effect of antibiotics on menses

I have cystic fibrosis and have been taking flucloxacillin for as long as I can remember and have always had a normal period. I came across this site because I believe I am pregnant due to the fact that my perios is late, and that is strange for me, and just wondered if any of my meds might affect the result of the pregnancy test.

you can still get pregnant even on your period because sperm can live inside yu for days...

(sorry for spelling mistakes) i am on amoxicillin for an abcess in my mouth asnd have been for the last 2 weeks, i was very sick with sun stroke and then very sick with the abcess, i am 5-6 days late and i am on a contreceptive pill, i am very worried but have taken a pregnacy test which was negative ! i was going to ring up the doctors and make an emergency appoinment for this morning but after reading all of these comments i think i will chill out slighlty and maybe take another test next week just to be sure :)

I was on Bactrim (not sure if spelled correctly) an antibiotic for a "sinus infection" and my period was 2 days late and lasted less than 24 hours. I went to OBGYN doctor today to rule out pregnancy and she "thinks" my period or lack there of was affected by the meds. Im not so sure...because my period before the antibiotic was a little off too...but my urine sample was negative for pregnancy and so I asked her to do a blood test and I have to wait 2 days for the results. not only thst, but I have had a few symtoms of pregnancy also...and I am still taking my birth control pill, have Not missed a single dose either.

I'm on bactrum (sp?) for a second round of infection and I've had the opposite problem. My period seems to be lasting forever!  I think it's been 2 weeks. It's not heavy, but I'm definatly still going through tampons.

I am currently taking Amocicillan, or however it's spelled, and I am having problems with my period too. I have been on it now for eight days, and was, until last night, six days late for my period. I got my period last night, but now, only seventeen hours later, it seems I am done with it. I bled so lightly that the whole period only took one tampon use. This has never happened to me otherwise. I am usually VERY regular. So much so that I have the exact days on the calendar when I start and stop all my periods, so...I'm assuming it is because of the antibiotics. I know I'm not pregnant.

Hello,

Could any of you please confirm if you got your periods after 2 weeks delay because of pencillin?

Cheers

Planned my vacation around my period, took antibiotics for 10 days, now my friend is 5 days late and my trip is in a week!  My period has been regular for over a year.  I am certain the antibiotics effected my cycle.    

I was recently on a 7-day oral antibiotic treatment for BV. It is now a week after my last dose, and I am still having side-effects... gross taste in my mouth, vaginal dryness (also unable to get aroused when I used to always have tonnes of vaginal liquid when I was sexually active), and my period is at least 2 days late now. I am a lesbian so I know I'm not preggo. I am really freaking out that this is going to affect me sexually and potentially affect my having children in the future :( Have you had these problems and did they get better? I have been taking probiotics and also eating lots of anti-oxidants to help counterract the harm the drugs might have caused. Please help...

I have read all these posts and am quite relieved. I had a 5 day course of penicillin which failed to completely clear an infection from a root canal so the doc put me on a second 7 day course of Amoxicillin and two days in I am having the weirdest spotting. Very light and really irregular. Rather than panick now in going to wait for the meds to clear my system and take lots of probiotics, eat raw and healthy and see if it all clears up in a couple cycles.

My name is Karin. 

I took Keflex for 5 days for a possibly infected cut.  I am on the pill and had unprotected sex the day before I started taking the antibiotic. I haven't had sex at all since being on the antibiotic.

My period is always on time, but this time it is extremely light (only see dark brown/blood tinges when I wipe.. sorry for the TMI).  It has been like this for 4 days. I usually start out that way and then I go full force for a few days but this time it's just light.

So I am having the symptoms too. I'm kinda freakedout that I might be pregnant becuase of that incident and when I started antibiotics , perhaps it decreased effectiveness. However, I asked two pharmacists about this. I called Telehealth and the pharmacist said there is no interaction listed there for birth control with Keflex. The other pharmacist whom I purchased the medication from warned me that it does iin fact interact with Birth Control . I asked him if it was okay that I had sex the day before, and he said yes it's fine.   I suppose it's good I'm getting alittle bit of bleeding at least to calm my nerves but I'm wondering if I'm preggers becuase it is so incredibly light.  I try not to get pregnant-worried during my period (I worry every month even if I haven't had sex!... and reading anything on the internet doesn't help!) but I can't help but be kind of weirded out. 

Keflex, I have to mention, also has done a number on my body joint-wise. This is not mentioned anywhere. But i had horrible back pains a few days after I stopped the medication, and it has lasted for about 1 week. Pains in my back and knees/legs.   I am only starting to feel a little better 20 days after stopping the meds..

AND Crystal, just give it time. Don't worry. I think the drugs just need to get out of your system. You also sound really stressed about it, and that is not helping your body at all. It's making you extra aware of your body as it's getting back to normal. It's insane what stress can do to you... stress from an injury can sometimes be more harmful than the injury itself! See below about my back problems. I am finally starting to feel better after 2 weeks since being OFF the meds.

Antibiotics can do wonders on your body. look at how it's affecting people's periods, as well. THat's testament to how powerful they can be while they're in your system. It cna take your body awhile to get back into "regulation". I'd give it a month or two, since we ladies seem to work in monthly cycles.

Only after I decided to stop worrying and just go about my life, my back problems got bettter. Things will get back to normal, try not to worry as you are!

I took probiotics too, that will help you I think.

it's karin again.  just wanted to update on what happened.

I never did get my period, only really really light as mentioned above. I took a pregnancy test a week after my missed period, and am not pregnant. I doubt stress or my only-possibly-infected cut on my finger could've caused this, after never missing a period for 10+ years. 

So girls... if you take Keflex/Cephalexin/ some other antibiotic.... don't freak out about being pregnant just because you missed/delayed/light period.. cuz I certainly did. Obviously take a pregnancy test if you do miss it, and if you think it's a possibility, just to be sure.

I was told Keflex can mess with birth control by a pharmacist, and although I'm not a doctor, I think I cna fairly rationalize that keflex messes with your hormones, and in turn can also mess with your period schedule. 

Women should be warned about this! 

Make sure you use back up contraception while on KEFLEX. I was told by a different pharmacist + doctor that it has no effect on birth control pills, but it MUST.

thankyou, you have put my mind at ease!

For YEARS I have been spot on with my menstrual cycle! Started taking Cephalexin (which I was prescribed for, for acne by a dermatologist) 4 weeks ago and now I am late 3 days late! Have sore breasts, headache today..... but no period! Did a digital pregnancy test - negative. After reading these posts I question whether this is due to the antibiotic....?? I do have a partner so there is a chance I could be pregnant however being late is REALLY out of the normal for me...... I will be doing another test in afew days!