True empty follicle syndrome is a subtype of oocyte maturation abnormalities

To review the outcomes of in vitro maturation (IVM) and in vitro fertilization (IVF) in women with empty follicle syndrome (EFS). The study evaluated the genetic underpinnings of EFS by analyzing mutations.

This retrospective case series involving 17 women with EFS over at least 2 IVF cycles was conducted. The study also employed whole-exome sequencing to analyze the genetic mutations. The treatment approaches included letrozole-primed IVM, follicle-stimulating hormone (FSH)-human chorionic gonadotrophin (hCG)-primed IVM, and conventional IVF.

The average female age was 31.5±4.6 years, and the duration of infertility was 7.3±3.5 years. Four patients underwent IVF. IVM oocyte collections yielded oocytes in 12 of 13 subjects. Of these, 75% (9/12) yielded MII oocytes after 48 h of IVM media incubation. Six subjects had fertilized embryos, resulting in a 40.9% intracytoplasmic sperm injection (ICSI) fertilization rate (9 embryos/22 MII oocytes). Genetic analysis revealed mutations in seven patients. This study demonstrated the partial efficacy of letrozole-primed IVM plus growth hormone and FSH-hCG primed IVM protocols. No pregnancies or live births were recorded after IVM. One ongoing pregnancy post-IVF and one spontaneous live birth were observed.

Inter-cycle variabilities were observed in women with oocyte maturation abnormalities (OMAs). Almost all patients with EFS had oocytes collected during IVM following IVF. These oocytes have limited potential for maturation, fertilization, and live birth, as demonstrated by the low rates observed after IVM culture and ICSI. These conditions are observed in OMAs due to defects in the oocyte machinery. The proposed flowchart provides a comprehensive classification approach for various forms of EFS.