Failure of Meiotic Competence in Human Oocytes1

Abstract

The administration of hCG to women undergoing in vitro fertilization and embryo transfer (IVF/ET) results in the meiotic maturation of cumulus-oocyte complexes (COC). Sometimes oocytes being aspirated for IVF/ET fail to resume meiosis in vivo and even after a subsequent 20-h incubation in vitro and are thus defined as meiotic competence failure (MCF) oocytes. The relationship between the proportion of MCF oocytes and other IVF/ET outcomes was studied over 3 years in 703 tested cycles of 487 women. Women yielding one or more MCF oocytes in at least one menstrual cycle represented 8.6% of this population and were defined as MCF women. Cumulus state in the MCF oocyte population was characterized as mature in 57.4 +/- 6.7%, intermediate in 13.9 +/- 4.0%, immature in 24.1 +/- 8.7%, and atretic in 4.6 +/- 2.7%. These values differed significantly, by 0.6-, 2.9-, 7.1-, and 4.6-fold, respectively, as compared to the corresponding COC aspirated from women yielding only meiotically competent (MC) oocytes. In a menstrual cycle yielding both MC and MCF oocytes, the IVF/ET variables were evaluated in the MC oocytes. Thus, in such cases the incidence of fertilization or cleavage and the number of blastomeres per embryo were significantly reduced concomitant with the increase in percentage of MCF oocytes. When the percentage of MCF oocytes was 25% or more, no pregnancy was achieved. Various follicular parameters and serum 17 beta-estradiol (E2) and progesterone (P4) levels were compared in MC and MCF women over the four days preceding day of aspiration.(ABSTRACT TRUNCATED AT 250 WORDS)

Oocyte maturity in repeated ovarian stimulation

“…Bar-Ami et al [10] reported that meiotically incompetent oocytes are retrieved in 8.6% to 15.2% of all infertility patients and also demonstrated that if >25% of the oocytes were immature, then successful fertilization and clinical pregnancy were greatly reduced [10]. The other studies also demonstrated that a positive correlation exists between the degree of nuclear maturation and their potential for fertilization in vitro [11,12].…”

“…The meiotic division of the mammalian oocyte is under several stop/go control and influenced by various components of the oocyte and the follicle [10]. It starts before or after birth and restricted in status of meiotic arrest at the diplotene stage by an inhibitory follicular environment [15] and the LH surge lifts this restriction and stimulates the maturation of oocytes to the first PB stage [2].…”

Oocyte maturation failure: a syndrome of bad eggs

“…Approximately 8.6% to 15.2% of all infertility patients produce at least one meiotically incompetent oocyte (3, 4). If >25% of the oocytes were immature, then successful fertilization with clinical pregnancy was greatly reduced (3).…”

“…If >25% of the oocytes were immature, then successful fertilization with clinical pregnancy was greatly reduced (3). Importantly, the occasional production of an immature oocyte is to be distinguished from a syndrome of repeated oocyte maturation failure where there is repeated production of a majority of immature oocytes.…”

Maturation arrest of human oocytes at germinal vesicle stage

“…[2] Normally, in conventional protocols by the time of retrieval, the majority oocytes have completed their maturation and are collected at the metaphase II (MII) phase. Although it is common for a few oocytes to remain immature despite ovarian stimulation and human chorionic gonadotrophin (hCG) administration,[3] the complete failure of all oocytes at GV stage to mature in vivo is extremely rare, and only a few of such cases have been described in the literature. [48]…”