What Causes Cleft Lip and Cleft Palate?
Clefts can be caused by genetic or environmental factors. It is unclear what exactly causes the birth defect. Numerous studies have linked the use of antidepressants during pregnancy with a higher risk of certain birth defects.
Cleft lip and cleft palate have also been associated with women’s use of the anticonvulsant drug, Topamax (topiramate) during pregnancy. Studies have linked the use of Topamax during pregnancy with a higher risk of cleft lip and cleft palate.
Disturbing Links Between Topamax and Cleft Lip / Cleft Palate
Topamax (topiramate) is an antiepileptic drug (AED) made by Ortho-McNeil Pharmaceuticals, a Johnson & Johnson subsidiary. It is approved for the treatment of epilepsy and for the prevention of migraines. Topiramate is also prescribed off-label for unapproved uses, including weight loss and the management of alcohol dependence.
Unfortunately, babies exposed to Topamax during pregnancy are 21 times more likely to have a cleft lip or cleft palate, according to the North American Antiepileptic Drug (NAAED) Pregnancy Registry.
Topiramate and Pregnancy: What You Need to Know
The FDA issued a Topamax warning on March 4, 2011 informing the public of the new data that show that there is an increased risk for development of cleft lip and/or cleft palate (oral clefts) in newborns born to women treated with topiramate (Topamax and generic products) during pregnancy. Both cleft lip and cleft palate can lead to numerous developmental, psychological and social delays.
Topiramate was previously classified as a Pregnancy Category C drug, which means that data from animal studies suggested potential fetal risks, but no adequate data from human clinical trials or studies were available at the time of approval. However, because of new human data that show an increased risk for oral clefts, topiramate is being placed in Pregnancy Category D. Pregnancy Category D means there is positive evidence of human fetal risk based on human data but the potential benefits from use of the drug in pregnant women may be acceptable in certain situations despite its risks. The change in pregnancy category will appear in the new prescribing and labeling information of the medication.
The prevalence of oral clefts was 1.4% compared to a prevalence of 0.38% – 0.55% in infants exposed to other antiepileptic drugs (AEDs), and a prevalence of 0.07 % in infants of mothers without epilepsy or treatment with other AEDs. The relative risk of oral clefts in topiramate-exposed pregnancies in the NAAED Pregnancy Registry was 21.3 as compared to the risk in a background population of untreated women (95% Confidence Interval:7.9 – 57.1). The UK Epilepsy and Pregnancy Register reported a similarly increased prevalence of oral clefts (3.2 %) among infants exposed to topiramate monotherapy, a 16-fold increase in risk compared to the risk in their background population (0.2%).