NEW YORK, Feb. 12 (Xinhua) -- At-home DNA tests can not only find serial killers, but also help prevent premature births, Bill and Melinda Gates said in their 2019 annual letter released on Tuesday.
When police used genetic test results to catch the Golden State Killer last year, the story made headlines around the world. But it is not the only discovery to come out of at-home DNA tests, Bill Gates said in the letter.
By looking at more than 40,000 samples voluntarily submitted by "23andMe" users, scientists discovered a potential link between preterm labor and six genes, including one that regulates how the body uses a mineral called selenium. Some people have a gene that prevents them from processing selenium properly.
The "23andMe" study found that expectant mothers who carry that gene were more likely to give birth early. This suggests that selenium plays a role in determining when a woman begins labor.
Understanding what causes prematurity is hugely important, Bill Gates said, explaining that 15 million babies are born prematurely every year, making it the leading cause of death in children under age five.
He said researchers do not know how exactly the mineral affects preterm birth risk. But if the link proves substantial, selenium could one day be a cheap and easy solution to help women extend their pregnancies to full term.
"This connection is one of several breakthroughs we've made in recent years. Better tools and more data sharing mean that we're finally starting to understand what causes babies to be born early and what we can do to keep them in the womb longer," he said.
"I'm particularly excited by the simple blood test for prematurity being developed by a team at Stanford. It can tell a woman how soon she'll give birth, so she can work with her doctor to minimize risks."
Melinda Gates said that despite all the promising discoveries, "what's just as amazing to me is how little we know about prematurity."
For example, it is a mystery why taller women have longer pregnancies. Also, in the United States, it is a mystery why African-American women deliver prematurely more often than women who emigrate to the United States from African countries.
One theory is sociocultural -- that the racism and discrimination African-American women have faced in their whole lives leads to stress that damages their health. Another is that the mix of micro-organisms in women's bodies may be different when they are raised in the United States, she said.
"It matters a lot how early a baby is born; a baby born at 36 weeks is much better off than a baby born at 34 weeks," she said. "Our goal should not be to prevent prematurity categorically, which may be impossible anyway. Instead, it should be to extend pregnancies closer to full term for everyone. And we're finally starting to fill the gaps in our knowledge about how to do so."