The purpose of this study is to evaluate the performance of non invasive screening in a population of pregnant women with and without in vitro fertilisation (IVF) concomitantly to regular first trimester trisomy 21 (T21) screening using maternal age, nucal fold measurement and serum screening.

All pregnant women in 9 institutions in France will be offer both regular first trimester screening for trisomy 21 (T21) and cell free DNA non invasive (NI) screening test at the same time. Specificity and the positive and negative predictive values of the NI test will be analysed. The population will be divided in women who did and did not get pregnant after an In vitro fertilisation (IVF) procedure.

Inclusion Criteria:

• Age >18
• Singleton pregnancy
• Having a spontaneous pregnancy or obtained by AMP ,
• Having chosen to carry out a screening of the T21 to the first or second trimester of pregnancy ,
• Gestational age >=10 weeks of amenorrhea
• Consenting to invasive prenatal diagnosis,
• Having health insurance,
• Having signed the informed consent

Exclusion Criteria:

• The Patients whose fetus has an abnormality on the first trimester ultrasound including nuchal translucency > 3.5mm ,
• Participant to another biomedical research.
• Pregnancy twins including the presence of a twin vanishing