Women having children at young ages and in rapid succession has been linked to higher infant mortality rates in South Asia.

In countries like Bangladesh, India, Nepal and Pakistan, one in 14 young mothers have a child that passes away before the age of one, a University of California, San Diego news release reported.

The researchers concluded children of women that gave birth below the age of 18 and had 24 months or less between pregnancies accounted for about one-quarter of all infant mortality rates among young mothers in India and Pakistan. This number represents about 200,000 in 2012 across only those two nations.

In Bangladesh only short breaks between pregnancies were linked to a higher mortality rate, while in Nepal only a younger pregnancy age was associated with higher instances of infant death.

"According to United Nations data, the infant mortality rate worldwide is 49.4 deaths per 1,000 live births. In Pakistan, it is 70.90; India, 52.91; Bangladesh, 48.98 and Nepal, 38.71. By comparison, the infant mortality rate in the United States is 6.81 and just 1.92 in Singapore, lowest in the world," the news release reported.

The research team analyzed demographic and health surveys from the included countries.

"The data in India and Pakistan were collected four to five years prior to the data in Bangladesh and Nepal," Anita Raj, PhD, professor of medicine and director of the Center on Gender Equity and Health at UC San Diego, said. "And therefore represent different cross-sections of time. In addition, both India and Pakistan have higher burdens of infant mortality - in absolute and relative terms - than Bangladesh or Nepal."

Raj believes the study's findings highlight the issues associated with young brides in said countries. A past study from the same lead researcher found 10 million girls under the age of 19 married globally every year. Child brides are more likely to "die young, suffer from serious health problems, live in poverty and remain illiterate."

"There is inadequate recognition that issues like early marriage of girls are primary drivers of problems like infant mortality in the region," Raj said.

Bangladesh and Nepal have made some improvements, including better access to education and healthcare for women.