Niveles de progesterona en fase lútea predictivos de gestación en pacientes con transferencia embrionaria

Resumen

In Vitro Fertilization (IVF) is one of the most frequently used assisted human reproduction techniques. According to the latest registry of the Spanish Fertility Society (SEF) in 2020, with success figures expressed in gestation rates per embryo transfer of 34.5% and 40.5% in fresh or frozen embryo transfer cycles respectively. Serum progesterone levels are indispensable for the outcomes of treatments, as reported by Labarta in substituted cycles with embryos derived from donated oocytes. From the investigation made with samples of patients recruited from fresh in vitro fertilization cycles and frozen embryo transfer cycles, the objective proposed in this doctoral thesis consists in determining the optimal serum levels of progesterone for the success of both treatments. It was determined that, in contrast to Labarta's study, not only is necessary to reach a minimum level of seric progesterone to increase the success rates in the cases described, but that there is also a deleterious level above which the results worsen. To improve the success rate in patients treated with vaginal progesterone in frozen embryo transfer cycles the progesterone seric concentration at d+3 or d+5 should achieve levels between 8.87-12.8 ng/ml. In in vitro fertilization cycles with fresh embryo transfer the optimal progesterone concentration value is ≥59.1 ng/ml, regardless of the date of measurement levels. It was demonstrated that the variable with the most important predictive value in predicting the level of progesterone at day +5 (Pd+5) is the progesterone seric level at day +3 (Pd+3) in both frozen embryo transfer cycles and fresh in vitro fertilization cycles. Progesterone value at day +3 (Pd+3) in both frozen and fresh embryo transfer cycles is the most useful marker to predict the progesterone level at day +5 (Pd+5). In addition, other predictors for obtaining positive ßhCG test and ongoing pregnancy at 12 weeks have been evaluated: age, body mass index, endometrial thickness, number and quality of embryos transferred, estradiol level at day -2 (before ovulation induction in fresh in vitro fertilization cycles or before the introduction of vaginal progesterone in case of frozen embryo transfer), estradiol at day +3 (three days after follicular puncture in case of in vitro fertilization cycle with fresh embryo transfer or four days after the introduction of vaginal progesterone in frozen embryo transfer cycles) and estradiol at day +5 (5 days after follicular puncture or 6 days after the introduction of vaginal progesterone in frozen embryo transfer cycles). Based on the results obtained, future studies are needed to ascertain whether the success rate of IVF cycles is improved in the case of supplementation with subcutaneous progesterone or increasing vaginal progesterone according to progesterone levels obtained on day +3, as well as with the decrease of the vaginal progesterone dose if progesterone levels on day +3 are above the optimal level.