P-295 Impact of Nugent score and microbiota on live birth rate after fresh embryo transfer in women with endometriosis? A tool not to be neglected!
Authors: Giorgetti C , Peel E , Chabert-Orsini V , Hairion D , Ghione S , Porcu Buisson G 
Published: June 2022

Abstract

Study question
Do altered vaginal microbiota, and vaginal leukocytosis, both estimated by the Nugent score, influence live birth rates in IVF after a fresh embryo transfer in women with endometriosis?

Summary answer
Nugent score is able to diagnose Bacterial Vaginosis and predicts its bad influence in live birth rates after fresh embryo transfer in women with endometriosis.

What is known already
For several years, special attention has been given to vaginal microbiota and vaginosis as part of IVF and embryo implantation failure.
Lactobacillus is recognized as dominant in a healthy vaginal microbiota environment while gardnerella is more present in a vaginal microbiota altered and bacterial vaginosis.
While all published studies are mostly meta-analysis, the originality of our study is the number of patients with endometriosis (223) tested in a single laboratory and taken care of by one center only. This study also reports the influence of the microbiota (gardnerella especially) and leucocytosis on LBR in case of endometriosis.

Study design, size, duration
This study is a retrospective, a non-interventional monocentric cohort study conducted between January 2017 and December 2019. 223 patients with endometriosis benefited from Nugent score for bacterial vaginosis before the start of treatment or within the first week of injections for IVF protocol. No patient was treated by antibiotics before the swab.

Participants/materials, setting, methods
Nugent score is Gram stained scoring (scale of 0 to 10) of bacterial morphotypes from vaginal smear samples calculated according to recommendations. Scores of 0-3 (Group 1) indicates normal flora, scores of 4-6 (Group 2) is considered intermediate flora and scores of 7-10 (Group 3) is diagnosed Bacterial Vaginosis (BV) (Nugent et al., 1991). In the same way, presence and abundance ok leukocytes were recorded

Main results and the role of chance
BV in endometriosis population is of 8.07% (18/223), There is no difference between the three Nugent groups regarding demographics criteria.
Concerning microbiota per se the presence of Lactobacillus is depending of age and it is statistically more represented in older patients (p = 0.04) while the presence of gardnerella is depending of indication.
Gardnerella is more represented in tubal indications and the difference is statistically significative (p = 0.01).
Concerning leukocytosis (numerous, relatively numerous and few leukocytes) or no (rare leukocytes) the difference is not statistically significant between pregnancy and failure after embryo transfer (p = 0.7).
Concerning Live Birth rate, the result is statistically different between Group 1 (31/37) versus Group 2 and Group 3 gathered (3/11) (p = 0.0008).
Furthermore, in this population with endometriosis, gardnerella is significantly associated with miscariage (p=.001)
When pregnancy has progressed favorably, the terms of delivery is not different between the three groups as well as the weight of newborns.

Limitations, reasons for caution
Our study is retrospective, which may introduce several biases despite the size of our sample i.e all all endometriosis stages were included and no differences were made based on the ethnic origins of the patients, which may have resulted in biases.

Wider implications of the findings
Nugent score is able to diagnose BV and predict its bad influence on pregnancy outcome after fresh embryo transfer in endometriosis patients.
Nugent score and its microbiota study draws the attention in this series on endometriosis patients group infected by gardnerella as it may compromise a pregnancy.

Trial registration number
NA