Older mothers may have babies who grow up healthier and better educated than infants born to women in their twenties, an international study found. 

While the risk of having a premature baby was stronger for both teen mothers and women 35 and older, the adolescents were also more likely than 20-somethings to have toddlers with stunted growth and children who become high school dropouts, the study found.

“Having an older mother seems to be good for child development as long as that older mother is well-resourced and does not have a large number of children to look after,” lead study author Caroline Fall, a researcher at the University of Southampton in the UK, said by email.

Fall and colleagues examined outcomes based on maternal age for 19,403 babies born in five low- and middle-income countries: Brazil, Guatemala, India, the Philippines and South Africa.

Data from each country were collected at various times between 1969 and 1989 using slightly different methods, but all participants had records for maternal age and some outcomes for most children at least through age two.

Mothers in the study were on average around 26 years old. Women in Brazil were the youngest, typically 25.8 years old, while women in Guatemala were the oldest at 27.2.

Children of mothers 19 and younger had a 20 to 30 percent increased risk of low birth weight and premature delivery, the study found.

These kids also had 30 to 40 percent greater odds of having stunted growth at age two and failing to complete secondary school.

Researchers also assessed mothers’ socioeconomic status based on education level, marital status, wealth, ethnicity and urban or rural residence. After adjusting for these factors, the advantages of older motherhood persisted.

One limitation of the study is that it lacked data on genetics, smoking and diet for the mothers, and feeding other than breast milk for the infants and children, the researchers acknowledge in The Lancet Global Health.

Worldwide last year, one in 20 babies was born to a mother aged 15 to 19, with even higher rates of teen parenthood in sub-Saharan Africa, Dr. Haroon Saloojee and Dr. Hoosen Coovadia, researchers at the University of the Witwatersrand in Johannesburg, note in an editorial accompanying the study.

Globally, there is less data on older women, but they note that in the U.S., first-time birth rates for women aged 35 to 39 increased nine-fold from the 1970s to 2012, currently accounting for about one in 100 first babies.

It’s possible that older mothers have a better understanding of which factors can promote healthy growth and development of their children, Coovadia said by email.

For many women, though, the ability to plan pregnancy for an ideal time may depend on factors not entirely in their control, Coovadia noted.

“A range of environmental determinants of a woman’s health, education, autonomy, employment, etc. can be controlled if society is engineered to provide the socioeconomic protections women need for realizing their potential for a safe pregnancy and delivery and a suitable setting for their growing babies and children,” Coovadia said.

Out of all these factors, education is probably the most important, he added. Women who aren’t able to control these variables, however, can still do a lot to improve outcomes for their children.

“Disadvantaged mothers can achieve much to help their offspring attain their potential through good nutrition, including breastfeeding – if possible for more than a year – and maintenance of good health and immunizations, and close attention to things that stimulate their children.”

The study was funded by the Wellcome Trust and the Bill and Melinda Gates Foundation, but the researchers note that these organizations had no involvement in the design, analysis or publication of the study.