I have been on Tamoxifen for just over a year & during that time my periods have been more regular than ever, 4 weeks apart.
This month I am 6 days late (took a pregnancy test today which was negative). Is it possible for periods just to stop suddenly without any warning on Tamoxifen? It just feels odd given they have been so predictable.
I am due to have a CT scan next week as I have lost nearly 15% of my body weight since diagnosis and my BMI is 19.1
My recent blood tests have all come back normal though so don’t think the CT scan will find anything untoward. Perhaps Tamoxifen is causing the weight loss.
Anyone else with similar experiences, I would be very grateful to hear from xx
Good luck with your scan . My periods stopped when I started Tamoxifen but I was early 50s . I know other people I spoke to ended up with very unpredictable periods . You could also ask the nurses advice in the Ask the Nurses section ?
best wishes Jill x
My experience is a little different to yours, but may be helpful to share anyway.
I was diagnosed aged 35, and when I started taking tamoxifen, my periods went from being like clockwork (28-29 days apart) to being incredibly irregular - anything from 14 to 42 days apart. I started to keep a diary to track my periods and after about 5 years on tamoxifen, I noticed they’d started to settle. They’ve been about 29-31 days apart for the last 2 years (still on tamoxifen). I think we all respond differently to tamoxifen, but it’s not unusual for periods to become less predictable while taking it. Also, I’m not sure how old you are, but if you are 40 or older, it’s possible you may be entering the peri-menopause, so your periods may become irregular anyway, whether you are taking tamoxifen or not.
I also lost quite a bit of weight to begin with and had a similar BMI of 19. I lost 6 lbs in 6 weeks without trying and was really worried. A CT scan and blood tests showed everything was fine so I just put it down to tamoxifen. I think it plays havoc with fluid retention, in the way that hormones can. When I first started taking tamoxifen, I was going for a wee all the time, and had to get up 3, 4 or 5 times each night to go to the loo. This has improved over time, but I still have to get up 2 or 3 times a night. The only exception is in the few days before my period, when I don’t have to get up at all. Pre-menstrual fluid retention is a pain, but at least it gives me a decent night’s sleep!
Anyway, I really hope your CT scan results also come back clear and that your symptoms are just your body adjusting to long-term tamoxifen therapy. I’ve certainly had a whole range of side effects, some new, some old and some almost from day 1.
I wondered whether you ever figured out whether the tamoxifen was the cause of this? I’m having a similar experience - been on it for nigh on 2 years, and after initial irregularity, for at least a year my periods have been like clockwork but now I’m 5 days late (and definitely not pregnant). I’m turning 40 this year so I guess it could be perimenopausal symptoms, but wondering whether it’s worth checking in with the breast cancer nurses.