Oocyte Scoring Enhances Embryo-Scoring in Predicting Pregnancy Chances with IVF Where It Counts Most

Abstract

ContextOur center’s quality improvement optimization process on many occasions anecdotally suggested that oocyte assessments might enhance embryo assessment in predicting pregnancy chances with in vitro fertilization (IVF).ObjectiveTo prospectively compare a morphologic oocyte grading system to standard day-3 morphologic embryo assessment.Design, Setting, PatientsWe prospectively investigated in a private academically-affiliated infertility center 94 consecutive IVF cycles based on 6 criteria for oocyte quality: morphology, cytoplasm, perivitelline space (PVS), zona pellucida (ZP), polar body (PB) and oocyte size, each assigned a value of -1 (worst), 0 (average) or +1 (best), so establishing an average total oocyte score (TOS). Embryo assessment utilized grade and cell numbers of each embryo on day-3 after oocyte retrieval. Clinical pregnancy was defined by presence of at least one intrauterine gestational sac.InterventionsStandard IVF cycles in infertile women.Main Outcome MeasuresPredictability of pregnancy based on oocyte and embryo-grading systems.ResultsAverage age for all patients was 36.5 ± 7.3 years; mean oocyte yield was 7.97± 5.76; Patient specific total oocyte score (PTOS) was -1.05 ± 2.24. PTOS, adjusted for patient age, was directly related to odds of increased embryo cell numbers (OR 1.12, P = 0.025), embryo grade (OR 1.19, P < 0.001) and clinical pregnancy [OR 1.58 (95%CI 1.23 to 2.02), P < 0.001]. Restricting the analysis to day three embryos of high quality (8-cell/ good grades), TOS was still predictive of clinical pregnancy (OR 2.08 (95%CI 1.26 to 3.44, P = 0.004). Among the 69 patients with embryos of Grade 4 or better available for transfer 23 achieved Clinical Pregnancy. When the analysis was restricted to the 69 transfers with good quality embryos (≥ Grade 4) the Oocyte Scoring System (TOS) (AUC±SE 0.863±0.044, oocyte score) provided significantly greater predictive value for clinical pregnancy compared to the embryo grade alone (AUC 0.646 ± 0.072, embryo grade) p = 0.015.ConclusionsOocyte-scoring, thus, provides useful clinical information especially in good prognosis patients with large numbers of high quality embryos. This finding appears of particular importance at a time when many IVF centers are committing sizable investments to closed incubation systems with time-lapse photography, which are exclusively meant to define embryo morphology.

Effect of GnRH analogues for pituitary suppression on oocyte morphology in repeated ovarian stimulation cycles

“…Oocyte quality is an important factor that influences the developmental and implantation potential of derived embryos (Lazzaroni-Tealdi et al, 2015). In assisted reproduction, heterogeneity in oocyte quality is quite common.…”

Impact of Oocyte Morphology on Fertilization, Embryo Quality and Pregnancy after ICSI: Evaluation with Diabetes and PCOS

“…It was reported that determining pregnancy potential at the oocyte level rather than the embryo level might provide an insight into the embryo selection for transfer. A previous Study suggested the oocyte scoring as a cheaper method than closed incubation systems with time-lapse photography [8]. Another research had focused on the embryo quality as the best for pregnancy chances, and had concentrated on improving embryo rather than oocyte assessment, which leads to increasing the cost as the closed automated incubation systems with time-lapse photography [9].…”

Does oval oocyte have an impact on embryo development in in vitro fertilization?

“…The correlation between oocyte quality, embryo development, and in-vitro fertilization (IVF) outcomes has been widely studied (Lazzaroni-Tealdi et al ., 2015). Some studies revealed that successful pregnancy outcome with IVF/intracytoplasmic sperm injection (ICSI) depended on several variables including oocyte and sperm quality (Savitha et al ., 2012; Braga et al ., 2013; Ebner et al ., 2006).…”

“…Oocyte and embryo quality were assessed based on morphological features (Lazzaroni-Tealdi et al ., 2015; Braga et al ., 2013; ALPHA Scientists In Reproductive Medicine & ESHRE Special Interest Group Embryology, 2011). However, the correlation between these ''abnormal'' oocyte morphotypes, fertilization rates, and embryo development is still unclear.…”

“…The most frequently observed oocyte morphologic variations are cytoplasmic changes, including granularity, darkness, vacuole presence. Extracytoplasmic variations are oocyte shape, zona pellucida (ZP), perivitelline space (PVS), and polar body morphology (Savitha et al ., 2012; Lazzaroni-Tealdi et al ., 2015; Braga et al ., 2013). Oocyte dimorphism such as oval (ovoid) oocyte or other abnormal oocyte morphology may affect fertilization rate and embryo development (Ebner et al ., 2000; 2008; Xia, 1997; Serhal et al ., 1997).…”