Fertility Study Warns of Risks From Multiple Births

Like many women going through fertility treatments, Nikki David had one thought when she learned she was pregnant with twins: instant family.

"We were hoping it was twins," said Ms. David, a 33-year-old real-estate agent based in Cherry Hill, N.J., who had twin girls in June after getting pregnant through in vitro fertilization. "We can't necessarily afford to do this again. I would be older the next time around. The whole process of going through IVF again. There were so many reasons why we're like, 'Please let it be twins, please let it be twins.' "

While many women who struggle with infertility say having twins is a blessing, medical experts are increasingly calling for measures to be taken to reduce the country's rate of multiple births.

In an analysis posted online in April in the journal Fertility and Sterility, researchers from the Hastings Center, an independent bioethics research institute, and the Yale Fertility Center called for a number of policy changes to encourage doctors and patients to try to avoid multiple pregnancies. Multiples have a greater risk of preterm...