Progesterone-primed cycles result in slower embryos without compromising implantation potential and with the advantages of oral administration and potential cost reduction.

OBJECTIVE: To study the impact of the use of progesterone on embryo morphokinetics and on the outcomes of intracytoplasmic sperm injection (ICSI) cycles.

DESIGN: Cohort study SETTING: Private university-affiliated in vitro fertilization center.

PATIENTS: The study included 236 freeze-all ICSI cycles and the resultant 2,768 injected oocytes cultured in a time-lapse imaging (TLI) incubation system. Patients were matched by age and divided into groups depending on the protocol used to prevent the LH surge: progestin-primed (n=144 cycles and 1,360 embryos) and GnRH-antagonist group (n=144 cycles and 1,408 embryos).

INTERVENTIONS: The kinetic recorded markers were time to pronuclei appearance (tPNa) and fading (tPNf); time to two (t2), three (t3), four (t4), five (t5), six (t6), seven (t7), and eight cells (t8); time to morulation (tM); time to start of blastulation (tSB); and time to blastulation (tB). The durations of the cell cycles and the time to complete synchronous divisions were calculated. The KIDScore ranking was recorded. Morphokinetics and clinical outcomes were compared between the groups.

RESULTS: Slower tPNa, t2, t7, tSB, and tB were observed in embryos derived from progestin-primed cycles than in those from the GnRH-antagonist group. No significant differences were noted in any other morphokinetic milestone. Significantly higher cancellation and implantation rates were observed in the progestin-primed group. However, no significant differences were noted in the pregnancy and miscarriage rates. The expense for treatment using premature GnRH antagonist was U$318.18 and using progestins was U$ 11.05.

CONCLUSIONS: Exogenous progesterone replaces the GnRH antagonist for the prevention of premature LH surge, in freeze-all cycles, with the advantage of oral administration and potential cost reduction.