Tamoxifen and menstrual cycle

JillCR Member Posts: 1

I have been on tamoxifen since '05 and so far my periods have been okay, I went from 28 days to 29, then even 31 days. It would only last about 3 days. Definitely is not what it used to be. I am about a week late, so of course I got a pregnancy test, 2 in fact and both were negative.  My breast are sore and I'm crampy, but nothing, what is happening?



  • hollandstat
    hollandstat Member Posts: 1
    edited September 2007

    I will start tamoxifen after I complete radiation.  It was my understanding that the tamoxifen will stop my cycle, but I see you still have one.

  • Janine
    Janine Member Posts: 1
    edited October 2007

    I have been on Tamoxifen since January 2005.  My remaining breast is tender and I'm waiting for a period.  Mine are much more erratic.  I had two last month and now nothing.  Hadn't had any for a year prior to that.  Just hate the pain in my left breast.  Ready to have it taken off but I keep thinking "It's just the Tamoxifen doing it's job".  Guess I'm not alone with weird symptoms.

  • [Deleted User]
    [Deleted User] Member Posts: 183
    edited October 2007

    My ob/gyn told me that only a percentage of women stop getting periods altogether while on tamoxifen (I forget what the percentage was; I'll have to get back to you on that). Many (if not most) women still get periods, either regularly or sporadically. I'm a few days late as well, Jill, but KNOW I'm not pregnant (h2b has been "fixed," lol). PMS and menstral symptoms without a period happen a few times a year to me and I've been on Tamoxifen for almost three years (I'll be 41 in January).

  • gina1107
    gina1107 Member Posts: 1
    edited November 2007

    I have been on tamoxifen since May 07 and have not had a period since April 07 after my mastectomy. But today i got my period after 7 months and it kind of freaked me out a bit. I thought that I wouldn't get it anymore{I'm 43}. After reading your comments though it has calmed me down. Thanks  

  • Fleurdelis
    Fleurdelis Member Posts: 1
    edited November 2007

    My period did not stop during chemo, or Tamoxifen.  Tamoxifen actually made me more regular at first, approx. every four weeks for the first time in many years, but shorter than my natural cycle, usually only 2 days instead of 3-4.  As the years on Tamoxifen went by (I'm at 4 1/2 years now), my cycle got longer.  Now I average a period every 5-5 1/2 weeks, but sometimes I go as long as 7 weeks without one.  Don't let small changes trouble you.  My gyn said they often happen.

  • awb
    awb Member Posts: 213
    edited November 2007

    my oncologist explained that 25% continue with normal periods while on tamox, 50% have irregular periods, and 25% stop altogether.  Mine became very light and irregular; had to carry mini pads with me all the time since I couldn't predict it. A yearly transvaginal ultrasound to monitor the uterine lining and the ovaries is a good idea.

  • mminmich
    mminmich Member Posts: 1
    edited December 2007

    I'm new to this board but I just started Tamoxifen about a month and a half ago. Before Tamoxifen, I had a period in June 07 (when I was first diagnosed with IDC), then nothing until late September 07 and that was a regular period lasting a week. Then I had another regular period in Oct 07. I started Tamoxifen Nov. 1.  Two weeks after I started the Tamoxifen, I had a very light 3 day period. Now, two weeks later again, I am having a light period again...Those of you with really sporadic periods, do they ever get more regular? I would hate to have a period twice every month but if it's this light, it might not be too bad.

  • amandaj
    amandaj Member Posts: 3
    edited February 2008

    I have been on tamoxifen since May 2006 but was undergoing chemo for 6 months before that.  I have not had a period in a year, but did have 2 vaginal ultrasounds since November.  My ovaries are still functioning (because there are rather large cysts and good FSH levels) but I have no signs of a period in the near future.  My gyno says that this is just how my body is reacting to everything.  She says that everyone's reaction can be different.

  • loria
    loria Member Posts: 1
    edited April 2008

    I have been on Tamoxifen since Feb. 06.  At first my cyle was regular for me 23 to 28 days, then 40 to 45 days.  Now I have not had a period for almost 8 months.  I am taking the med because of increased risk of breast cancer.  I was pre-menopausal going into the 5 yr program but now at almost 51 I could be in menopause.  I am told that if I go a full year without a cyle I will be able to take the blood test to determine if I am in menopause.  My diagnosis is ADH and would be very interested in hearing from someone who is also taking Tamoxifen for this reason. 

  • Dejaboo
    Dejaboo Member Posts: 761
    edited April 2008

    I too assumed Tamoxifen would stop ones Cycle.  I thought at least that would be nice.  I hope it doesnt make my Periods very heavy again.   I lived with that for way too many years.  When I tried birth control pills to try to lighten it..  They made it 10 times worse...(had an Endometrial Ablation- But that Only made them 'normal')

  • msvirgo828
    msvirgo828 Member Posts: 3
    edited May 2008

    Well i have been on Taxoxifen for 5 years and my period never stopped. Just off by a few days. Once it was quite late and had me run take a pregnancy test to be negative. My oncologist seems surprised everytime I go for my six month check up that I am still getting it. I also feel mixed because having breast cancer at 25 and on Tamoxifen is not common so I feel like a lab rat.

  • mistikal
    mistikal Member Posts: 3
    edited May 2008

    I finished six cycles of FAC chemo in April 08. Now I am in week 3 of radiotherapy. I had my periods all the way through chemo, only missed this month (aged 35). I have bought a pregnancy test (just in case) as I'm seeing my oncologist in July. I'm supposed to start tamoxifen after radiotherapy. I'd still like to be able to have children afterwards but it is a bit of a 'grey'/'unknown' area. 

  • KP1970
    KP1970 Member Posts: 5
    edited May 2008

    I started chemo 11/06. Chemo ended 4/07, and rads ended 8/07. My last period was 1/07. I started Tamoxifen last summer and just assumed that the chemo threw me into early menopause. I didn't realize that Tamoxifen can stop periods. Well, another 5 years of no period will be just fine with me LOL

    (btw, I'm 37 and from the time I started my period at 13, I have been very regular)! 

  • ImShelle
    ImShelle Member Posts: 2
    edited May 2008

    I was on tamoxifen nearly 3 years and had my period the whole time.  My cycle was the same number of days (6-7) and was regular.  I just got off in November to start trying for a family and then I have to finish the rest of the 5 years :( 

  • Ulla
    Ulla Member Posts: 8
    edited June 2008

    pls sisters ..

    am really confused now,,need u to tell me wat happenned with u ....

    i was 34 wen diagnosed with BC last august..now 35..

    i never lost my period during 6 chemo FEC ,

    after the chemo finished in 25 jan.my period dissappeared for 3 months(january,february,march)

    then the periods came bak in 16 april for the 1st period after chemo and rads and in may for the 2nd period after chemo and rads..

    i started my tamox in 13 may and had my 1st zoladex injection in 18 may and i thought i will not have any periods after the injection and the tamoxifen..but i had my period for this month today|!!!!!!!!!!

    is that normal?or it means that the tamox and the zoladex didnt work??????????

    am really worried

  • Eileen0417
    Eileen0417 Member Posts: 5
    edited June 2008

    Hello all, I was diagnosed at age 42. I had a period right after my second chemo. treatment(7/06) and have not had one since. It is about 2 yrs since I have had a period. I have been depressed at the idea of being menopausal, but after reading your posts, I am now thinking there could be a chance that it is my tamoxifen that is stopping my periods instead of the chemo. Are there any of you my age that lost their period for that long and got it back?

  • syren3340
    syren3340 Member Posts: 4
    edited July 2008

    Anyone having libido issues?  I'm 39 & I could care less pretty much about sex :(.

  • mistikal
    mistikal Member Posts: 3
    edited July 2008

    Hi there Ulla,

    Each woman is different. I have heard some women have their period all the way through treatment (including tamoxifen) and others who have had it stop anywhere from 6 months to 2-5 years. If you are concerned about the treatment not having effect, check with your oncologist.

    To my knowledge, the Tamoxifen does not effect your period as much as the chemo does. My understanding from the fertility specialist is that each woman's ovary production is determined at the time of birth, so by the peri (early) stage of menopause in mid to late forties less eggs are produced. Chemo, disrupts fast growing cells, like the hair, nails and bones aswell as ovary production. So the side effects are an individual thing. What we do need to do is "give our body a break" from all the changes it has gone through during 6-9 months of treatment, so it makes sense, for some women it will take at least the same amount if not, twice as long to bounce back.

    Ellen, loss of libido is perfectly normal especially through chemo week and towards the end of radiation. Our body is undergoing constant change for at least 1 year until our hair grows back to a way that is familiar to oneself. Walking or some form of gentle exercise 10-30 mins either daily or three times a week is good. I found that using a lubricant (without glycol) like Sylk helps with the vaginal dryness. Your libido will come back when you feel well and confident again.

  • FoodLady
    FoodLady Member Posts: 1
    edited September 2008

    Hi, I know this thread is a little old but I hope people like me are still reading and replying to it. I have had the opposite experience of  everyone here: very heavy periods while on Tamoxifen & Zoladex.  I had chemo in March of 07 and my periods stopped.  Started Tamoxifen and Zoladex in June of 07 and had a VERY heavy period in July, really a hemorrhage. My OB/GYN called in methergine and advised me to go to the ER if I felt weak or dizzy, which I did, but I didn't go (it was 1 AM).  It also lasted at least 7 days, and I usually was done after 3 or 4. Two months later, I had another period that was also very heavy, but maybe 30 percent less heavy than the first.  Went one year and just had a third just now in August of 08 and it was pretty heavy, much heavier than what used to be normal. I am now 40.  Has anyone else had this experience of heavy periods while on Tamoxifen and/or Zoladex?  At first my onco thought it was normal, but now suggested seeing my GYN about it. I will do this, but would like to hear from others meanwhile.  A little worried.

  • carlatreat
    carlatreat Member Posts: 1
    edited October 2008

    I have been on tamoxifen for 3 months and my periods have been horrid. The first 3 days I have to change both a tampon and pad and the tampon is the new super plus size. It's really frustrating especially at work and I don't have any pockets so I have to carry my purse to the ladie's room every time. My doctor prescribed methergine tabs 0.2 mg for my next cycle, taking 1 pill every 6  hours for three days which is supposed to cut down the amount of blood loss. Hopefully this information may be of some importance to someone.

  • awb
    awb Member Posts: 213
    edited October 2008

    my oncologist explained that while on tamox 25% will continue with normal periods, 50% will have irregular periods, and 25% will stop altogether. Mine became very irregular and very light--I got in the habit of taking mini pads with me wherever I went!  It's a good idea to have a yearly transvaginal ultrasound to monitor both the uterine ling and the ovaries.  I just finished my 5 years of tamox last week and fortunately have had mild SEs overall.


  • debestoy
    debestoy Member Posts: 1
    edited November 2008

    Hi Ladies! I was diagnised w/BC 1/06 I finished rads in 5/06 and started Tamoxifen. My cycle was normal for the first 6 months and then I only had a period every other month. I stopped taking Tamoxifen in march 08 (alot of side effects, I couldn't handle it anymore) my periods came back and 8 months later I bleed constantly. I have thickening of my endometrium but biiopsy was negative. Has anyone had a similar experience? I'm 45 now and the constant bleeding is almost as bad as all of the side effects I had on Tamoxifen.

  • Ivana
    Ivana Member Posts: 16
    edited December 2008

    Hi Strong ladies, although I am now 42, this is the closest website that relates to premenopausal women that are survivors and that discusses the issues we all face. I was diagnosed last Oct. '07 with stage IIA invasive ductal carcinoma. Went through chemo 6mo., lumpectomy (no lymph nodes involved), & radiation; finished 8/08. Started Tamoxifen in 9/07 & also had my first period since Dec. '07 that month. Haven't had one for two months & then had one this morning. It's comforting to read from others that this is normal. After this BC experience, nothing seems normal! I was doing okay on the Tamox. until the last couple of weeks I've started experiencing cramps in the back of my knees. Is anyone else having this side effect? How are you dealing with it? I'm also having menopause-like symptoms like hot flashes & mood swings. I've been taking Menopret for that on the advice of a nutritionist at UCLA. I feel like my body is very confused--doesn't know if it's menopause or business as usual! Like others on this site, I've lost all interest in sex. It's pretty sad because I really miss this part of my life. What have others tried to improve your sex drive? We use a lubricant, so I'm not uncomfortable, but just not into it. I used to have a very high sex drive & now it is less than nothing. Anyways, as you can see, lots of issues here. Any advice would be welcome since I feel that the issues for survivors between 25-50 have not been studied much. I guess because they claim it's more aggressive in younger women & their not counting on us to survive too long, (SADLY!). But I believe we are all strong fighters!

  • nash
    nash Member Posts: 146
    edited December 2008

    Hi, Ivana. Welcome to the boards. There are two threads on the boards that you may want to check out, as they pertain to some of the issues you mentioned. The first one is called "I Want My Mojo Back!", and you can find it here (sorry I can't paste live links with my browser--just cut and paste the address into your browser):


    The other thread is "Bottle O' Tamoxifen", and you can find it here:


    There are loads of women going through the same things you are, and it's really helpful to read their experiences. I feel like you do--my body is confused whether it's coming or going--I got my period back, yet I'm still having hot flashes. Very annoying. At any rate, hope those two threads help, and again, glad you found us! Smile

  • Ivana
    Ivana Member Posts: 16
    edited December 2008

    Hi Nash, thanks for your message. I checked out the other sites you recommended and they have some good advice. I'm in Southern Cal. as well. It's good to know there are others out there fighting the same battles. My tumor was also ER+/PR+ HER2-, it was 3.7cm though. Sounds like we have similar biological status. Again, thanks for your positive message. Good luck to you with the side effects--maybe they'll lessen over time?

  • nash
    nash Member Posts: 146
    edited December 2008

    You're welcome, Ivana. I started taking my Tamoxifen at night, and that seems to help in the side effects department a bit. I find my PMS symptoms are much worse since I got my period back after chemopause, though. Don't know if the Tamoxifen makes the PMS worse, or if it's just my body struggling with all the changes.

  • donnapitt
    donnapitt Member Posts: 1
    edited January 2009

    Hey Food lady,

    I'm actually glad I read your post.  I have been on tamox since Nov 2007.  while on chemo & rad no menstrual.  Had a horrible one (very heavy 7 days) in Feb 2008 and then nothing until Nov 2008 (very light one-4 days).  Now on Jan 17, 2009 the flood gates opened again (very very heavy and still not completely stopped).  I called my oncologist and they are sending me to a ob/gyn to have everything checked.  She said some people still have menstruals even while on tamox-joy!!!

  • CarlaF
    CarlaF Member Posts: 1
    edited April 2009

    Hi Loria - I see you posted in spring of 2008.  I hope you're still logging in because my situation is similar to yours.  I am 48 and also am taking Tamoxifen for increased risk due to ADH.  I began taking the Tamoxifen in November 2008.  My cycles have always been very regular.  Since starting the Tamoxifen, the first was late, and now I'm a week late again.  I feel much better after having read your post about how yours has changed as well.  I've had a few hot flashes, but the worst side effect I've noticed is irregularity.  Has anyone else noticed this?

  • McMadre
    McMadre Member Posts: 1
    edited September 2009

    Eileen, yes, I had no bleeding between mid-January 2008 and this morning.  I am 47 and thought I was post-menopausal since it had been more than a year.  But I ran out of Tamoxifen a few days ago and wasn't able to refill it until today.  I was quite shocked to find myself bleeding again.  I suppose that I might completely reverse my "menopause" if i were to discontinue the Tamoxifen.

  • woopwoop
    woopwoop Member Posts: 1
    edited September 2009

    hi everyone, well its a relief to hear im not the only one worried! ive been on tamox since jan 09, following chemo and radio, i was having periods all thru, every 3 weeks during the chemo...( i was 33 when diagnosed) when i started the tamox i stopped completely which was fine by me! then out of the blue 8 months later i had one which was very heavy and painful ive never had any pain before. so heavy that i changed before leaving work and drove home, by the time i got home less than 15 mins... i had made a mess all over the car seat! not nice! the strangest part was it arrived in the afternoon then nothing while asleep or the following morning untill about 3 in the arvo, this happened for 3 days. since this i had another 19 days later which was heavy but less so than the first. im seeing my oncologist on fri so will be asking him!