Study reveals ideal age to have a baby. A recent study of more than 31,000 births showed that women aged 23 to 32 had the lowest risk of birth defects.

Teenage mums and women in their early twenties were more likely to give birth to children with defects to the central nervous system, affecting things like brain and spine development, while mature pregnancies were associated most closely with deformities of the head, neck, eyes, and ears.

Young mums are often unprepared for pregnancy and have more unhealthy lifestyle factors such as drug and alcohol use, the researchers said.

Older women have been exposed to environmental stressors such as air pollution for longer, which the team believes may contribute to their risk of different birth defects.

For the latest study, scientists at Semmelweis University in Hungary analyzed data from 31,128 pregnancies with confirmed non-chromosomal birth defects recorded in an official Hungarian database between 1980 and 2009.

They compared that data with more than 2.8 million births registered in the country during that same 30-year period.

Overall, the risk of birth defects increased by about a fifth for births in women under the age of 22 compared to those within the ideal childbearing window of ages 23 to 32.

That risk increased by about 15 percent in women above the age of 32 when compared to those within the optimal age window.

The report was published in the journal BJOG: an International Journal of Obstetrics & Gynaecology.