By Charlotte Helston
Despite deaths like that of Shuswap woman Rhonda Bergen, the Society of Obstetricians and Gynaeclogists of Canada has ruled the risk of venous throboembolism (VTE) from taking hormonal contraceptives is very low. So low, they say in a new position statement, that pregnant women are at a higher risk of VTE than women taking birth control pills.
Bergen died suddenly after being on Yasmin for just six weeks. An autopsy report confirmed that her birth control pill was partly to blame. Class-action lawsuits in Canada which represent other women who have suffered like fates suggest Bergen's death is far from an isolated incident.
The society acknowledges recent controversy over certain combined oral contraceptives (COCs) like Yaz and Yasmin but believes the reaction has been somewhat overblown.
"Overall, the risk of VTE in combined oral contraceptive users is very low and, for most women, the benefits of this effective form of contraception will outweigh the risks," the society says in a new position statement. "Fear and confusion resulting from media coverage of rare events... has the potential to create far greater harm as inadvertent pregnancies are generally the result of panic stopping of COCs and these pregnancies themselves carry greater risks for VTE. Such adverse effects on public health have been documented in a number of countries following pill scares in the past ."
The society says the death rate due to oral contraceptive use is 1 in 100,000 women per year, "similar to the risk of death from other uncommon causes... falls, drowning, poisoning, domestic violence."
That would be about one death a year for the Vernon area, which has a population of about 97,000.
The risk goes up if a woman is already at risk of VTE, for reasons such as age, obesity, cigarette smoking, or family history. Bergen had two factors already contributing to higher risk: obesity and polycystic ovary syndrome (PCOS) when she was prescribed Yasmin, a Drospirenone-containing contraceptive to counteract her hirsutism, or excessive hair growth.
"Drospirenone-containing COCs are often prescribed for their anti-androgenic effects. Obesity and hyperandrogenemia figure prominently in the phenotype of women with polycystic ovary syndrome (PCOS) and both obesity and PCOS have been linked to increased risk for VTE," the society says.
So while the risk for most women is small, it's somewhat larger for a minority of women. How much more is the unanswered question. Until more is learned, the society has several recommendations for health care providers prescribing birth control to women.
They state that health care providers "should assess risk factors for VTE as one component of identifying the optimal choice of contraception for a given woman" and "understand that the risk of VTE in COC users is highest in the first months of use..."
They also direct providers to educate their patients about the possible risks, and to inform them of signs and symptoms of VTE and what to do if they occur.
Though some studies reviewed by the society suggest fourth generation contraceptives, like Yasmin, create a higher risk of VTE, the society is laying its trust in what it calls "the highest quality evidence available at this time." This evidence states there is no difference in risk between the type of contraceptive used.
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