Dancinggirl and Tinkerbell are right (unless there are some very new recommendations that means we're all out of date!). The GP is thinking about Mirena and contraception.
That study that Menopause Sucks linked to refers to contraception not HRT. The Mirena does not run out of progestogen after the given time but the release rate is such that it is much lower year on year so that it cannot be guaranteed to keep the lining thin after this period of time has elapsed. Obviously if you have a very low dose oestrogen then it will last longer – other things being equal – although in post-menopausal women very low dose of oestrogen and Mirena are probably not advised due to potential for overthinning and endometrial atrophy.
I posted recently with the published release rates of levonorgestrel of the Mirena and Jaydess so you can see for yourself:
"For anyone that wants to look up the data and info that I quoted the SPCs (detailed product info) are here:
https://www.medicines.org.uk/emc/medicine/28672/SPC/Jaydess+13.5+mg+intrauterine+delivery+systemhttp://www.medicines.org.uk/emc/medicine/1829/spc/mirena/You can see that from the start the Jaydess contains approx a quarter of the total amount of levonorgestrel that the Mirena has (13.5 mg vs 52 mg).
Mirena delivers Levonorgestrel initially at 20 mcg per 24 hours, reducing to 10 mcg after 5 years and extrapolated to be approx 12 mcg after 4 years (when it is recommended to be renewed for HRT purposes).
Jaydess delivers 13.5 mcg per day initially reducing to 5 mcg after 3 years.
Systemic concentrations with Mirena are approx: 276 pg/ml after 1 yr, 196 pg/ml after 2 yrs and 177 pg/ml after 3 years. With Jaydess the data give 162 pg/ml after 7 days and 59 pg/ml after 3 yrs - so much lower, but there is a wide variability in these levels amongst the women measured. All this info is from the Summary of Product Characteristics (SPC) on the web and possibly the company website ."
Posted on this thread:
http://www.menopausematters.co.uk/forum/index.php/topic,33744.msg541447.html#msg541447Hurdity x