Thomas Kimble, MD, provides an overview of currently available hormonal contraceptive options.
Jenna Beckham, MD, MSPH, FACOG: Let’s talk about choosing different contraceptives. I know we've talked about sort of the approach to counseling. But let's talk about sort of hormonal contraceptives, estrogen-progesterone methods that are currently available in a lot of our contraceptive options. So just in general, how would you talk about the safety of these different sort of hormones and use in contraception?
Thomas Kimble, MD: One thing is overall hormonal birth control is extremely safe. And I just want to start with that. There are people who shouldn't get certain types, but it is extremely safe. I'm a history buff when it comes to birth control. The first pill that was available Enovid was introduced in 1957. That was introduced by Searle and Pincus, was the person that kind of came up with it. And Enovid was 150 micrograms of mestranol, was the estrogen in it. And then it was 10 milligrams of norethynodrel, was the progestin. We have come a long way.
Jenna Beckham, MD, MSPH, FACOG: It's alarming to even think about doses like that.
Thomas Kimble, MD: I tell you. And it was approved in 1960 for use as a contraceptive. Before that for the 3 years in 1957, its use was and I'm putting up quotation marks, was for menstrual cycle control until we could get it through the FDA. But there were some studies in Europe and there was a big Swedish study where they started getting some hits, some case reports of there were a higher incidence of thromboembolic events in women. And they looked at this closer, more and more case reports came in, and this started around 1965 to 1970. And in Sweden, they looked at this and they found out, well, it was more likely in women who were using hormonal birth control. And then they linked it to the estrogen that was in it., and that really led to the decrease in the types of estrogens as well. Mestranol was the first that was developed, that was a derivation of estradiol, which is the natural form of estrogen, but estradiol has low bioavailability. It's just not absorbed well and doesn't work well, so they changed it, added a methyl group, made it mestranol, further changed mestranol to another estrogen, ethinyl estradiol. Now those of us who prescribe, or control are very familiar with that. That is the estrogen that's used in over 99% of birth control pills and in other forms including vaginal rings and patches as well. That was the estrogen that's been around for decades, and it does have some risks because it is a synthetic form. There are some other estrogens out there that are available now, so that's one thing I look at first when I'm going to prescribe it as far as risk factors.
Jenna Beckham, MD, MSPH, FACOG: Then talking about estrogen as you said, I agree it's important that we remember that birth control is generally- hormonal birth control is generally safe but there are some patients as you alluded to that may have certain medical conditions where estrogen is really contraindicated. What are some of those patient scenarios where you would really recommend avoidance of a combination pill or other method with estrogen?
Thomas Kimble, MD: We typically avoid estrogen in one, women who are postpartum and who are breastfeeding but also women who have risk factors for thromboembolic events. Remember they linked that higher risk in Sweden back to the high doses of estrogen. Women who are just postpartum, it is recommended to avoid it 3 weeks postpartum. Other risk factors include other cardiovascular risk factors. You must be careful with hypertension, people who have a history of thromboembolic events like blood clots in the legs or pulmonary embolisms, a history of a stroke or CVA or high risk for those. For example, people who have complicated migraines, women who smoke, that is another high-risk factor and it varies on age and on the number of cigarettes that are consumed per day but overall it's still a risk factor. Higher BMIs, that's also a relative contraindication for estrogen and people with those risks are people who we would typically start looking at progestin only forms or various methods of contraception.
Jenna Beckham, MD, MSPH, FACOG: As you said there are some conditions where estrogen is risky but there are still some nuances like you alluded to sort of with the smoking depending on the age and how many cigarettes or other tobacco products or nicotine products. I need to remember to talk about vaping and other things other than traditional cigarettes these days and then the patients who've had a prior VTE. Sometimes there are some circumstances sort of depending on what's surrounding it, obviously if they got it while they were on birth control, on estrogen but some other maybe more provoked things related to surgery or immobilization. Sometimes you talk to their hematologist, and they feel comfortable putting them on estrogen but always a little bit more of a nuanced conversation.
Transcript edited for clarity