A study has found that the ideal age range for mothers to give birth is between 23 and 32, as it is associated with lower chances of non-chromosomal issues in babies.

The study, published in the journal Nature, found that the risk of fetal abnormalities, called non-chromosomal anomalies (NCAs), was lowest for women aged between 23 and 32. Women older than 32 had a 15% higher chance of such births, while younger mothers had a 20% higher chance.

As part of the study, researchers looked at data from 2.8 million pregnancies between 1980 and 2008. They looked into the age of the women when they gave birth, and calculated the risk of having a baby with a non-chromosomal anomaly at each age. The researchers then found that, on average, about 1 in 100 babies had one of these conditions.

As maternal age increased, the babies became more susceptible to Down's Syndrome, heart conditions and cleft lip and palate, while younger mothers saw central nervous system defects in their children, the study from the Semmelweis University in Budapest found.

Speculations suggest the reason behind the increased risk in older women is likely due to the age of their eggs. On the other hand, the higher risk in younger women might be linked to factors like smoking, drug use, and alcohol consumption, although the study did not delve into the specific causes.

The causes of NCAs are also thought to include maternal infection, poor diet, and exposure to toxins, pollutants, or radiation during fetal development. However, determining the specific trigger for each case is often unknown.

However, more research would be required to further understand how the age of the expectant mother during childbirth specifically impacts the likelihood of these conditions occurring in newborns.

"This is an interesting study including a very large number of babies," Asma Khalil, vice president for academia and strategy at the UK's Royal College of Obstetricians and Gynecologists, told New Scientist. However, "the risks to the babies born to mothers outside of the [23 to 32] age range are still small."

According to New Scientist, the chances of a woman under the age of 23 having a child with NCA is about 1.2 in 100.