A recent study has shown that there is a nine-year “just right” Goldilocks zone when it comes to the best age for women to have a baby.
This ideal age range for childbearing is between 23 and 32 years, according to researchers as this group had the lowest risk of birth defects.
The study, performed at Semmelweis University in Hungary, analysed data from over 31,000 births with confirmed non-chromosomal birth defects recorded in their database from 1980 to 2009, and compared this with the more than 2.8 million births registered in the country over that same 30-year period.
They found that teenage moms and women in their early 20s were more likely to give birth to children with defects of 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.
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 per cent in women above the age of 32 when compared to those within the optimal age window.
In the study, younger moms were 25 per cent more likely to see defects such as spina bifida, compared to older mothers. Women who gave birth younger than 20 saw an even greater risk of these problems relative to women 23 to 32.
Older mothers, on the other hand, were twice as likely to have a baby with malformations of the eyes, ears, face, and neck caused by an infant’s skull or facial bones fusing too soon or in an abnormal way. Women on the older end of the spectrum were also more likely to see heart defects as well as more malformations of the urinary system than those in the healthy age window.
And older mothers had a considerably higher likelihood—45 per cent in fact—of giving birth to a baby with a cleft lip and palate, while a younger mother’s risk increased by nine per cent.
Dr Boglárka Pethő, assistant professor at Semmelweis University and the first author of the study said, “We can only assume why non-chromosomal birth anomalies are more likely to develop in certain age groups.
“For young mothers, it could be mainly lifestyle factors (eg, smoking, drug or alcohol consumption) and that they are often not prepared for pregnancy.
“Among advanced-aged mothers, the accumulation of environmental effects such as exposure to chemicals and air pollution, the deterioration of DNA repair mechanisms, and the ageing of the eggs and endometrium can also play a role.”
The result of this study comes as the average age of mothers in many countries continues to rise. For instance, women in the USA are now giving birth for the first time at approximately age 30, up from 27 in 2000 and 24 in 1970, and generally, birth rates are falling worldwide.
A baby boom in the mid-20th century saw the average woman give birth to between three and four children. Today, just 1.6 children—the lowest level recorded since data was first tracked in 1800.
Even here at home, it comes as no surprise as I continue to see women who are opting to delay motherhood. This has been attributed to several factors such as changing family values, women prioritising their careers, and the rising cost of living, not to mention the increasing control that women can exercise over their reproductive lives and rightly so.
However, even before this new study was published, it was already well known that women who get pregnant and give birth beyond age 35 typically have more dangerous pregnancies. Older mothers may be at increased risk of miscarriage, high blood pressure, gestational diabetes, and difficult labour.
Previous research has also confirmed the association between older maternal age and certain genetic disorders, namely Down’s syndrome, for which the risk increases from about one in 1,250 for a woman who conceives at age 25, to about one in 100 for a woman who conceives at age 40.
Ultimately, age is just one factor that should go into the decision to get pregnant. Emotional and financial readiness is also crucial, and that timing is unique for each woman. These findings of the new study may play a role in guiding this decision-making.
