USE OF VIGABATRIN IN PREGNANCY

Vigabatrin is an anticonvulsant used predominantly in combination with other antiepileptic drugs (AEDs) in the treatment of resistant partial seizures, with or without secondary generalisation, where all other potential drug combinations have proved ineffective, are contraindicated, or not tolerated.

There is very limited information on the use of vigabatrin in pregnancy. Fetal toxicity and congenital malformation has been reported in animal studies. An initial report by the manufacturer of high rates of congenital malformation among children exposed in utero is likely to be heavily biased by concomitant maternal medication use and retrospective reporting.

The very limited available data, derived from isolated case reports, small uncontrolled case series, cohort studies and a network meta-analysis do not currently provide reputable evidence which demonstrates that vigabatrin use in pregnancy increases the risk of congenital malformation, miscarriage, intrauterine fetal death, preterm delivery or intrauterine growth restriction. However, given the available data is highly limited, it is not possible to exclude the risk of such effects and further studies are therefore required.

Vigabatrin therapy in the non-pregnant patient has been associated with retinal and optic atrophy, peripheral field loss and electroretinogram abnormalities. It is unknown whether in utero exposure is also associated with visual disturbance in the offspring and until further data are available the possibility of an effect on fetal visual development cannot be ruled out. 

Vigabatrin may impact upon maternal folate status. UK guidelines state that women who take any anti-epileptic medication should be prescribed high dose folic acid (5mg).

Use of any centrally acting drug throughout pregnancy or near delivery may be associated with withdrawal symptoms in the neonate and/or poor neonatal adaptation syndrome (PNAS). These symptoms are likely to be more severe in infants exposed in utero to more than one CNS acting drug. Delivery should be planned in a unit with neonatal intensive care facilities.

More research is required to define the pregnancy safety profile of vigabatrin. Pregnant women and women of childbearing potential should be made aware of the lack of data for all pregnancy outcomes. Vigabatrin should only be used during pregnancy where benefits of treatment are considered to outweigh any potential risks. In view of the limited human pregnancy data, close monitoring of mother and fetus should be considered with use of vigabatrin in pregnancy. Other risk factors may also be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.