Bayer HealthCare Pharmaceuticals announced interim results from a large, prospective, observational cohort safety study that offer insights into the increased risk of venous thromboembolism (VTE), or blood clots, which is a well-established risk in women who use combination oral contraceptives (COCs), also known as “the pill.”

Specifically, the new data provides healthcare providers with information regarding when the VTE risk associated with COCs is highest.  The risk of VTE is highest during the first year of COC use and the new data suggest that this increased risk is greatest during the first six months.  This risk is greatest when first starting “the pill” and when restarting the same or a different “pill” after a four-week or greater break.

The new data are from the ongoing, Long-Term Active Surveillance Study for Oral Contraceptives (LASS)—a large, multinational, prospective-cohort, five-year follow-up safety study to the European Active Surveillance (EURAS) study.  Cardiovascular events, including VTE, were the main clinical outcomes studied in LASS. Together, these two studies will provide data for up to 10 years on women using various COCs.