Women who use birth control pills are at greater risk for developing blood clots during the first six months of oral contraceptive use, and they are at even greater risk when first starting the pill and when restarting the same pill or a different pill after a four-week or greater break.
The interim data comes from a large, prospective, observational cohort safety study on the increased risk of venous thromboembolism (VTE), or blood clots, in women who use birth control pills. The study was funded by Bayer HealthCare Pharmaceuticals Inc., makers of Yaz, one of the most popular brands of birth control pills.
Blood clots are a potential side effect for women who use combination birth control pills. But Bayer’s Yaz and its sister pill, Yasmin, have come under fire in recent years for advertisements that the Food and Drug Administration (FDA) said overstated the drug’s benefits and downplayed its risks.
Those criticisms were compounded when the pharmaceutical company was later hit by thousands of lawsuits from women or their family members who claimed that Yaz and Yasmin put them at even greater risk for serious health problems including blood clots, heart attacks, strokes, gallbladder damage, and even death. The lawsuits claim Bayer never fully warned women that using Yaz and Yasmin could potentially kill them.
Bayer has been quick to dismiss the charges against it, arguing that Yaz and Yasmin are no more dangerous than other birth control pills, calling blood clots a “well-established risk in women who use combination oral contraceptives (COCs).’” Bayer says it was important for the company to take a lead in the studying and communicating of the risks and benefits of combination birth control pills.
“The new information is helpful because while healthcare providers have long known about the risk of VTE associated with COCs, there was little information to indicate that there was an increased risk in women restarting COCs after a four week or greater period of non-use. This new information should provide both healthcare providers and women who choose a COC for contraception with additional information when making the decision to implement a pause in their COC routine,” said Leo Plouffe, MD, Vice President, US Medical Affairs, Women’s Healthcare, Bayer HealthCare Pharmaceuticals.