Identifying Predictive Bacterial Markers from Cervical Swab Microbiota on Pregnancy Outcome in Woman Undergoing Assisted Reproductive Technologies.

BACKGROUND AND AIMS: Failure of the embryo to implant causes about three-fourths of lost pregnancies. Female genital tract microbiota has been associated to Assisted Reproductive Technologies (ART) outcomes. The objective of this study was to analyze the microbiota of human cervical swab and to correlate these findings with the ART outcomes. MATERIALS AND METHODS: In this study, 88 cervical swabs were collected from women undergoing ART cycles, with various causes of infertility, at the beginning of the ART protocols. After microbial DNA extraction, V3-V4 variable regions of the 16S rRNA gene were amplified and sequenced on the Illumina MiSeq platform. PEnalized LOgistic Regression Analysis (PELORA) was performed to identify clusters of bacterial populations with differential abundances between patients with unfavorable and favorable pregnancy outcome groups, respectively. RESULTS: We identified a core of microorganisms at lower taxonomic levels that were predictive of women's pregnancy outcomes. Statistically significant differences were identified at species levels with Lactobacillus salivarius, Lactobacillus rhamnosus among others. Moreover the abundance of Lactobacillus crispatus and iners, respectively increased and decreased in favorable group as compared to unfavorable group, resulted within the core of microorganisms associated to positive ART outcome. Although the predominance of lactobacilli is generally considered to be advantageous for ART outcome, we found that also the presence of Bifidobacterium (together with the other lactobacilli) was more abundant in the favorable group. DISCUSSION: Cervix is colonized by microorganisms which can play a role in ART outcomes as seen by an overall decrease in embryo attachment rates and pregnancy rates in both fertile and infertile women. If confirmed in a larger cohort, the abundance of these bacteria can be useful not only as a marker of unfavorable pregnancy outcome but also they may open the way to new interventional strategies based on genital tract microbiota manipulation in order to increase the pregnancy rates in woman undergoing assisted reproductive technologies.

Chromosome Missegregation in Single Human Oocytes Is Related to the Age and Gene Expression Profile.

The growing trend for women to postpone childbearing has resulted in a dramatic increase in the incidence of aneuploid pregnancies. Despite the importance to human reproductive health, the events precipitating female age-related meiotic errors are poorly understood. To gain new insight into the molecular basis of age-related chromosome missegregation in human oocytes, we combined the transcriptome profiles of twenty single oocytes (derived from females divided into two groups according to age <35 and ≥35 years) with their chromosome status obtained by array comparative genomic hybridization (aCGH). Furthermore, we compared the transcription profile of the single oocyte with the surrounding cumulus cells (CCs). RNA-seq data showed differences in gene expression between young and old oocytes. Dysregulated genes play a role in important biological processes such as gene transcription regulation, cytoskeleton organization, pathways related to RNA maturation and translation. The comparison of the transcription profile of the oocyte and the corresponding CCs highlighted the differential expression of genes belonging to the G protein-coupled receptor superfamily. Finally, we detected the loss of a X chromosome in two oocytes derived from women belonging to the ≥35 years age group. These aneuploidies may be caused by the detriment of REEP4, an endoplasmic reticulum protein, in women aged ≥35 years. Here we gained new insight into the complex regulatory circuit between the oocyte and the surrounding CCs and uncovered a new putative molecular basis of age-related chromosome missegregation in human oocytes.

Is there a critical endometrioma size associated with reduced ovarian responsiveness in assisted reproduction techniques?

This study investigated the relationships between ovarian endometrioma size, ovarian responsiveness and the number of retrieved oocytes following ovarian stimulation. A prospective study was conducted in a public clinical assisted reproduction centre. A total of 64 infertile women with monolateral endometriomas undergoing IVF or intracytoplasmic sperm injection were included in the study. The total number of follicles, number of follicles ≥ 16 mm and number of oocytes retrieved of ovaries containing endometrioma and normal ovaries were compared. Multivariate linear regression was used to assess whether number of follicles and collected oocytes varied by endometrioma size, age, basal FSH concentration. Significantly lower numbers of follicles ≥ 16 mm (P = 0.024) and oocytes retrieved (P = 0.001) in the ovaries containing endometrioma were observed. In patients with endometriomas ≥ 30 mm, endometrioma size was the most influential contributor to the total number of follicles and oocytes retrieved. Ovarian endometriomas result in reduced response to ovarian stimulation, compared with the response of the contralateral normal ovary in the same individual. In case of endometriomas <30 mm, basal FSH concentration remains the most important prognostic factor for oocyte retrieval.