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 was put on zithromax and an antibiotic at the start of the month they have just finished now and my period is 11 days late .I am 100% not pregnant so could the lateness be because of the medication ?
Hi there Alanna, yes the delay is as a result of the antibiotic.
Hi. I was expecting my period to come on january 9 onwards. But unfortunately my period was delayed again. Last month i didnt have my period. I also have unprotected sex these past months. I took antibiotics on december 12 which is the day i should have my period. This month, when the week of my period came, i felt the symptoms of having my period, (before january 9 until thursday) but now, the symptoms i felt is gone. Is it still because of the antibiotic i have taken?
Hi there Isabel, the antibiotics is more than likely the cause for the delay.
I was on augmentin (2×10 days) for a double ear infection and it gave me a yeast infection and was put on Diflucan (took 2) about a month later. My period came early and lasted days longer by spotting. Could all of the medication be the cause?
Hello Dee, yes the antibiotics is likely the cause for this.
I have been taking Laclox ampicillin for some months now after intercourse and I noticed my menses has stopped flowing heavily as before. It now comes for probably 2 days and without pain, I did a pregnancy test but it came out negative. What do I do?
Hello Angel, a negative pregnancy test means you are not pregnant to try for pregnancy use the below link to calculate your most fertile days:
https://womanjunction.com/
My wife has pretty regular cycles of 27 days with a few being 31 days. Her last period was December 9. We noticed her fertile mucus on December 21st so we made a note period would be later since usually her mucus gets fertile around day 9 versus day 13. Well, on December 26th she took a zpack of antibiotics for severe case of flu for 5 days. On day 25 of cycle which was January 2nd we had unprotected sex. Today is day 31 and still waiting. She has had 31 day cycles in past but not many. We recognized the fertile mucus was later this time before she got sick however I would think that day 25 would have been a safe sex day. Do you we are safe from pregnancy and could antibiotic delayed ovulation when she started the ovulation process on December 21st?
Hello Ben, yes the antibiotic might have caused a delay.
I had sex on d 1st,2nd & 3rd of january and I used ampiclox for the 1st 2 days and I am supposed to see my period on d 7th of january, which I am yet to see. Could my period be delayed because of the antibiotic I used?
Hello Tabitha, yes your period could have been delayed due to the antibiotic used.
Hi, I had sex on 11th Nov after that I started ovulating then few days later felt all my period symptoms (cramping).I later had to use antibiotics 2 days to my period.. Now am 7 days late and still have cramps
Hello Deb, the antibiotics is likely the reason for the delay.
I started my periods on 9 dec 2017 and it ended on 15, on 24 dec I had sex but there was no penetration, on 1 jan 2018 I was put on tonsillitis injection up to now I haven’t seen my periods again yet there are no signs and my vagina is itchy and dry, what could be the problem?
Hello Eunice, the tonsilitis injection which is more than likely an antibiotic is the reason for the delay in your period.
I took ampiclox today and my period is already a day late although i took ampiclox sometime last month cause am on medication, after reading this post, am scared will my period be delayed further?
Hi Mhiz. It’s quite possible that your period could be delayed a bit. If you are having unprotected sex you should also consider the possibility of pregnancy as well if you are on oral birth control.
My last period was Nov. 21, 2017 and had sex last Dec. 7, 2017. I still dont have my period. But my boyfriend didnt even cum. Is there a possible that I’m pregnant?
Hi Lineil. Have you taken a pregnancy test? Anytime you have unprotected intercourse during your fertile period you can get pregnant. Pre-ejacualtion still contains sperm and can result in a pregnancy. It would be smart to take a test.
Can antibiotics delay the period as much as two month, three or even more?? I finished taking doxycycline monohydrate in October 30 pills 100mg for acne. My last period was October 17 and now we are in January. Going on 3 month now! Is that normal? I am very scared. No pregnancy. I have also been on B12 shots but that is it.
Thanks!
Hi Lana. If you were on 30 pills it can most certainly affect the regularity of your period. ALso if you have been having unprotected sex you could have gotten pregnant as it generally makes oral birth control useless. I would recommend a pregnancy test (if there is a possibility that you could be) and also make an appointment with your doctor.
I had sex on 3rd December, the day after the last day of my periods. I took augmemtin 625mg twice a day for 5days from 11th December as dental medication. I’m supposed to have my periods on 29th December and it is two days delayed. I’m stressed out whether I’m pregnant or due to medication. I did Beta HCG blood test and it is negative.. Please advice..
Hello Rangani, this delay might be as a result of the antibiotics taken.
I took penicillin and my last period was in early Dec could that be the delay if so how long does it take to come back
Hello Gianna, yes the taking of the Pencillin is more than likely the cause for your delayed period.
My obgyn doctor prescribed me ciprofloxacin for infection, so my period supposed to come 3 days ago it never came did u think this antibiotics can stop it.
Hello Tasheena, the antibiotics did not stop your period, rather, it delayed it. Your period will return naturally soon.
Please I took erythromycin at the end of my period last month Nov, and now my period has been delayed for 4 days and still no sign. But I’m not pregnant since I’m a virgin… I really wish to have my periods soon. Is there any medication or way out to reverse the impact of the antibiotic?
Hi there Prilly, your best option is to wait for your period return naturally. It will.
I had sex on December 8th and my period was suppose to start yesterday and I haven’t started. But I took cephalexian 500mg (might not have spelled it right) for a UTI could that have messed up my period? I took two pregnancy tests and they appeared negative.
Hello Kaylee, yes the antibiotics is more than likely the cause for your delayed period.