Federal drug regulators approved Topamax (and its generic equivalent, Topiramate) as an anti-epileptic drug and for prevention of migraines. On March 4, 2011, The FDA announced that Topamax would carry a pregnancy “Category D” warning which means that there is positive evidence of human fetal risk. Other Category D drugs include alcohol, lithium and most chemotherapy drugs to treat cancer.
This month the Therapeutic Goods Administration (TGA), Australia’s regulatory authority similar to the FDA, followed suit and announced a change in pregnancy category for Topamax (topiramate). The Australian Pregnancy Category D is defined as:
Drugs which have caused, are suspected to have caused or may be expected to cause, an increased incidence of human fetal malformations or irreversible damage. These drugs may also have adverse pharmacological effects.
Data from pregnancy registries indicate that infants exposed to Topamax in utero have an increased risk of cleft lip and/or cleft palate. Oral clefts happen early in pregnancy, before many women even know they are pregnant. For this reason, women of childbearing age need to be extremely careful when taking Topamax.
Babies with cleft lips and/or palates have feeding difficulties, increased ear infections and the cleft palate often affects a child's speech, since the palate is necessary for speech formation. Although surgery is often used to close the lip and palate, the child's speech pattern may still be affected despite surgical repair.
Children born to pregnant women who took Topamax may also have other birth defects including limb malformations and hypospadias (an anomaly in which the urethra opens on the ventral surface of the penis).