Recombinant LH supplementation during ovarian stimulation modulates early embryo morphokinetics without affecting IVF...

Whereas luteinizing hormone (LH) contributes to steroidogenesis and oocyte maturation, its influence on embryo developmental kinetics has not been previously investigated using time-lapse technology. The aim of this retrospective analysis was to assess embryo morphokinetics following rLH supplementation in expected normal responders undergoing ovarian stimulation and evaluate associated embryological and reproductive outcomes.

A total of 120 patients were stimulated with either rFSH + rLH (n = 60) or rFSH alone (n = 60). Overall, 927 embryos were cultured in the Geri plus® time-lapse system and annotated for key morphokinetic parameters, including pronuclear dynamics, cleavage stages, morula formation, and blastocyst development. Clinical outcomes following fresh and frozen embryo transfer were also compared between groups.

No differences were observed in baseline characteristics or ovarian stimulation outcomes, including oocyte yield, fertilization rate, cleavage rate, or usable blastocyst rate. Clinical pregnancy, miscarriage, live birth, and cumulative live birth rates were comparable between the two treatment groups. Embryo morphological quality was similar in both groups. Time-lapse analysis revealed that embryos derived from rFSH + rLH cycles exhibited accelerated early developmental kinetics, characterized by earlier pronuclear appearance, pronuclear fading, and first cleavage. In contrast, subsequent cleavage timings and later-stage morphokinetic parameters were comparable between groups. No differences in morphological or morphokinetic features were observed among implanted blastocysts.

rLH supplementation during ovarian stimulation modulates specific early zygotic events without affecting later embryo development, implantation, or live birth, indicating that routine rLH addition does not alter embryo competence in expected normal responders.