[Maternal age and neural tube defects: evidence for a greater effect in spina bifida than in anencephaly].

Background: Recent evidence from birth order data suggest that maternal factors can differently influence anencephaly and spina bifida.

Aim: To study the influence of maternal age on the risk for neural tube defects.

Material And Methods: A meta-analysis of published data on neural tube defects (NTDs) was carried out to determine whether there is an increased risk to have a child with NTDs for younger and older mothers and if this risk differs depending on the type of NTD. All data available with information regarding the frequency of live births and NTDs cases by maternal age (five- or ten-year intervals) were included in the analysis. Effect sizes calculations were performed.

Results: The analysis supports the hypothesis that there is an increased risk of having an offspring with NTDs for mothers 40 years of age or older. However, this effect is stronger for spina bifida than for anencephaly. There is also evidence that mothers 19 years old or younger have a higher risk for having a child with spina bifida.

Conclusions: Maternal age influences the risk of having an offspring with neural tube defects.