Not expecting: What may be behind high rates of unintended pregnancy in the U.S.

Yasamin Kusunoki, 2014-2015 winner of an Award from the Marshal Weinberg Endowed Research Fund, is studying dynamic patterns of contraceptive use among young women during the transition to adulthood.

Yasamin Kusunoki. Photo by Michael McIntyre/ISR

Yasamin Kusunoki. Photo by Michael McIntyre

Before coming to Michigan as a postdoc, Yasamin Kusunoki was already interested in the topic of contraceptive use. Adolescent sexual behavior and reproductive health were her research focus at UCLA, where she received a Ph.D. in Public Health in 2007. But as Co-Investigator with ISR sociologist Jennifer Barber (Principal Investigator) and other ISR colleagues on an innovative longitudinal study of 1,003 young women — the Relationship Dynamics and Social Life Study (RDSL) – Kusunoki gained a deeper understanding of how relationships affect the chances that young women will have unprotected sex, use more or less effective methods of birth control, and ultimately experience an unintended pregnancy.

Just how likely unintended pregnancies still are in the U.S. surprises a lot of people. A recent study published in the New England Journal of Medicine found that the rate had fallen to a 30-year low in 2011, but even so, an astonishing 81 percent of pregnancies among women who were cohabiting were unintended.

How can this be in 21st century America, with so many kinds of contraceptives available? Young women may not have easy access to, or be able to afford, highly effective types of contraception, such as birth control pills or IUDs, injections and other long-acting reversible contraceptives, Kusunoki points out. Or norms about using contraceptives may not support their use.

But Kusunoki’s recent analysis of the RDSL data, funded partly by the Marshall Weinberg Endowed Research Fund, shows that another factor may be even more important.

“We learned that the types of relationships young women are in can have a major effect on their use of contraception,” says Kusunoki.

Analyzing the detailed information study participants provided in weekly journals over a period of two-and-a-half years, Kusunoki and colleagues found that three main aspects of a relationship had a major impact on contraceptive use: the level of seriousness or commitment, the amount of instability, and the level of violence or aggression. And the connections weren’t always what they expected.

The more serious the relationship, the more likely young women are to use the pill, Kusunoki found. The less serious the relationship, the more likely the couple will use condoms, or rely on withdrawal.

Relationship stability is also important, according to Kusunoki. About 32 percent of the young women in relationships during the study reported that they broke up with their partners, then got back together sometime during the study period. “It’s surprisingly common,” said Kusunoki. “And with prior break-ups, young women are less likely to use contraception at all, and when they do, they’re more likely to rely on less effective methods, like condoms and withdrawal.”

The level of relationship violence and aggression reported by the young women in the study may also surprise some people. Overall, 45 percent of the young women reported experiencing physical or psychological violence from their partners during study period. “If there was a history of violence in the relationship,” said Kusunoki, “the young women were less likely to use contraceptives, less likely to use contraceptives consistently, and more likely to use withdrawal as a contraceptive method.”

Why would young women be more likely to risk an unintended pregnancy in relationships characterized by instability and violence?

In a pilot study Kusunoki is currently conducting in reproductive health settings, she found that about 20 percent of young women interviewed worried about using contraception because they thought their partners would not approve of it. Providers at the clinics were surprised the incidence was so low, according to Kusunoki. They thought it would be much higher, based on the number of young women who came in saying things like, “I need a shot so he won’t know I’m using contraception,” or “I need the strings on my IUD really short so he can’t feel it.”

Kusunoki and colleagues have spent a lot of time talking about the best ways to help women match their pregnancy intentions to their behaviors. So moving into translational research, to see how interventions work – or don’t work – in a reproductive health setting, is a natural progression.

In addition to her appointment as a Faculty Associate at the ISR Population Studies Center and Survey Research Center, Kusunoki became an Assistant Professor at the U-M School of Nursing this academic year. “It’s exciting to help students understand how we can use evidence to support changes in practice and policy,” she says. “The application of research knowledge is becoming increasingly important to me. I appreciate those on the ground, and hope I can be useful as a liaison between researchers and practitioners.”

Kusunoki with her daughters, Lily and Stella. Photo courtesy of Yasamin Kusunoki.

Kusunoki with her daughters, Lily (left) and Stella. Photo courtesy of Yasamin Kusunoki.

Becoming a mother strengthened Kusunoki’s intention to use research to improve the reproductive health of young women. She and her husband, James Billingslea, have five-year-old identical twin girls, Stella and Lily. “I’m incredibly grateful that my husband is able to stay at home with the girls right now before they transition to school. It was very important to both of us that one of us could be with them at this stage in the life course. He is an amazing father,” she says. “With spring hopefully in our future, we look forward to doing things together outdoors – visiting the Cobblestone Farm Market is one favorite activity. Our families don’t live here, so we’ve cultivated a wonderful community of friends,” says Kusunoki. “Ann Arbor is a great place to raise a family.”

Not expecting: What may be behind high rates of unintended pregnancy in the U.S.