There are many birth control options today and understanding how the various methods work can help you choose a method that is most comfortable for you. The most commonly used method in younger women is birth control pills. The options in this category that all function based on the same principles are birth control pills, the birth control ring, Nuvaring, and the birth control patch, Ortho Evra. Each of these medications contains varying amounts of synthetic estrogen and progesterone hormones with the exception of one pill, the “mini pill”, which contains synthetic progesterone only.
How Hormonal Birth Control Works
There are several ways that these medications work with the primary effect being to prevent the release of an egg from the ovary – a process known as ovulation. Additional effects of these medications that add to their effectiveness is thickening of the cervical mucous to prevent sperm from entering the uterus and thinning the endometrium which is the lining of the uterus in which a fertilized egg implants. The thin endometrium makes it difficult for a fertilized egg to implant and grow in this tissue layer. This is essentially the final backup safety measure just in case an egg and sperm ever do have an opportunity to meet up while a woman is using one of these methods.
Synthetic Estrogens and Progesterones
The actual methods by which these medications work are incredibly interesting. What the synthetic estrogens and progesterones primarily do is they affect the release of a hormone called gonadotropin-releasing hormone (gnRH) from an area of the brain called the hypothalamus. This hormone normally tells a different area of the brain, called the pituitary gland, to produce hormones called FSH and LH which travel through the blood stream to communicate with the ovary and tell it when to begin maturing an egg and when to release that egg. When the synthetic estrogens and progesterones are present in the body’s blood stream, they prevent the release of gonadotropin-releasing hormone from the hypothalamus. This then prevents the proper release of LH and FSH from the pituitary gland so that the ovaries don’t receive the chemical instructions as to when and how to mature an egg. The end result is the prevention of ovulation. And, as I am sure you can conclude, if no egg is released, no pregnancy can occur. Because the “mini pill” does not contain any estrogen, it does not reliably prevent ovulation like the methods that have both hormones in them.
The other pregnancy-preventing effects of these methods are due to the synthetic progesterones and these effects are what make the “mini pill” function. What they do is they make the cervical mucous very thick and tenacious so that sperm can’t pass through the cervical canal into the uterus and they also thin the endometrium significantly so that if an egg is ever released and fertilized, it would be very difficult for it to implant and grow in this environment.
Now, let’s review a little more specific information about each of these birth control options.
Birth Control Pills
The birth control pills are extremely convenient because they are administered orally. In order for them to be maximally effective, they must be taken every day at about the same time of the day. If they are taken too far apart or if a day is missed, the failure rate begins to increase. This is an extremely popular method, but for some women it is difficult to remember to take a pill every day. Therefore, different methods of delivering these hormones into the body have been developed to enhance compliance. These newer methods are the birth control patch, Ortho Evra, and the birth control ring, Nuvaring.
Birth Control Patch
The patch allows for the absorption of the hormones through the skin and is changed once weekly for three weeks and then is left off for a week which is when the menstrual cycle will occur. For many women, this is a more desirable method because it does not require the daily thought process of having to take the pill. In order for this method to work reliably, the patch must completely adhere to the skin for the entire week. Fortunately, patch detachment is rather rare occurring in 5% or fewer of patients. So, it works very reliably for the majority of women who use it.
Nuvaring for Birth Control
The Nuvaring method allows for the absorption of the hormones through the vagina from a soft, flexible ring that it is left in the vagina for three weeks after it has been placed. There are several common misconceptions that I hear from my patients about the ring. The first is that some think that the ring may travel throughout their bodies. This can’t happen because the vagina is a closed environment with the cervix occupying the top. So, it’s impossible for it to go anywhere but out which is very rare. If the ring does fall out, it is simply washed with warm water and reinserted. This brings up another common misconception – that it has to be in place during intercourse. It actually does not have to be in the vagina during intercourse, so if it falls out, its effects will not stop working as long it is replaced within 6 hours.
Birth Control Effectiveness
All of these hormonal-based birth control methods are ingenious and highly effective approaches to preventing pregnancy, however, in order for them to work, they must be used correctly or else there is a risk of failure.
Each of these methods have similar failure rates. Theoretically, with perfect use, only about 3 women per thousand should get pregnant per year while using these methods. However, in real life, approximately 8-9 women per hundred get pregnant per year while using them. Why is there such a huge discrepancy between the expected failure rate and the real failure rate? Well, there are a lot of reasons that account for this discrepancy and they primarily boil down to human failure. These reasons include forgetting to take the pill at the same time daily, forgetting pills altogether, starting the method too late in the menstrual cycle, taking medicines that interfere with the absorption of the pills or medicines that make your body metabolize the hormones too rapidly. Other issues leading to failure include not recognizing the patch peeling off of the skin prematurely or having the ring fall out of the vagina and not replacing it quickly enough. So, in general, it’s not the medication that is failing the patient, it’s the patient that is failing the medication.
If you are interested in using one of these reliable and popular methods of birth control, please discuss this with Dr. McDyer or Dr. Suhrer so that we can help you determine if one of these methods is a good choice for you.