Women in Ireland are being urged to start taking folic acid.
Doctors have made the appeal in light of a rise in neural tube defects among babies born in this country.
Studies at the Coombe Hospital in Dublin show just one in four mothers were taking folic acid - which can prevent the problems - before they conceived.
A third of pregnancies in Ireland are unplanned, so experts say anyone who could potentially get pregnant, needs to be taking the supplement.
UCD Professor of Obstetrics Michael Turner spoke to Pat Kenny today about the issue and he says it's clear that folic acid is vital in the early days of pregnancy: