Chelsea Bernhardt Polsi
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About Chelsea
Dr. Chelsea Polis is a reproductive health epidemiologist focusing on contraception, abortion, FemTech, infertility, and prevention of HIV and other STIs. Her systematic reviews have contributed to global WHO and CDC contraceptive guidance, and her research has been cited in over 160 policy documents in over 20 countries. In 2023, Dr. Polis was awarded a John Maddox Prize for her work identifying flawed research and misleading marketing by a fertility tracking device manufacturer. Her efforts led to retraction of the flawed paper and FDA-mandated marketing changes. She has testified to the FDA and briefed Congressional staff on evidence standards in reproductive health, and she advocates for anti-SLAPP laws to protect free speech for researchers and others. Dr. Polis holds a PhD from Johns Hopkins Bloomberg School of Public Health (where she holds an Associate appointment in the Department of Epidemiology) and a BA from Brown University.
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Examines how well fertility awareness–based methods work for preventing pregnancy when people track signs of their menstrual cycle. It finds that these methods can be quite effective when used carefully and consistently, but pregnancy risk is much higher when they’re used inconsistently or without proper guidance.
Looks at many studies to see whether having an abortion affects a woman’s long-term mental health. Finds that the better-designed research generally shows little to no difference in mental health between women who had abortions and those with unintended pregnancies carried to term, while weaker studies that did find negative effects were less reliable.
Looks at whether giving people a supply of emergency contraception ahead of time (so they have it before unprotected sex) helps prevent more pregnancies. Finds that although advance provision leads to people using the pills more often and sooner after sex, it does not lower overall pregnancy rates, and it doesn’t lead to riskier sexual behavior or change use of other birth control methods.