Some of you may have seen this report on TV or scanned through it while reading the paper. It is worth discussing because the concerns lie in not just birth control pills but in any device containing synthetic Progestin, which is different than Progesterone (not synthetic).
This Danish study followed 1.8 million women of childbearing age for more than a decade drawing data from national prescription and cancer registries. During that time, over 11,000 cases of breast cancer were found. The researchers concluded that women using hormones experienced a 20% increase risk of developing breast cancer compared to nonusers. In other words, for every 100,000 women using hormonal birth control, there are 68 cases of breast cancer annual, compared to 55 cases a year among nonusers. The risk also increased with age and varied by formulation. Limitations in the hormonal birth control study include the fact that physical activity, breast feeding and alcohol consumption which can influence breast cancer risk were not accounted for.
The link between birth control pills and breast cancer has always been somewhat controversial. But this is the first study that looked at the risks associated with current low dose birth control pills and devices in a large population. These devices include Progestin implants (Nexplanon) and intrauterine devices (IUD) that release Progestin. The research suggests that the hormone Progestin may be raising breast cancer risk. Thats an important thing to remember because the thought has always been that estrogen causes cancer. And this is not the only time that Progestin has been implicated in the risk of breast cancer.
One of the most popular studies that shed some light on this subject was the 2002 Women’s Health Initiative (WHI) Trial. This study evaluated the use of conventional hormone replacement therapy (HRT) in the form of oral conjugated estrogens and oral medroxyprogesterone acetate (MPA). There was quite a shock over the negative outcomes of this study which included increased cardiovascular and cerebrovascular (stroke) disease, breast cancer, and thromboembolic events (blood clots). We finally dug deeper in the research to find some of the causes.
The first potential cause is the oral ingestion of estrogen. When you take estrogen in a pill form it is presented to the liver in a much more direct concentrated way. The liver synthesizes certain proteins such as clotting factors, sex hormone binding globulin and thyroid-binding globulin. What does that mean?? It means oral estrogen, whether it be a birth control pill or oral HRT stresses the liver and produces inflammatory proteins and more clotting factors. Of course this is dependent on the amount of estrogen consumed. Synthetic hormones also produce unfavorable metabolites that have the potential to change DNA that raises breast cancer risk.
The second issue is progestin (synthetic) vs natural progesterone. There are many studies that indicate that medroxyprogesterone acetate is detrimental to cardiovascular function. A popular study known as the Postmenopausal Estrogen/Progestin intervention (PEPI) trial, found that at the end of 3 years, oral estradiol increased HDL (good cholesterol) by 7%, but this increase was reduced when MPA was added. Oral progestins also under go a substantial first-pass effect on gut and liver metabolism. Is it the progestin metabolites themselves that increase the risk of breast cancer or the fact that progestins turn on estrogen receptor expression that allows more estrogens to be shunted down “bad” pathways?
Women who stayed on these hormones for 10 years or more experienced a 38% increase in their risk for developing breast cancer compared to nonusers. In contrast, there was no increase in breast cancer risk for those using hormones for less than 1 year. That being said, these types of birth control methods in general are safe, effective and accessible options for many women. Perhaps women can change to a different form of non-hormonal birth control, such as an IUD without hormones (Paraguard), condoms or a diaphragm.
Talk to your doctor or practitioner about the pros and cons of different types of contraceptives. A hormonal birth control method may be fine for now, but you may want to reassess its use as you get older or if you have been using a hormonal form for more than 10 years.