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
Hello,
I had cephalexin for a urinary tract infection starting on 19th August. I took them for 7 days. Period due on Wednesday 30th August and I had it for 1 day on Thursday 31st and then nothing on Friday 1st. Is this normal for it to effect it this much? Normal period lasts around 4 days but are usually quite light.
Had sex a couple of days before period due around 27th and 29th. If i bled even for just 1 day could i be pregnant?
Thanks
Hello Rachel, antibiotics are known to disrupts a female’s cycle. If you had unprotected sex around the time of which your period was due then you might have conceived. If you have a missed period the next time around please take a pregnancy test 7 days after.
My wife is having a problem during her menstrual cycle after the use of a medical abortion kit 1 year ago. Now the bleeding is low and last only for two to three days as earlier it occurred in a right way for 3 to 5 days. Please help me and prescribe me some medicine.
Hello Surveen, I am sorry there is no medicine I can prescribe to make her menses normal. However please read the link below to get more information on this.
https://womanjunction.com/menstrual-cycle-abortion/
Hi , I am currently dealing with an ear infection. It happened the 30th of August I went that day and picked up over the counter Tylenol for severe sinus and within 2 days I took 12 then stopped those . Then on Sep 2 I was prescribed ibuprofen 800 and I’ve taken about 6 . My cycle came on the 2nd and it ended the 4th ? Is that normal
Hi there Z, the taking of these medications might have interrupted your cycle.
Hi have been taken APo -roxithromycin antibiotics for a ear infection but my period was to come on the 2nd of September 2017 but still nothing will the antibiotics be the cause thanks
Hello Adriana, yes anti-biotics normally cause menstrual delays.
I took acivir 800 , allegra and still taking nurokind gold was suffering from herpes zoster had unprotected sex on 29 july got my periods next day only i am 4 days late for my periods
Hello Shobha, please take pregnancy test 7 days after missed period.
Hi. I had period last of 19 of last month. And then this month I was having fever n farengit tissue so I took antibiotics. And till now I m not getting my period please tell me what may be the reason?
Hi there Subu, the antibiotic might be the reason why your period is delayed.
My boyfriend and I had unprotected sex at least 3 times this month however he never came in me or at all for that matter. And never during my fertile window. I have been on chephlix (or something like that) for 10 days for a recurring case of strep. My cycle is typically 28 days long however last month it was 33 days after being on antibiotics and today is day 34 of this cycle. I have taken one pregnancy test and it came back negative. And I have yet to start my period. Help…
Hi there Kristen, the antibiotics is what might have cause the delay in your period.
Am taking doxyciline, cifran and flagyl for PID my period is delayed seven days i did pregnancy test(blood) its positive but i don’t have any symptoms pls help me
Hi there Hundeyin, if blood test for pregnancy shows positive this means your are pregnant.
I was a week late on my period, went to the doctor was told I may have a uti, but was also told that it was too soon, somehow, for my negative pregnancy test to be accurate. I was prescribed nitrofurantoin for the uti. I took the pill that morning and ended up getting my period later that night. I usually last 3days on, but it’s been nearly 7 days and I’m still not only bleeding but having cramps (which aren’t normal for me at all) on and off.
Hello Ms. J, kindly read the following link with regards to this: https://womanjunction.com/can-a-uti-delay-or-stop-your-period/
Hi I’m On my menstrual cycle now and I currently have to take azithromyocin . Would that affect anything ?
Hello Mariah, antibiotics contribute to the absence or delay of periods.
Hi everyone, I have sex with my boyfriend last month and till now I haven’t seen my period. I tested twice and it shown negative. I really Dont what’s happening
Hello Da silva, please take pregnancy test 7 days after missed period to confirm if you might be pregnant.
Thanks a lot Alison! I did the test and it came out negative and still my period is not yet here.
Hello Da Silva, has it come as yet?
Still nothing Alison … I’m stressed
I am taking doxycycline, secnidazole, candid b cream, diclofenac and injected ceftriaxone and I am late on my period could it be the cause?
Hello Pochi, yes the taking of antibiotics are known to delay the period.
Hi, I took antibiotics for uti during my last menstrual period last month (19-21) I had normal menstrual Symptoms last week and till now nothing what could it be? The effect of the antibiotics?
Hi Sarah, yes taking of anti-biotic could be the cause of your delay.
My period started today and I had unprotected sex with my boyfriend same today and I took ampiclox beecham is there a possibility that I will get pregnant?
Hi there Martha, though the risk is less likely you are not 100% out of the woods.
can penicillin mess up your period
7 days late for my period. Took 2 test that showed negative. A week before i took antibiotics for a uti. Coukd this be the cause for my delay?
Hello Angie, yes the taking of antibiotics is the cause for delay.