potential: If a woman becomes pregnant while taking this medicinal product, discontinuation should be considered. A benefit/risk evaluation of the use of this medicinal product during pregnancy should take into account the patient's clinical condition and the possible return of disease activity after stopping the medicinal product.
Pregnancy: Studies in animals have shown reproductive toxicity (see Pharmacology: Toxicology: Preclinical safety data under Actions).
Data from clinical trials, a prospective pregnancy registry, post-marketing cases and available literature do not suggest an effect of natalizumab exposure on pregnancy outcomes.
The completed prospective Tysabri pregnancy registry contained 355 pregnancies with available outcomes. There were 316 live births, 29 of which were reported to have birth defects. Sixteen of the 29 were classified as major defects. The rate of defects corresponds to the defect rates reported in other pregnancy registries involving MS patients. There is no evidence of a specific pattern of birth defects with this medicinal product.
There are no adequate and well-controlled studies of natalizumab therapy in pregnant women.
Thrombocytopenia and anaemia in infants born to women exposed to natalizumab during pregnancy were reported in the postmarketing setting. Monitoring of platelet counts and haemoglobin is recommended in neonates born to women exposed to natalizumab during pregnancy.
This drug should be used during pregnancy only if clearly needed. If a woman becomes pregnant while taking natalizumab, discontinuation of natalizumab should be considered.
Breast-feeding: Natalizumab is excreted in human milk. The effect of natalizumab on newborn/infants is unknown. Breast-feeding should be discontinued during treatment with natalizumab.
Fertility: Reductions in female guinea pig fertility were observed in one study at doses in excess of the human dose; natalizumab did not affect male fertility.
It is considered unlikely that natalizumab will affect fertility performance in humans following the maximum recommended dose.