Anastrozole and periods

Can someone advise me please,  should I be having periods whilst taking Anastrozole?  I was diagnosed in Nov 2013,  er/pr positve stage 3,  I had chemo then wle,  full node clearance,  rads then went on Tamoxofen for 3months, this didnt agree with me so was put on Letrozole.  In Jan 2015 l had my follow up appointmet with oncologist were i explained about leg pain,  she advised me that as I was then approaching 48 and hadnt had a period since start of chemo that I was most probably post menopausal,  she organised a blood test and I subsequently received a letter to say my ovaries were no longer working and to collect my new perscription of Anastrozole.  Well since May 2015 I have been having regular monthly periods,  each month getting heavier and lasting longer,  this last month I have been bleeding since 8 Dec.   I have mentioned this continuation of periods and this month bleed to my GP who doesntt seem worried, but I am.  Can anyone share their experience please?  (sorry for the long post) 

Hi Purpleelephant, 

I am sure some of users will be along soon to share their expereince with Anastrozole.

In the meantime please do call our support lineat 0808 800 6000 who will be able to talk to you about Anastrozole and offer their support.

Best wishes, 


Digital Community Assistant 

Hi - I’ve just come across your message as the same thing is happening to me. I’m 49 and was told that my ovaries had ‘packed in’. If you don’t mind me asking, what has happened to you since?

Thank you ?

I am going through the same thing. Periods stopped during first chemo in sept 2015. Was on tamoxifen since feb 2016 and as oestrogen level were in menopausal range in Jan 2019 medication was changed to anastrozole tere. So now (may2019) I got  a period, the usual symptoms sore breast, cramps and I’m back in the system again being referred to a gynecologist for a D and C. Bloods came back as still in menopausal range. Am concerned but trying to reason it out. I was not menopausal before I started chemo so it was a chemical menopause. Does this make a difference? ? ?

I am 66 next month Jan 2023 and started on drug in Sept 2022.  I started bleeding vaginally on Christmas Day and 3 days later am still bleeding.  Am also feeling as I did for over 40 years when I had my period, depressed and can’t imagine 10 more years of this.  I felt free from the age of 58, (after one day in month thoughts of suicide from age 13 to 58 during period).  Not the same as being suicidal!  I sympathise with all on this drug.