Use and safety of calcium channel blockers in obstetrics.

Calcium-Channel Blockers (CCBs), or calcium antagonists, are a heterogeneous group of drugs that produce cardiovascular effects by preventing the influx of calcium ions through L-type voltage-dependent calcium channels in specialized electrical system and conduction tissue cells, like myocardial and vascular smooth muscle cells. In recent years, CCBs have found their way in obstetrics and gynecology, especially in the management of hypertensive disorders of pregnancy and preterm labor. The lack of adequate data had created uncertainty about the safety of CCBs in pregnancy. Teratogenicity with these agents has been demonstrated in animals, but no cases of possible human malformation or deformity have been reported. Data from human studies suggest that CCBs may cause a clinically insignificant fall in maternal mean arterial pressure, but have little to no effect on uterine perfusion. In many countries, CCBs remain unlicensed for use in pregnancy and it is unlikely the manufacturers will ever apply for this status to change. We do believe that this is the situation of CCBs for those critical second- and third-trimester conditions such as Gestational hypertension, Preeclampsia, HELLP syndrome and preterm labor.