The decline varied in each country, but was generally sizeable. In Bangladesh, for example, about 34 percent of women reported being married by age 14 in 1991 and 1994. By 2005 and 2007 that number fell to about 19 percent.

The news, however, was not good for older girls, researchers said.

"The decrease for the youngest age group is dramatic, but for the oldest, we've got nothing," said Anita Raj, the study's lead author and a professor at the University of California, San Diego School of Medicine.

Raj and her colleagues report in a letter to the editor of the Journal of the American Medical Association that marriage rates for girls between the ages of 16 and 17 years old stayed about the same, except for about a 36 percent increase in Bangladesh -- a country that generally has a higher marriage prevalence for girls under 18 years old.

For their study, the researchers analyzed surveys taken between 1991 and 2007 in the four countries. For marriage rates, they looked at whether 20- to 24-year-old women reported being married before their 18th birthday.

For girls younger than 14 years old, the falls in girl marriage ranged from about 35 percent in India to 61 percent in Pakistan.

In India, the rate for that age group dropped from about 10 percent between 1991 and 1994 to about six percent between 2005 and 2007.

Pakistan saw its marriage rate among girls younger than 14 years old fall from about six percent to a little less than three percent.

While the data can't say why marriage rates for that age fell over the two decades, Raj told Reuters Health that it might be from girls wanting to complete their education first. Students in those countries typically graduate from high school at the age of 15 or 16.

Bangladesh, India and Nepal all ban marriage before the age of 18, and Pakistan's minimum age is 16. But Raj said those are largely ignored -- especially in rural areas.

HEALTH CONCERNS

Beyond legal issues, there are many health concerns when a girl marries, including complications from pregnancy and physical abuse.

Teen mothers are at a higher risk for pregnancy-induced high blood pressure, delivering babies before 37 weeks and their child having a low birth weight, said Monica Johnson, a women's health nurse practitioner at the Barnes-Jewish Hospital's teen pregnancy center in St. Louis.

The teens are also at risk for postpartum depression, Johnson told Reuters Health.

She added that "with adequate prenatal care and emotional support a lot of those teen moms do not experience the risks."

In a previous article, however, Raj reported that the poorest and least educated girls are at the greatest risk for an early marriage. That may limit access to healthcare.

SUB-SAHARAN AFRICA

Raj and her colleagues focused on South Asia mostly because of the amount and quality of data available, but she said that based on her experience early marriage should not be seen as a problem exclusive to that area.

A 2011 report from UNICEF -- a child rights group -- reported that adolescent marriage is also common in sub-Saharan Africa. It adds that the psychosocial effects girls experience are enormous, including not having friends, being powerless and doing an excessive amount of housework.

Raj told Reuters Health that one way to reduce marriage among young girls may be to increase the amount of choices they have, such as access to schools or a job.

SOURCE: bit.ly/JOTmp1 Journal of the American Medical Association, online May 15, 2012.

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