Hormone Replacement Therapy and Ovarian Function

Effects of HRT on Ovarian Function

The American College of Obstetricians and Gynecologists recommends HRT to treat symptoms of estrogen deficiency in women with premature ovarian insufficiency (POI), not to reduce ovarian size 1
Women with POI have diminished ovarian reserve and function prior to starting HRT, characterized by ovarian failure before the age of natural menopause 3
The European Society of Human Reproduction and Embryology states that HRT aims to replace hormones that are no longer adequately produced by the ovaries, rather than affecting ovarian size 3

The American Society of Clinical Oncology notes that chemotherapy and radiotherapy can cause premature ovarian insufficiency, resulting in reduced ovarian function and size before HRT is initiated 1, 2
Total body irradiation (TBI) above 10 Gy affects almost 100% of patients with gonadal failure, according to the American Society of Clinical Oncology 1
The Endocrine Society recommends HRT to manage symptoms after cancer treatment has already affected the ovaries 2

The American College of Obstetricians and Gynecologists prefers 17β-estradiol to ethinylestradiol or conjugated equine estrogens for estrogen replacement 3, 6
Transdermal administration of 17β-estradiol is the preferred route as it mimics physiological serum estradiol concentrations, according to the European Society of Human Reproduction and Embryology 1
The North American Menopause Society states that transdermal estradiol provides a better safety profile than oral formulations by avoiding hepatic first-pass effect 1

The American College of Obstetricians and Gynecologists recommends that women with POI using HRT should have a clinical review annually, with particular attention to compliance 3, 6
Ovarian function cannot be reliably assessed during HRT for contraception or gonadal failure, according to the American Society of Clinical Oncology 2, 4

The European Society of Human Reproduction and Embryology notes that HRT in women with POI has different risk-benefit considerations compared to HRT in naturally menopausal women 3
The American College of Obstetricians and Gynecologists states that women with POI should be informed that HRT has not been found to increase the risk of breast cancer before the age of natural menopause 3
HRT may have a role in primary prevention of cardiovascular disease and for bone protection in women with POI, according to the European Society of Human Reproduction and Embryology 3