Corifollitropin Alfa and Embryo Morphokinetics

Morphokinetic parameters of embryo development have been intensively investigated. However, little attention has been paid to the influence of ovarian stimulation on morphokinetic parameters. Gryshenko et al. found a significant difference in the fourth cell division time (t5) of embryos obtained after controlled ovarian hyperstimulation in long GnRH agonists and GnRH antagonist protocols. Furthermore, higher gonadotropin doses were found to slow down the development of the embryos.

Hence, the aim of this study is to investigate the influence of corifollitropin alfa (Elonva) on embryo morphokinetics and fertility treatment outcome in comparison to a control group stimulated with Follitropin beta (Puregon). The investigators hypothesize that there are differences in morphokinetic behavior of embryos within the different stimulation protocols.

A total of 742 embryos from 215 different patients suffering from infertility undergoing ovarian stimulation with Elonva and a total of 5148 embryos from 1136 patients undergoing ovarian stimulation with Puregon will be retrospectively analyzed. To exclude environmental factors the evaluation will distinguish between embryos cultured under 21% oxygen and embryos with reduced oxygen conditions (5% oxygen) in the embryoscope. Groups will be age and BMI matched.

All women included in the study underwent GnRH (Gonadotropin-releasing hormone) antagonist protocol controlled ovarian hyperstimulation. Patients received recombinant human follicle-stimulating hormone (Elonva; MSD Sharp &Dohme GMBH, Puregon; MSD Sharp & Dohme GMBH). ELONVA was administered for 7 days with subsequent administration of Puregon (MSD Sharp & Dohme GMBH) in case of further need of stimulation. Puregon was administered for 8-10 days with dosage adaption according to age, weight, serum anti-mullerian hormone (sAMH) concentration, and hormonal status. Trans-vaginal sonography was performed after 5 days of stimulation, followed by every second day until the day of oocyte retrieval. Ultrasonographical measurement was performed using a RIC 5-9-D 4D intravaginal probe of a GE Voluson E8 BT09 ultrasound machine (both from GE Healthcare Austria GmbH). GnRH antagonist (Cetrotide, Merck KGaA) was injected to avoid premature ovulation. Triggering was initiated 35 h before oocyte retrieval, administered with 5000-10,000 IU human chorionic gonadotropin (hCG) subcutaneously (Pregnyl, N.V. Organon), with dosage adaption according to body weight of the patient.

Follicles larger than 10 mm in diameter were aspirated under sedation (Propofol, Fresenius Kabi Austria GmbH; Rapifen, Janssen-Cilag Pharma GmbH) and transvaginal ultrasound guidance (GE Healthcare Austria GmbH). Follicular fluid (FF) were examined for oocytes under constant conditions of 37 °C in an IVF workstation L24E with heating stage (K-SYSTEMS Kivex Biotec A/S). Intracytoplasmic sperm injection (ICSI) was performed on all metaphase II (MII) oocytes 4-5h after oocyte retrieval according to our standard operating procedure in both groups of patients.

After oocyte retrieval and fertilization, oocytes were cultivated in universal culture medium (Gynemed Medizinprodukte GmbH & Co. KG, Germany). After 14-16 h, fertilization check was performed. All normal fertilized embryos with two pronuclei (PN) were then cultured using Embryoslide dishes in Embryoscope® time-lapse incubator (both Vitrolife AB, Sweden). With the built-in camera and microscope, images of the developing embryo were taken every 15 min in seven different layers. Definition of morphokinetic parameters was performed according to the criteria proposed by Ciray et al. and was analyzed with software developed for time-lapse image analysis (Embryoviewer® software; Vitrolife AB, Sweden).

Inclusion criteria

• Age: 18-42
• BMI: 19-29.9
• Primary or secondary infertility
• Ovarian stimulation with Elonva/Puregon
• Embryos cultured in embryoscope

Exclusion criteria

• unexpected low response
• genetic testing