Tamoxifen & Periods

I had irregular periods on tamoxifen. Started on tamoxifen in June 2016, was regular through a January 2017, then nothing for 3 months. Periods resumed May through August and were regular, then stopped. Resumed again in November. However, in October they discovered cysts suspicious for ovarian malignancy, so the ovaries were removed. Fortunately, the cysts were benign, unfortunately the periods are now over for good. The cysts grew quickly, one reached 8 cm within 6 months.Yes , I did have cramping when I was supposed to have periods but did not.

Falconer, no, I was regular like a clock at the time of the BC diagnosis, and my FSH levels were nowhere close to menopause

I went from regular periods to longer between them (it's more like a 6 to 7 week break in between). My oncologist and gynecologist both said they might completely go away and that's ok. She said if I start bleeding heavily they will take everything out, but otherwise, it is what it is. My GYN wants to do a yearly ultrasound to monitor the endometrial lining. It was normal at the first check.

I had no hot flashes and regular periods, no sign of them slowing down. Had a period mid July 2017 as normal. Started Tamox August 2017 and have not had a period since. No spotting. Nothing.

I do get occasional cramps and have wondered if it was period related. But tamoxifen has also given me some constipation problems and with that comes cramps. So I am never sure of what the source of the cramps is.

I have read a few places where transvaginal ultrasound for thickening of the uterus is not adequate to monitor tamoxifen induced changes. I was surprised to read this. Maybe over the belly ultrasound is better?

I asked my onc if tamox would stop my period, he said no. He was wrong. And that happened at half a dose a day. I do not take the full 20mg, but cut the pill in half and take 10mg some days and 20mg other days. But periods stopped on half the prescribed dosage.