August 26, 2013
Effective Epilepsy Drug Valproate May Cause Birth Defects
Brett Smith for redOrbit.com - Your Universe Online
The anti-seizure drug valproate has been shown to be extremely effective, but a new study has found that it increases the risk of pregnant women giving birth to a child with spina bifida or hypospadias when taken in higher doses.
The finding allows for women who suffer from seizures to make a more informed decision when deciding if they want to have a child.
"For many women on epilepsy medication, the desire to start a family can be fraught with fear that they could have a baby with a range of disabilities or malformations," said study co-author Terry O'Brien, an epilepsy specialist with The Royal Melbourne Hospital.
"Previous studies have shown a strong relationship between the dose of valproate taken and the risk of the child having a birth defect,” O’Brien added. “However, for many women valproate is the only drug that will help control their seizures.”
Spina bifida is an incurable, debilitating birth defect of the spine and spinal cord, which occurs in the first three months of pregnancy. Hypospadias is a birth defect of the penis that can be treated by corrective surgery.
"Through our research, we now know that by reducing the dose taken in the first trimester of pregnancy, the risk of having a baby with spina bifida or hypospadias will be greatly reduced,” O’Brien said.
The neurologist added that other birth defects such as cleft palates and heart defects were prevalent in women who took the anti-seizure drug, regardless of dosage.
The study was based on data from the Australian Pregnancy Register (APR), which included information on more than 1,700 women with epilepsy who have been or are currently pregnant. Based at The Royal Melbourne Hospital, the APR has gathered game-changing epilepsy data since 1999.
According to study author and epilepsy expert Frank Vajda, the study could make a significant difference for women with epilepsy and their families.
"We always knew that epilepsy drugs were responsible for the high level of fetal malformations but we never knew how much dosage played a role until recently," he said. "The present findings for spina bifida are clinically significant, as 80 percent of all instances of spina bifida in the APR were associated with valproate exposure.”
"However, since the collection of data for the APR started, we have noted that valproate was being taken less often by pregnant women and in lower dosages,” Vajda added. "This evidence now tells us that by using valproate in the lowest dose that can control severe seizures may reduce the hazard of one of the most devastating birth defects."
Despite its effectiveness, valproate has been the subject of a growing number of studies finding negative side effects of its use, particularly for unborn children. A study published by JAMA in April found a connection between a pregnant woman’s use of the drug and a higher risk of her child developing autism.
"There must be a continuous effort to include this information along with all the other risks in discussions with women of childbearing age who are candidates for valproate," said the study’s lead author Jakob Christensen.