The single nucleus RNA-seq approach allows the placental transcriptome to be analyzed from nuclei, thus preserving the integrity of placental syncytium. This approach is feasible on small fragments of villi and offers for the first time the possibility to consider the characterization of gene expression within the structural unit of the human placenta during pregnancy (at the 1st trimester and childbirth)

Chorionic villus biopsies are routinely performed between 11SA and 15SA at the Fetal Medicine Unit́ of the Port-Royal Maternity Hospital (CPDPN Cochin) after the patient has signed an information and consent form for the genetic analysis.

The patient will be asked to participate to the VilliRNAseq project and will sign the consent form of the study. After the cytogeneticist observation, a villi fragment will be snap-frozen in liquid nitrogen and stored at -80°C until use. Each patient sampled in the first trimester is followed until the end of the pregnancy. At delivery, cesarean section or vaginal delivery, a placental sample will be snap-frozen in liquid nitrogen and stored at -80°C until use.

Isolation, sorting and encapsidation of nuclei, RNA libraries preparation and sequencing will be carried out using 10x Genomics technology. State-of-the-art computational analyses to decipher trajectories and cell-to-cell communications.

Inclusion Criteria:

• Age 18 to 50
• Progressive monofoetal pregnancy between 11 and 15 weeks of amenorrhea
• Patient with prenatal medical indication and requesting chorionic villus biopsy with cytogenetic analysis or molecular genetics
• Patient scheduled for delivery at Port-Royal Maternity Hospital

Exclusion Criteria:

• Minor patient
• Multiple pregnancy
• Patient's objection
• Without health insurance
• Patient under guardianship or curatorship

Pregnancy

Women in their pregnancy follow-up at the Maternité Port-Royal-Cochin