- HMS Community Values
- Introduction to Clinical Research Training
- Medical Education
- United Kingdom Clinical Scholars Research Training
- Vanderbilt Hall
- What it Means to Be a Harvard Doctor
- Diversity Commitment
- Tuition, Fees, & Expenses
- Interview Day
- The Neighborhood
- Admissions FAQs
- Contact Admissions
- Financial Aid
- Office of the Registrar
- Campus Planning and Facilities
- Ombuds Office
- Committee on Microbiological Safety
- Human Resources
- The Academy
- Office for Academic and Clinical Affairs
- Joint Committee on the Status of Women
- Global Health Research Core
- Global Clinical Scholars Research Training Program
- HMA Standing Committee on Animals
- Office of Research Compliance
- Harvard Medical School Event Calendar
- Office of Diversity RIA Program
- The Dean's Perspective
- Department of Pathology
- Harvard Mahoney Neuroscience Institute
- OHRA Home
- Office of Research Subject Protection
- Tools and Technology
- Alumni Association
- Cancer Biology & Therapeutics Program
- Celiac Program
- Department of Medicine
- HMS Information Technology
- HMS TransMed Program
- Introduction to the Practice of American Medicine
- Office of Communications & External Relations
- Big Data In Healthcare
- Institutional Planning and Policy
- Master of Medical Sciences In Clinical Investigation
- Office of Global Education
- Portugal Clinical Scholars Research Training Program
- Safety Quality Informatics and Leadership
- South American Clinical Research Training Program | SACRT
- Shenzhen-HMS Initiative in International Education
- test page
- HMS Foundation Funds
- Contact @HMS
- Office of Global Education
- Human Resources
- Jobs @ HMS
- Dental Medicine
- Harvard University
- Contact us
Oral contraceptives taken just before or during pregnancy do not increase the risk of birth defects, according to a new study by researchers from Harvard Medical School, Harvard T.H. Chan School of Public Health and the Statens Serum Institut in Denmark.
They found that the prevalence of major birth defects was consistent (about 25 per 1,000 live births) across all pregnant women in the study population regardless of contraceptive use.
“Women who become pregnant either soon after stopping oral contraceptives, or even while taking them, should know that this exposure is unlikely to cause their fetus to develop a birth defect,” said first author Brittany Charlton, instructor in pediatrics at Harvard Medical School and Boston Children’s Hospital and a researcher in the Harvard Chan School Department of Epidemiology. “This should reassure women as well as their health care providers.”
The study was published Jan. 6 in BMJ.
Even though oral contraceptives are more than 99 percent effective with diligent use, almost 10 percent of women become pregnant within their first year of use. Many more women will stop using oral contraceptives when planning a pregnancy and conceive within a few months. Little is known about the potential health effects to children from in utero exposure to the hormones in oral contraceptives.
While previous studies have primarily relied on women recalling their past oral contraceptive use, Charlton and colleagues were able to tap into a wealth of data collected from multiple Danish health registries between 1997 and 2011 and linked by the unique personal identification number assigned to all Denmark residents. The researchers looked at 880,694 live-born infants, and the health of these children one year later. Oral contraceptive use was estimated based on the date of the mother’s most recently filled prescription.
Among the women in the study population, a fifth had never used oral contraceptives before becoming pregnant, and more than two-thirds had stopped using oral contraceptives at least three months before becoming pregnant. Eight percent had discontinued use within three months of becoming pregnant, and 1 percent, or well over 10,000 women, had used oral contraceptives after becoming pregnant.
The prevalence of birth defects was consistent across each category of oral contraceptive use, and remained so when the researchers added in pregnancies that ended as stillbirths or induced abortions.
Charlton was supported by funds from Harvard Chan School’s Maternal Health Task Force and Department of Epidemiology Rose Traveling Fellowship; the training grant T32HD060454 in reproductive, perinatal, and pediatric epidemiology and award number F32HD084000, both from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health; and the training program in cancer epidemiology under grant T32CA09001 from the National Cancer Institute, National Institutes of Health.
Adapted from a Harvard Chan School news release.
Stay informed via email on the latest news, research, and
media from Harvard Medical School.