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
Hi, I’m 5 days late on my period I took Postinor 2 after having sex with my bf earlier this month and then went for another birth control pills (antibiotics) during the middle of the month I bleed for five days and now I have not seen my period, I ran a home pregnancy test but negative. Is it possible that I’m pregnant?
Hi there Amarachi, the antibiotics might very likely be the reason why your period is delayed.
My period was supoosed to be on 20 of july but up to now i havent. Before that i took antibiotics like Doxcyline and other names of antibiotics i forgot now. And i also did do pregnacy test twice it was negative. Should still worry? Pls help.
Hello Sarah, the antibiotics might be the reason why your period is delayed.
Maureen
I took some antibiotics when I had my periods early this month..I had some slight bleeding and some effects that made me stop taking the antibiotics.I had unprotected sex where he pulled out.. According to my timer..i was supposed to have my periods yesterday but nothing…can the antibiotics cause the delay…
Hello Lilly, yes antibiotics can cause a delay in your period.
I was diagnosed with BV and currently taking metronidazole vaginal suppository for 4days now. This is my first time to exprience delay period. I had unprotected sex july 14 supposedly my fertility period. Is it because of the antibiotic that im taking or possible that i am pregnant?
Hello Maggie, the menstrual delay you are experiencing might be as a result of the antibiotics taken.
I wish I found this article sooner!! I was on a 10 day course of penicillin which delayed my period by 5 days. My period started about 20 hours after I finished the last antibiotic (today). Thanks for the article!
Hello every one my period flow started yesterday, I took ampiclox that evening, today I did not see any flow, what could be the cause?
Hi Sophie, antibiotics can delay a period. If you haven’t gotten it at this point I would recommend taking a test.
I missed my period and I hv run pregnant test and is positive but am on typhoid and malaria medications …what could be problem?
Hello Gift, congratulations, this means you are pregnant.
I would definitely go see your doctor immediately so they can switch you off of the antibiotics. They can be unsafe for pregnancy, unless they have you on a safe one, but if it’s doxycycline it is not safe to continue while pregnant.
I’m 9 days delay now…our last sex intercourse was on June 24, two days after we have sex I got sick and I drink antibiotic named klacid500 and have injected a serum for my throat because i had flu…11th of july is my period date is it possible that I’m pregnant???
Hello Thessa, the antibiotics might be the cause for the delay in your period.
I normally see my monthly fluid by the middle of the month, at the range of 15, 16, 17, and 18, and today is the 19th, though I have been taking ampiclox since the 16th. Is it the ampiclox that’s delaying my monthly fluid?
Hi Tee, yes, the antibiotic can be the cause of the delayed period.
hello, i took ampiclox antibiotic and when my period came,thick like chese heavy uncontrollable blood keep dropping like an abortion and concerned pls what could be the cause? i did not take any pregnancy test though?
Hi Eunice, could have been the effects from the antibiotics as that can affect your period. However I probably would have taken a pregnancy test and determined if it was a miscarriage also.
I had a really bad strep throat so I took penicillin for a month. My period is usually pretty on time but this time I’m already 5 days late. I have taken a birth control pill once for my acne but now I’m no longer taking it. I had a protected sex with my bf (used condom) 2 days before my ovulation date. I stopped taking penicillin 3 days ago since my strep got a bit better. I felt cramps left side on my stomach. Idk if it because I was on antibiotics too long or my period is coming but still no period. Should I worry about pregnancy?
Hi Keke, if you had protected sex, you shouldn’t have to worry about getting pregnant. However antibiotics can delay your period as well. Cramping could have been ovulation cramping too depending on when that fell in your cycle. I would take a pregnancy test if your period is late but again if you were using protection that’s not something that I would necessarily worry about unless that method (condoms) failed.
I stopped menstruating June 12th and I was sick like 10days after… Took drugs (antibiotics) and injection for malaria and typhoid… I dry humped with my boyfriend without clothes on and my period is 7 days late… Can I be pregnant
Hello Oyin, the antibiotics might be the cause for the delay with your period.
I’ve been on Doxycycline, Doxepine &Fluconanazole (generic brand for Diflucan )and my cycle started slow and now it’s gone over 7 days..I completely just stopped taking ALL medication, it’s for a skin bacteria ..this is why I hate taking medication..
Hi Dee, did they recommend you stopping the medications or did you just stop on your own? If so I would discuss with your doctor the ramifications of that. Otherwise, it could be normal for your body to be later than usual. Although I would also take a pregnancy test if there is any chance you could be pregnant.
PLS what can stop or help to control a prolong period????
Hi, it depends. If you naturally have heavier periods and are open to the option of hormonal birth control you can go that route.
I am now 17 days late for my period. I had sex between those days but he pulled out. I took a pt, but it says negative. I am so anxious about this. I was sick 3 weeks ago and took meds and antibitiotics. And now I am more than 2 weeks late for my period. Please help me. Oh yes, my previous period was 2 weeks early than the usual. I am thinkingvthat my became irregular. Is that normal?
HI Anne, the illness and antibiotics can cause a shift in your period. Our bodies are pretty sensitive honestly. If your pregnancy test is negative then you most likely are not pregnant. However if you are not trying to start a family, unless you are regular, the pull out method is one of the least reliable ones and I would recommend a regular form of protection.
My periods normally last 6-7 days. I got my period Sunday and it’s now tuesday night. I haven’t had my period since this afternoon. Can doxycycline shorten a period? Should I be concerned?
Hello Christy, the use of an antibiotic can delay or affect the regular flow of your cycle.