Birth control is safe, with low risk of clots, for women with sickle cell: Review
Progesterone-only contraceptives may potentially reduce painful episodes
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Hormonal contraceptives — birth control medications that use lab-made versions of reproductive hormones — appear to be generally safe for use by women with sickle cell disease (SCD), a new review study found.
The frequency of thrombosis, or the blockage of blood flow due to a clot, was low to none among women using hormonal birth control, according to the researchers, who reviewed four newer studies and several older ones to determine the outcomes seen with the use of these medications among female patients with SCD.
Further, the risk of painful episodes was generally not increased among those taking hormonal contraceptives, the studies showed.
In fact, the researchers noted, some studies suggested that using contraceptive methods that contain only a lab-made version of the progesterone hormone may decrease painful episodes. Those findings emphasize the need for future studies to confirm any beneficial effects, the team noted.
Overall, “the certainty of evidence was low for all outcomes,” the researchers wrote, adding that “establishing safe practices for hormonal contraception use that account for dynamic health risks is critical for meeting the sexual and reproductive health needs of women with SCD.”
The study, “Safety of hormonal contraception among women with sickle cell disease: An updated systematic review,” was published in the journal Contraception.
SCD is caused by the production of a faulty version of hemoglobin, the oxygen-carrying protein in red blood cells. This faulty hemoglobin causes red blood cells to acquire a sickle-like shape, making them more prone to destruction and to forming clumps that block blood flow in small vessels, thereby reducing oxygen delivery to tissues.
People with SCD are generally at high risk for blood clots
People with SCD are at a high risk of so-called thrombotic events, which are the clinical manifestations that arise from a thrombosis. These include stroke and venous thromboembolism (VTE), when blood clots form in deep veins and can be stuck in the legs or travel to the lungs.
“While the absolute risk of thrombosis is relatively small with hormonal contraceptive use in the general population, there is concern that risk of thrombosis may be further elevated in women with [thrombosis-increasing] conditions and characteristics who use certain hormonal contraceptives,” the researchers wrote. The team added that other coexisting conditions related to sickle cell “may be influenced by hormonal contraception [and] include painful episodes and adverse bone health outcomes.”
In this study, a team of researchers in the U.S. set out to update a previous systematic review on adverse health outcomes associated with the use of hormonal contraceptives by women with SCD.
The new analysis involved nine studies, four of which were new relative to the previous review. The studies focused on thrombotic events, painful episodes, and bone health among women with SCD who were or were not using hormonal contraceptives.
Three studies examined the risk of thrombotic events. One reported VTE in two of 67 women (2.9%) taking combined oral contraceptives, which includes the hormones estrogen and progestin (a lab-made version of the progesterone hormone). Another study found no VTE events among 20 young women with SCD taking hormonal contraceptives.
The remaining study focused on stroke risk and found that oral contraceptive users had nearly twice the risk of any type of stroke and more than three times the risk of ischemic stroke — when there is brain cell death due to low oxygen — compared with nonusers. However, these results were not statistically significant, meaning they could be due to random chance.
“Despite this limited evidence, it is important to consider the well-established high risk of stroke and venous thrombosis among patients with SCD,” the team wrote.
‘Very low’ evidence of poor outcomes with birth control
Six studies on painful episodes, two of them new, generally found that women with SCD taking hormonal contraceptives did not report increases in these events. One study reported that four of 67 women with SCD taking combined oral contraceptives reported an increase in painful episodes. However, this was not reported by the 84 women taking other hormonal contraceptives.
The findings that some progestin-only methods may have positive effects on decreasing painful episodes [suggest] that additional research on medical benefits of hormonal contraception among women with sickle cell disease may be warranted.
In some studies, the use of progestin-only methods appeared to decrease painful episodes and bone pain, but not vaso-occlusive crisis (VOCs). VOCs occur when blood flow to tissues becomes blocked to the point that they become deprived of oxygen, triggering an inflammatory response that results in substantial pain.
“The findings that some progestin-only methods may have positive effects on decreasing painful episodes [suggest] that additional research on medical benefits of hormonal contraception among women with sickle cell disease may be warranted,” the researchers wrote.
Two studies evaluated bone health outcomes. One found no differences in bone mineral density, which serves as an indicator of bone strength and fracture risk, between hormonal contraceptive users and nonusers. The other study reported no diagnoses of osteopenia, or lower-than-normal bone density, among 20 women with SCD using hormonal contraceptives.
Altogether, “the certainty of evidence for all outcomes was determined to be very low,” the researchers wrote, adding that “evidence remains limited for adverse health outcomes, especially thrombosis, with [hormonal contraceptives] use among women with SCD.”
