Talking publicly about women's menstruation has long been a taboo. But in 2016 the world made big strides getting over the squeamishness. There was the Chinese swimmer at the Rio Olympics who had no qualms explaining that she was on her period after she finished a race grimacing in pain. Some medical students in India launched a "haiku" contest on menstruation. New York joined the growing number of states that have ended taxation of tampons and sanitary pads.The new openness has also sparked a widening conversation about how menstruation might affect girls in poor countries — their health, their confidence, even their education.Marni Sommer, a professor at Columbia University, was among the first social science researchers to look into this topic – and for a while, one of the only ones."When I started doing this in 2004 it was a pretty lonely world," she says.But not anymore. The work that she and other pioneers have done suggested that girls are having difficulty managing their periods — and it could be harming their education. And that's helped spur a groundswell of interest from girls' advocates, policy-makers, and researchers."Menstruation for sure is having its moment," says Sommer laughing.The early studies were generally in-depth surveys of girls mostly across Africa. The girls reported a range of concerns about their periods, including says Sommer, "fear, shame, embarrassment, impact on feelings of confidence."In a lot of cases, the girls said, they don't have access to products like pads and tampons, toilets at school, even basic information. So going to class during the menstrual period was a challenge."It's like the straw that breaks the camel's back," says Sommer. "There are many things that make going to school difficult and it's one more thing."That's a major concern, because compared to boys a much larger share of girls in poor countries drop out of high school.Enter Paul Montgomery, a professor at Oxford University who decided to test two options.The first was bringing in a community health worker to give girls a 75- minute lecture."We took a standardized education package that teaches girls about puberty," he explains. "And then more specifically how to handle periods."The second option was offering girls a pack of free, reusable sanitary pads called AFRIpads along with some soap to wash them and three pairs of underwear.So Montgomery and his collaborators recruited more than 1,100 girls roughly aged 10 to 13 in rural Uganda from eight schools and divided them into groups: Girls at the first group of schools got pads. Those in the second group got the education. The third group got both the education and the pads. The fourth group got nothing. The results, just out in the journal PLOS One are impressive.Over roughly two years, as the girls grew older and started to get their periods, their attendance rates dropped across the board. But that dip was a lot less dramatic for girls who got either the pads or the education or both. For instance, girls at the schools that got no help started out with a mean attendance rate of 83 percent. By the end of the study the rate was down to 62 percent.By contrast girls at the schools where pads were distributed started the study with a mean attendance rate of 67 percent. By the end of the study it had dropped by only about a percentage point to 66 percent."This is a really substantial improvement," says Montgomery. "I mean what we've shown here is that compared to doing nothing we can make a substantial difference by a simple intervention."But Montgomery also notes that there are a lot of caveats that point to the challenges of a study like this. So many girls drop out or transfer in that region of Uganda that the researchers ended up losing track of about 40 percent of the girls. Also more than half of those who were left in the study turned out to be too young to get their periods, says Montgomery."One of the difficulties is knowing the age of the girls where many of them don't know their own age."Columbia's Sommer says there's an additional obstacle for researchers: "We don't have good data on average age of menstruation in sub-Saharan Africa and many low income countries."Sommer would have also liked to see more information on other potentially crucial factors — how sensitive teachers at the school are about the menstruation challenge, for instance, or what the toilets at the school are like."If girls don't have a safe private place to manage their periods ... then even with supplies or even with education, they still will be hindered," says Sommer."I just want people to pay attention to toilets," she says. But, she adds with a sigh, somehow, "they're not sexy."Sommer says the upshot of all this is that it's still not possible to conclude that programs like the ones tested in the Uganda study will actually improve attendance rates for girls. What's needed, she says, are more studies with far larger sample sizes.Bethany Caruso echoes Sommer's assessment. She's a post-doctoral fellow at Emory University who researches girls' menstrual hygiene management needs in poor countries.But she believes that the Uganda study is enormously useful as a sort of road map for further research."It's a puzzle piece in a giant puzzle," she says. And by underscoring the issues that future investigators will have to confront, "it can help us learn more."At the same time, both Caruso and Sommer express mixed feelings about the whole effort to prove that helping girls with their periods boosts attendance."Everybody wants attendance data," says Sommer. "And when I say everybody I mean national governments, I mean policy-makers, I mean donors, I mean funders of research."On one level she says, it's understandable: In a world of limited resources it can be helpful to justify spending to improve girls' menstrual hygiene on the grounds that doing so also improves their attendance.But says Sommer, there's a danger. "I don't want a lot of people implementing huge projects that they evaluate and decide don't work — and sort of it gets thrown out the window, the whole issue — when in fact, maybe you're just asking the wrong questions."For instance, maybe the most serious impact on girls who are menstruating is not that they don't show up to school, but that their concern about leakages makes it harder for them to concentrate or dissuades them from participating in class.The researchers also question the very idea that there has to be some educational or health justification for spending aid dollars to help girls manage their period. It suggests this isn't worth doing for its own sake."I wonder if boys had a similar biological experience," muses Caruso. "If we would be going through so much effort trying to justify whether or not we were investing in giving them what they need." Copyright 2016 NPR. To see more, visit http://www.npr.org/.