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 had my wisdom teeth removed back on April 24th, and I was on amoxicillin for roughly about a week, shortly after I was sexually active with my spouse and Im now 24 days late for my period. I’ve taken 2 pregnancy test and both came out negative. I just want to know if I should be worried or not.. My schedule has also changed dramatically.. I was getting up every morning at 6:30 going to school, then work and now I’m out of school so I sleep till about 9ish every morning and work different shifts pretty often.. I’m curious if it’s stress, the antibiotics, or am I pregnant.. I haven’t had many symptoms.. Only when I get into my head about it.. I just need an opinion please.
Hi Cait, you seem to have a lot going on. Antibiotics definitely can affect the efficiency of your birth control if you were on any. Stress and your change in schedule can also affect your period. Our bodies are strong but they can be sensitive as well. I would recommend trying to get some sort of routine and a way to distress as well. If you don’t get a positive or your period, I would however make an appointment with your doctor just to ensure that everything is normal.
Hi I had too an abortion pill and the bleeding has stopped but I see some discharge like brownish bloodish slimy discharge but it doesn’t have a foul odor I was wondering if maybe and ampiclox Beecham could remove such discharge or if there is anything I can do to get rid of it
Hello Zino, this seems to be a natural process, let it be.
Hi I’m 3 days late and haven’t got my period .. I’ve had sex and also had a urine infection and had antibiotics could I be pregnant or am I not
Hello Joanne, the antibiotics might be the cause of this delay in your period returning.
I had protected sex on Apr 16-17. My period came right on time the following month (May 9-13 to be exact). It was accompanied by a cough that leads up to this day. I had to take Augmentin for 10 days. My period hasn’t shown yet this month. I was due on June 6. Should I be worried?
HI Mae, it could be the antibiotics that could delay ovulation and your period, or if you had unprotected sex during that time and are using birth control you may become pregnant. Antibiotics reduce the effectiveness of birth control. I would take a pregnancy test.
Hello. Thank you for the response. Sorry, typo — I had UNPROTECTED SEX during that time (Apr 16-17). We are very certain the intercourse was safe since my partner pulled out minutes before ejaculating. I’m just worried because I had my period ON TIME a month after it happened. Now, six days have passed yet my period hasn’t come up yet for the month of June.
Hello mae, if you think you are pregnant, then you should take a pregnancy test 7 days after a missed period.
Hi. I just wanted to leave an update. Today marks Day 10 from the day my period was due and guess what? It just came in today!!! I’m so happy. I guess the antibiotics had something to do with it. I hope you gals figure it out. Have a great day!!!!
great to hear that Mae!
Hello I had sex three days before menstruation whiles taken antibiotics and since then I have been menstruating for more than two weeks. What might be the cause
Hi Eunice, taking antibiotics can affect your period. It shouldn’t have lasted this long but if it does continue I would recommend calling your doctor.
I had unprotected sex 3days to my menstruation I took postinor2 d next day, my period came out d next day den I fell sick, took lots of antibiotics. Now my period is due for dis month with 3days delay. What’s going on I really don’t want 2 get pregnant.
Hello Linda, the delay in your period might be as a result of the antibiotics.
Hello.. Am really worried I saw my last period on the 12th of March ever since then I have not seen my period till date I ran a blood and urine pregnancy test and it came out negative… Although I have been taking some Anti biotic and virginal inserter like Klin Fast. And am currently on a drug premolim N.. What do I do should I stop stop the medication am really worried cos it’s getting to 3 months now
Hello Gemma, the use of the antibiotics might be the reason for this.
After taking antibiotics my periods started before it’s normal 28 days cycle. Should I be worried or it is normal with antibiotics?
Hello Mamie, this might be caused a result of the antibiotics.
I’m sorry if any of this is too TMI but I’ve been on 4 antibiotics plus several other medications a day for the past 2 weeks but a few days before I got sick I gave my BF a hand job and stuff got on my hands and I’m probably just stressing/over thing it too much but is there a possibility of being pregnant or is it most likely the medication effecting my cycle. (I’m currently 9 days late). Much appreciated xxx
Hello Lauren, the antibiotics is more than likely the cause for the delay in your cycle.
I had sex on the 10th of March on the last day of my period.. I saw my period April, now it’s due to come may but there isn’t any sign of it coming soon. could there be any possibility that I’m pregnant
Hello Nelly, take a pregnancy test if you think you might be pregnant (7 days after a missed period).
I’m on the same boat. Any update, Nelly? I’m 8 days past my period for this month.
Speechless already. I had my last period April 3-6th. afterwards I started treating infection using dexel kits, fluconazole,and loratidine, with vaginal inserter. The pain reduced from my pelvic region. To date, I haven’t seen my period. though I had sex BT used postinor 2. I ran a pregnancy test as well April 30 but result was negative. Please what transpired?
Hello Faith, the use of the antibiotics might be the reason for the delay.
Hello I was on three rounds of antibiotics and steroids starting the 3/5/18 and then once again 3/21/18 however I had unprotected sex on 3/20/18 and he pulled.(sorry if TMI) I was also put on a higher antibiotic on 3/28/18 for strep yet again.. I had my period 11 days after the unprotected sex which was on March 31st and it lasted till April 4th/5th and I haven’t had a period yet.. my period tracker states I’m 10/11 days late I took a total of 2 test and both have came up negative instantly… should I be concerned?!
Hello Tiffany, this could easily be as a result of the antibiotics.
Am I pregnant or it is just the effect of the medicine I take? April 5 is my last period and had unprotected sex on April 10. Now I still don’t have my monthly period and I have been woried about it since I had my co-amoxiclav for 7 days during april 23-29. Btw the length of my period cycle is 25-26 days. Hope someone can help me !
Hi Rine, could be the effects of the medication. They can have the effect of delaying your period for a period of time. I would recommend giving it some time, maybe another week or so, but if you want to feel sure, take a pregnancy test. That’s the best way to determine if you are or aren’t pregnant though, just take a test. The $1 ones are just as effective as the more expensive ones. Plus it could just give you a peace of mind as well.
I took keflwx for seven days, 2000mg per day. I have not had my cycle in two months and two pregnancy tests said I am not pregnant, can this be from the keflex?
Hi Alexis, looking up the medication, 2000mg daily is a reasonably high dose. I would say that it could cause a delay in your period however two months seems to be an excessive amount of time. But it’s possible, not likely. I would check with your doctor on that considering the dosage as well as and see what they say. Illness and infection can also mess with your cycle too.
Hello! taking co-amoxiclav could be the reason to have your period delay? .
I had my last period on April 5 and had unprotected sex with my boyfriend on the 10th of April. My period was due on the 26th but it’s now 3 days late! I really don’t want to be pregnant. Is there a possibility that it’s the antibiotic that has delayed my period ? I’m I possible pregnant?
Hi Rine, you must have a short cycle to expect your period on the 26th. That would mean a 21 day cycle. A 28 day cycle would have put you to the 3rd of May, so if you haven’t seen your period yet, yes it could have been from the antibiotic which has the possibility of affecting your period, or you could be pregnant. Have you either gotten your period or have you taken a pregnancy test.
i got some antibiotics to take i took them and took a break from them and now my period is over 7 days it is now day 14 and i am worried and i am not sexually active!!!!!!
Hi Deje, if you aren’t sexually active then there is nothing that you have to worry about, meaning not potentially pregnant. Taking antibiotics can cause an interruption in your cycle. There really is nothing to be concerned about.