Progynova and Ovarian Insufficiency: Follicle Growth, Not Menopause Reversal

Reports of follicle growth after estrogen pretreatment concern residual follicles in ovarian insufficiency—not the creation of new eggs after menopause.

Progynova, an estradiol valerate medicine, has been used in reports of renewed follicle growth and pregnancy in women with markedly reduced ovarian function. Estrogen priming aims to lower elevated follicle-stimulating hormone (FSH) and alter the hormonal environment around follicles that remain.

It does not create new eggs. Reported successes largely involve primary ovarian insufficiency (POI), in which ovarian activity may occur intermittently, rather than ordinary natural menopause.

Why lower FSH with estradiol?

When ovarian function declines, estrogen production falls and the pituitary increases FSH secretion in response. This explains the high FSH often seen in POI or menopause.

FSH stimulates follicle growth, but high levels do not ensure growth when ovarian function is severely impaired.

Estradiol valerate, Progynova's active ingredient, suppresses pituitary FSH secretion. Researchers are investigating whether this hormonal adjustment may favor growth of residual follicles.

A lower FSH value alone does not demonstrate recovery of ovarian function. Drug-induced hormone suppression and actual follicle growth are different outcomes.

Four spontaneous pregnancies in a small retrospective study

A study published in 2018 analyzed 52 women with transitional premature ovarian insufficiency.

Twenty-six received Progynova 2 mg daily with dydrogesterone added during the luteal phase for three months. Another 26 proceeded to IVF without that pretreatment.

Four of the 26 pretreated women conceived spontaneously during treatment. Lower FSH and possible improvements in ovarian response were also observed among women proceeding to IVF after pretreatment.

This small retrospective study cannot establish that Progynova directly caused those pregnancies. The regimen describes the research, not a recommendation for self-treatment.

Japanese research has also reported follicular development after hormonal treatment in POI, and clinical approaches in Korea have explored estrogen pretreatment in women with diminished ovarian function.

These reports suggest that remaining follicles may sometimes grow after hormonal adjustment. The scale of successful pregnancies and the effectiveness of individual approaches require further verification.

A case with AMH 0.03 ng/mL and one antral follicle

A Vietnamese case report published in 2026 described a 32-year-old woman with POI. Her anti-Müllerian hormone (AMH) was 0.03 ng/mL, and ultrasound identified one antral follicle.

During estradiol valerate treatment, FSH fell from 22.3 IU/L to 4.06 IU/L and subsequently to 2.48 IU/L.

The follicle grew from 17 mm to 20 mm and ultimately 23 mm. With one mature follicle identified, clinicians used intrauterine insemination (IUI) rather than IVF. The patient conceived and delivered at term.

The case illustrates possible growth of a remaining follicle despite extremely low ovarian-reserve markers. One case cannot establish that other patients would experience the same outcome.

This is not evidence that natural menopause can be reversed

Estrogen pretreatment is an investigational fertility approach in this context, not an established treatment proven to restore fertility in women with severely impaired ovarian function.

POI occurs before age 40 and may involve intermittent ovarian activity. It differs from ordinary natural menopause. Pregnancy reports in POI therefore cannot be treated as proof that egg production restarts after natural menopause.

Even if Progynova lowers FSH, ultrasound and other assessment are needed to determine whether a follicle is actually growing. A drug-induced hormone change does not mean ovarian reserve has increased.

The research concerns creating a more favorable hormonal environment for existing follicles, not making new eggs. Further studies must establish which patients might benefit and whether pregnancy and live-birth rates improve.

Research sources

Trang Nguyen Khanh Huynh and colleagues, Pham Ngoc Thach University of Medicine and Hung Vuong Hospital. “Successful Intrauterine Insemination Following Estradiol Pretreatment in a Patient with Primary Ovarian Insufficiency: A Case Report.” Journal of Reproduction & Infertility, released July 28, 2026. DOI: https://doi.org/10.18502/jri.v27i1.22125. PMID: 42633041.

“Estrogen treatment in infertile women with premature ovarian insufficiency in transitional phase: a retrospective analysis,” published in 2018. PMID: 29204869.