Did you know that antibiotics could affect the menstrual cycle? Indeed, most of them can have an effect on menstrual periods, with some reporting delays. Find out more about the connections between antibiotics and the menstrual cycle below.
Your Regular Cycle
During the first 14 days of a 28-day menstrual cycle, your follicle will start to grow and kick-start the initial production of additional estrogen. It will start to make the endometrium lining thicker. When ovulation commences, the estrogen hormone will be joined by the progesterone hormone from the corpus luteum to make the endometrium mature and thicker.
How Antibiotics Affect the Normal Cycle
Antibiotics can interfere with your body’s mechanism, which secretes the human chorionic gonadotrophin hormone (hCG) and cause uterus shedding to delay your period. This will happen mainly because the available estrogen will be reduced to cause a change in your cycle for it to become irregular.
A study done in 1947 shows that Penicillin caused heavier bleeding, changes in pain and PMS symptoms and the start of the cycle itself, but they stated that they weren’t able to find any correlative information regarding that.
There are actually two ways antibiotics could affect the estrogen metabolism. Most antibiotics are metabolized in the liver, and when they are present, the metabolism rate of estrogen as well as progesterone will be affected. This can interfere with the estrogen supply that is in the blood and causes an irregularity of the menstrual cycle.
In order for the follicular phase of menstruation to occur, the estrogen is needed to stimulate the ovaries and thicken the uterine wall. Without this, ovulation doesn’t happen or it happens late, which obviously affects when your period will arrive.
Other Issues with Antibiotics
There are some antibiotics that will cause diarrhea-like symptoms when they interfere with the stomach flora.
Even though it’s supposed to kill the bad bacteria in the body, it also affects and kills the good bacteria as well, which is why some women report yeast infections as well after their use of antibiotics.
The entero-hepatic circulation will be affected and cause a reduction of estrogen levels in the blood. It’s becausegut bacteria that usually re-activates small amount of estrogen in intestine are no longer available [1].
When the estrogen levels change in the blood, your cycle will be affected low estrogen levels fail to stimulate pituitary release of hormones. Your body actually ovulates based on the pituitary gland’s ability to identify that sufficient estrogen is in the blood, and then cause LH surge which causes ovulation on 14th day of cycle. So antibiotic treatment can affect these delicate hormonal balances.
So your body doesn’t have enough estrogen to regulate normal menstrual cycle.
Another important point to note is that antibiotics change your body’s metabolic performance and the ability to sustain a steady hormone level.
Use the Second Form of Protection if you are Not Trying to Get Pregnant
Antibiotics can also affect the estrogen as well as progestin levels in oral contraceptive pills. Estrogen is actually an active ingredient in these pills and the antibiotics will affect how it’s metabolized in the body.
Rifampicin and Rifabutin are liver enzyme-inducing drugs and can clear the estrogens from blood at faster rate thereby reducing the contraceptive benefit anticipated from contraceptive pills.
You should get medical advice if you are taking antibiotics in the first seven days of a new pill packet and you engage in sexual intercourse in the last five to seven days. The antibiotics could disrupt the normal protection that the pills provide and cause you to get pregnant.
So if you are taking antibiotics, ensure that you are also protecting yourself as well if you are not looking to have another child right now.
Reasons other than antibiotics that affect your period
While antibiotics get a bad rap regarding the effect on the body and the menstrual cycle, there can be other potential issues and situations that can go on with the body during the time frame. When sick, antibiotics or not, the body is being stressed to the max.
It is trying to accommodate for being sick and the stress of still having to maintain a home, a job, children, a spouse (because you know, moms don’t take sick days). So take into consideration that it can be affected by the meds or by stress, weight loss or gain, usage of birth control, and PCOS or thyroid conditions.
How to Prevent Antibiotic Related Period Issues
One way to help balance your hormones while you are on antibiotics could be to switch up your diet while you are taking antibiotics (and after as well if you are looking to maintain a healthy balance).
In order to balance the estrogen levels, you can add some fish oil, vitamin D, and vitamin B to your diet as well as probiotics, which can help balance that gut bacteria in a beneficial way.
Plus you’ll want to get enough sleep (which helps so many bodily systems) and be stress free (see above).
In general, antibiotics can affect so many bodily systems. Know that they shouldn’t be something that you take on a regular basis because it can cause antibiotic resistance in the body.
Take them only if necessary and ensure that you take the proper precautions for preventing pregnancy and keeping your other systems in balance.
If your period is still late, however, take a test and be confident with the results. But if you are still concerned with what is going on, be sure to talk to your doctor if you need more information on the effects of antibiotics and menstrual cycle.
References
- Estrogen-gut microbiome axis: Physiological and clinical implications. https://www.ncbi.nlm.nih.gov/pubmed/28778332
I see my period on the 5th of November and last for 5 days when will my ovulation be.
Hello Jessica, click the link below https://womanjunction.com/
Hello, I started taking 875 mg of amoxicillin twice a day on Oct 5th about 2 days after my period ended. And took them for 7 days. I’m not on oral contraceptives. And I had sex near the middle of the month. I still haven’t had my period. I’m bloated and crampy and appear to be ovulating. Could the delay in my period be from the meds a month ago, or should I take a pregnancy test?
Hi there Betsy, the antibiotic could be the cause for delay.
Hi so I am really confused I had my period on the 14 October so it went on for 7 days and stopped had sex and used emergency contraception 8 days went passed and is started again 29 October till 4 November stopped for the day and just started again I had a throat infection and went to the doctor on the 2 November he gave me a shot of antibiotics and 6 days oral antibiotics can it also be affecting my cycle or is it more serious ?
Hello Ashley, both the use of the emergency contraception and the anti-biotics could be what’s currently affecting your cycle.
Hi There.. I took anti-biotic last 4th of oct. for UTI a week before I started my period…I had sex with my bf 27th of sept. We used withdrawal method as a protection. It is possible that I’m pregnant? because until now my period has not come yet… It is because the anti-biotic?? The anti-biotic I took was 500mg 2 times a day every 12 hours.
Hello Jay an, this is quite likely as a result of the antibiotic.
I used Azithromycin 625mg (3x/day) from september 25-30 which I have my period on that time & october 16-20. Why is that I dont have my period last october in which my expected date is every last week of the month. Is this natural side effect of the drug?
Hello ChuChay, the antibiotic might have been the reason for this.
Hi, I had sex on 17 sep and I also got my periods on 22 sep.. after then I receive antibiotic azithromycin for 12 days.. and I had no sex in between.. my periods was supposed to come on 22.. but still 31 I got no periods.. pregnancy test was negative.. but after one day same test kit was showing minutely faded line in test portion.. Am I pregnant or not?
Hello Jiya, pregnancy tests are suppose to be read within first 2-5 minutes of taking them. The antibiotics might have been the reason for your delay. However to be absolutely sure, please retest for pregnancy.
Hi,I am on 5 days Cipro antibiotics and I am trying to conceive. Can this antibiotic affect my chances of conceiving? Thanks.
Hi there Mariah, please see link below to read more on this.
https://womanjunction.com/antibiotics-increase-risk-miscarriage/
Hi, I last had sex on the 28 sept. Then around the 2nd Oct I fell ill due to tonsillitis. I was on antibiotics along with other medication for about 8 days. My period was supposed to start last week but now I’m 8 days late. I haven’t taken a test yet. Could it be the medication or could I be pregnant? I’ve also been having my usual and very extreme period cramps and back aches for the past 2 weeks. Please help.
Hi there Annie, this is most likely as a result of the anitbiotics.
Hi, not sure if anyone will see this but worth a shot. I have read that antibiotics can affect your menstrual cycle a little. But my question is, how long could it affect? I was taking two different antibiotics (amoxicillin and clindamycin) at the same time for 2 almost 3 weeks, as well as Tylenol with codeine, for an abscess in my breast. I noticed that during August (beginning when I found the abscess) my period was late. Was definitely not having sex due to my huge lumpy boob (haha) and then in September, no sex still, my period was late again. It’s now the end of October (I am well, boob is better and have been having sex) and my period is still late. I noticed that it was late by about 3 or 4 days the last two months.
How long is my period going to be affected by medication? Should it be affected this much? Or is my cycle trying to straighten itself out?
Thanks all!
Hello Liv, antibiotics do not affect your cycle permanently so it should be and should have been back to normal already.
Comment Text*on 25th I have unprotected sex then take antibiotics, am on a 26 days cycle, on 26th morning my period was spotting but afternoon still no blood. am I pregnant or it’s the effect of the antibiotics?
Hello Gift, take a pregnancy test 7 days post missed period to confirm pregnancy.
I was prescribed cefdinir 300mg every 12 hrs for 10 days & methylprednisolone 4mg dosepk for throat infection. Now I find that my periods is not here yet. I’m 48 yrs & it’s always been quite regular. The last period was on September 9th. I’m worried. Also, I know for sure that I’m not pregnant. Please let me know your thoughts.
Hello Ann, the anti-biotics is the reason for your delayed periods.
I took post pill on the second day of my taking antibiotics and my period just started like a week before its supposed date. Could it be the effect of the anti-biotics
Hi there Laura, this could be as a result of the morning after pill.
Question
If I had sex on the 10th of September and took some antibiotics for a uti on or around the 25th then got my period on the 1st of September can I still be pregnant?
Hello Tia, the dates for your question does not match up.
Hi, I got an antibiotic shot the day my period was suppose to start. And took a weeks course of oral antibiotics after for an infected umbilical cord hernia. I understand entirely that antibiotics can affect the menstrual cycle. Is this still true if you take the antibiotic the day period is due? I’m pretty sure it was a strong antibiotic shot. I’m 7 days late with a 41 day cycle. I’m normally 28 to 32 day cycle. Thanks
Hi Natasha, this might be due to the anti-biotics.
I took postinor with ampiclux, now am 3days gone. Have done pregnancy test all negative. Could it be cause of the beecham.
Hi there Gladys, anti-biotics have been known to delay periods, so this might be what has caused your period to not come just yet.
I took 2pills of amoxicillin 3times A day for a week to treat chicken pox. Actually stopped taking it on the day my ovulation was supposed to start but now my period is 7days late. Actually had unprotected sex twice but took an emergency contraception pill. Could the delay in my period be due to the antibiotics?
Hello Kimberly, yes, this delay could be due to the anti-biotics.
Check your status First. Anti-biotic can have effect when it is use more than five days. Just buy strip test to know ur results