This is the first study with a real diagnostic and prognostic focus in prenatal. In addition to this innovative aspect, the identification of cryptic imbalances in fetuses with malformative syndrome would be an invaluable resource for the identification of new genes involved in development, as is already the case for postnatal studies.

This research aims to:

1. to test the feasibility of this protocol, ie the practical application of this new technology in the context of prenatal diagnosis,
2. demonstrate and evaluate the possible involvement of cryptic chromosomal abnormalities in fetuses with a thick neck associated with other malformations and recruited on the strict criteria mentioned above,
3. assist in the diagnosis of these fetuses and genetic information for their families,
4. identify new regions of the genome potentially involved in the occurrence of congenital malformations.

Inclusion Criteria:

• a karyotype performed from a trophoblast biopsy or an amniotic fluid puncture is normal or apparently balanced.
• The fetuses included in the study should have one of the following two criteria:
• 1) Thick bone (greater than 99th percentile, between week 11 and week 13 of amenorrhoea plus 6 days, correlated to a cranio-caudal length measured between 45 and 84 mm) detected in the first trimester of pregnancy associated with One or more echographic sign (s).
• 2) At least two ultrasound call signs involving the following organs (heart, kidney, brain, limbs, digestive tract, face) or intrauterine growth retardation (less than 3rd percentile) associated with one of these Signs of appeal.

Exclusion Criteria:

• The parturientes in emergency situation,
• Benefiting from a legal protection (guardianship / curatorship)

200 parturientes aged 18 to 45 years

the parturients aged 18 to 45 years for whom a karyotype performed from a trophoblast biopsy or amniotic fluid puncture is normal or apparently balanced