Antibiotics. We’ve all taken them at some point (or at many points) in our lives, but do we have any idea of their effect on our bodies and our hormones?
When antibiotics are prescribed and taken, they can have an impact on your menstrual cycle, even if they were not prescribed specifically for an infection of the reproductive system. i.e urinary tract infections, bacterial infections and some yeast infections. (I still can’t understand why antibiotics would be prescribed for a yeast infection, when yeast infections are one of the main side effects of antibiotic usage!) :-/
The mechanism for how antibiotics affect your period lies in the fact that they make estrogen (a primary female sex hormone), less available to the body for proper menstrual cycle function.
Antibiotics can affect regular menstrual cycle functioning in two ways:
First, most antibiotics are metabolized by the liver, the same place that estrogen (and progesterone) are metabolized. When antibiotics are present, it can change the speed at which estrogen is metabolized, and reduce the available estrogen in the blood stream. This can cause problems for many women because we need estrogen in our follicular phase to stimulate the ovaries (to produce an egg) and to thicken the endometrium. If there is a lack of estrogen, this can cause either delayed ovulation or cause an anovulatory cycle (which is a cycle in which a woman does not ovulate).
When ovulation is delayed or it doesn’t happen at all, this can throw off the regularity of your menstrual cycle.
Second, antibiotics have an impact on healthy gut bacteria – they will kill the bad bacteria but they’ll take down the good ones too unfortunately. The theory is, these good bacteria convert the broken down estrogen back into active estrogens which is then reabsorbed into the blood stream (aka entero-hepatic circulation). If these bacteria are killed off, those estrogens never actually get back into your blood stream.
Additionally, many antibiotics cause diarrhea which in turn increases excretion of estrogen from the body. FYI: once estrogen is processed by the liver, it is then moved to the digestive tract and is either reabsorbed or excreted.
If estrogen is excreted too fast from the body, levels drop and in turn, affect your cycle.
The thing is, when estrogen levels change in the blood, it affects your pituitary gland function. The pituitary gland secretes FSH and LH (the hormones that stimulate your ovaries to build and release an egg) based on the level of estrogen in your blood. If your estrogen is too low, your brain gets the signal and doesn’t produce as much FSH and LH, which will totally mess with your body’s ability to ovulate when it’s supposed to.
PS. this applies to birth control pills too. Antibiotics can decrease the effectiveness of your BC, so always use a backup birth control option like condoms during the time you are taking antibiotics if you absolutely have to take them.
Keep in mind, studies done on this subject have all been inconclusive but I’ve had this experience on numerous occasions and many women have described similar stories.
It’s also helpful to keep in mind that when you’re sick you might experience a delay in ovulation and subsequently a delayed period. This goes for acute periods of stress. Your body basically considers these times unsafe, so you might not release an egg. I know it seems counter-intuitive, like why the hell is my body not working, but it’s actually doing exactly what it’s supposed to do. That is, not having a baby when there is potential danger.
If you simply MUST take antibiotics, I recommend chowing down on lots of fermented foods like sauerkraut, kim-chi and kefir.
You should also take a good probiotic for at least a month after you’ve taken the antibiotics.