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, so my last periods lasted from the 20th to the 26th of March. I took antibiotics (josacine) for 20 days. My periods were due on the 17th of April, instead I have only been spotting since the 20th of April. Is this caused by the antibiotics?
Hi Serena, it could definitely be from the antibiotics, they have the capacity to affect your period. Have you considered or is there a possibility that you could also be pregnant? I would take a pregnancy test if you have’t gotten your actual period at this point.
I had my period on 17th march and had unprotected sex on 8 April,I was on Metronidazole from 15th-18th April. Is the drug d reason for the delay?
Hello Unik, yes the antibiotics might be the reason for your delay. However you might be pregnant given that you had unprotected sex.
Hai I did my period from 8-11 February and I had sex on 27 February my period delayed I took pregnant tests and kept on coming out negative but when I was on doxycycline they started that was somewhere 14 or 15 March but for this month not yet but I can feel the signs
Hi Sarah, are you saying you had your period on the 14th of March? Then you should be due for your next one about now, however if you are/were on antibiotics it could be a bit late. If you had your period in March after your unprotected sex, then you wouldn’t have been pregnant at that point, however if you have had some since then, you should take a pregnancy test in about a week if you don’t get your period.
I had my last period on 1st March and after which i had protected sex on 27th march…my periods are almost 9 days late and they have still not arrived…I had been prescribed a dose of amoxycillin for 5 days from 24 march. should i consult a doctor or have a pregnency test
Hello Nisha, the antibiotics is the reason for the delay in the start of your period.
I was prescribed Cefdinir 300 mg about a month ago, had my period the week before being prescribed, and its now been almost two weeks since I haven’t had my regular period cycle. I use protection when having sex, and have taken two pregnancy tests that came back negative. Can the antibiotics have something to do with my delayed/skipped period?
Hi Lauren, yes, taking an antibiotic can have an affect on your period and when you get it. If you are done with the medication I would give it another week or so, but as long as you were using protection while taking the pill, you should be fine, your body just has to get back into sync.
Hi. I took treated severe typhoid from the 4th of March to the 9th of March. I had sex with my boyfriend on the 10th of March. My period was due on the 18th but it’s now 12 days late! I really don’t want to be pregnant. Is there a possibility that it’s the typhoid and/or antibiotics that has delayed my period ? I’m really scared.
Hi Ani, It could be the antibiotics, but you have to also consider that antibiotics affect the efficiency of birth control as well if you were using some. I would recommend a pregnancy test if you haven’t gotten your period.
I got my period on the 1st of April. It’s really light though. I also took a pregnancy test and it was negative. Thank you. This was indeed helpful 😊
Hi,my name is Fred I have a pimple on my face which is to much and I decide to take Argumentin on d 27th of this month meanwhile I suppose to see my period on the second day but till now have not see my period…. Please what can cause it….is it Argumentin I tk or what?
Hi Fred, the second day of what? The second day of taking the medication? Taking an antibiotic can definitely cause your period to be delayed. Just use a second form of protection if you are sexually active as it can render your regular birth control useless (hormonal birth control). If you are concerned, wait until after your are finished with your prescription and if you haven’t gotten it by then, take a pregnancy test.
Good day my period ended on the 21/03/2018, i went to the dr on the 26/03/2018 cause i had tge flu he put me on zoxil 500mg which has pencillin. Then my period started again on the 27/03/2018, is that normal? Phoned the dr he changed it to moxibay 400mg but stil on my period the antibiotic will end on the 31/03/2018,What can be the cause of this?
Hi Kendall, being sick can wreak havoc on your body and cause changes in your period. At this point I would consider the second period your start day and go from there. However, since at this point you might be unsure as to when you are ovulating, take secondary precautions if you are using some hormonal form of birth control. If it continues for longer than expected or is accompanied by other adverse symptoms, call your doctor back.
Hi, I took ciprofloxacin for a kidney infection. My period is now 17 days late, is that normal?
Hi Amanda, yes it’s possible. Antibiotics can affect and delay your period and ovulation. Also consider if it’s possible that you are pregnant as well considering it does affect birth control as well.
Hi Jes im on the same situation as you, and im taking amoxicillin my period its 3 days late , we’re ttc as well i took first response and came back positive and took some cheapie test and got negative, Right now im so confused 🤷♀️ i dont know what to think? Its the antibiotics whos making my period and pregnancy tests crazyvor its just my body playing tricks on me!!’
I have 27-28 day cycle.
HI Gerta, it could be a false positive, evaporation lines, or the other test could have been a false negative. If you aren’t sure, take another test and go from there. The medication will not affect the pregnancy test but it can for sure affect your period.
Hi team, I am on the pill and started keflex 5 days ago but my cycle was due and is never late. I haven’t had intercourse before or during the anti biotics, so is this common that I may not have a period at all? as I am back off the sugar pill tomorrow. Should I be concerned?
Hi Coco, You period being delayed is quite possible and normal when taking antibiotics. They also pretty much render your hormonal birth control useless. I would start your new pack as usual but use a back up method for at least a week.
Hi I have been on 2000mg penicillin a day for a week now for tonsillitis and my period started the day before I started the medication. I am currently on day 9 of my period with no sign of if getting lighter. I still have 2 full days of antibiotics to take as was prescribed a 10 day course. Could this be the reason for such a long period?
Hello Amanda, the penicillin might be responsible for the current change in your period.
Hi,my periods are 3 days late and i was taking ampicillin+cloxacillin capsules for breast infection.yesterday i had very severe cramping and feeling dizzy i also have diarrhea. could the medication be the cause because I am worried.
Hello Loise, since these are symptoms you are newly having since the starting of this medication then the medication might be responsible.
Hi.Is it safe to take antibiotics during menstruation? Or do I have to wait after my period?
Hi Elle, Yes you can take antibiotics during your period.
Hello I took ampiclox 500mg for 5days I had rash on my arm and my flow was meant to come on 22nd of this month it didn’t come until 24th and when it finally came just it lasted for just 2days and stop with little blood please could the drugs be the cause
Hi there Rachael, more than likely, yes, the drugs is the reason for the delay and length of your cycle.
Hi, does the antibiotics affect monthly cycle for two consecutive months? Last month I took antibiotics on my day 9 for seven days because of severe cough and my period got delayed for about a week and even this month my period have not show up yet. How long does the antibiotics stays in body system? I’m TTC for a year already. Thanks
Hi there Jes, it normally affects the first cycle to come after the taking of the antibiotics. The antibiotics might be the cause for the delay in your period. However, since you are trying to conceive it is a good time to test for pregnancy.
Hello Alison, thanks for your response. I have 28-29 days cycle only but last month became 34 maybe because of the antibiotics and for this month its my day 36 and it didn’t come yet but I always feel its about to start, feel uneasy in my lower abdomen and feel like sharp at a times and its been a week.
Hi Jes, did you take a pregnancy test?
Yes, I did blood pregnancy test and i’ts positive yehey! I am now 6 weeks pregnant