After confirming ovarian rest (follicles < 10 mm) with menstruation by means of vaginal ultrasound, an ultrasound control of the natural cycle will be carried out, inducing ovulation when an ovulatory follicle of size ≥ 17mm and an endometrium ≥ 7mm are found. Serum estradiol and progesterone values will be determined that day. This induction will be carried out with an ampoule of 250 μg of rHCG (Ovitrelle®). After the injection of Ovitrelle®, the administration of micronized vaginal progesterone (Progeffik® or Utrogestan®) 200 mg/ 12 hours and 7 days after the injection, thawing and transfer of a frozen euploid blastocyst will begin 48 hours later.

After confirming ovarian rest (follicles < 10 mm) with menstruation by vaginal ultrasound, hormone replacement therapy with oestrogens (6 mg/day of oral oestradiol valerate - Progynova® or Progyluton®- or 150 ug/48 h of oestradiol in patches - Evopad®) will be started on day 2-3 of the cycle. On day 10-15 of treatment an ultrasound scan will be performed to assess endometrial growth and ovarian rest. After confirming an endometrial thickness ≥ 7mm by vaginal ultrasound, ovaries with follicles smaller than 10 mm, blood estradiol >100 pg/ml and serum progesterone < 1 ng/ml, luteal phase support will begin with the administration of 400 mg of micronized vaginal progesterone every 12 hours, a total of 10 shots, prior to embryo transfer of a thawed euploid blastocyst. same day. If the level of serum progesterone on the day of transfer is less than 9.2 ng/ml, a daily injection of subcutaneous progesterone (Prolutex®) will be added on the same day.

The intervention group will be prepared with hormone replacement therapy with estrogens according to usual clinical practice. Frozen embryos will be transferred after ten doses of exogenous progesterone.

Presence or absence of pre-eclampsia during pregnancy

Presence or absence of Bleeding during pregnancy

Presence or absence of Hypertension during pregnancy