Infections remain a major cause of neonatal morbidity and mortality worldwide. At birth, multiple microorganisms, to which they are particularly vulnerable given the immaturity and naïve nature of their immune system, may infect newborns. Passive immunity by transplacental transfer of maternal antibodies is therefore of major importance in the first weeks and months of life before their own vaccination or until this period of immunological vulnerability has passed. Some factors are known to affect transplacental passage of antibodies but these have generally been studied in small series and many other parameters have not yet been investigated. The transmission rate of antibodies, particularly neutralizing antibodies, remains little explored, as well as the difference in transfer between antibodies induced by vaccination and those induced by natural infection, or the influence of maternal factors such as multiple pregnancy, other infections and treatment of these infections. A better identification and understanding of the factors that can affect transplacental transfer of maternal antibodies is crucial for optimization of vaccination strategies and close monitoring of particularly vulnerable newborns.

The investigators aim to include 4050 patients and collect a maternal at delivery cord blood sample.

The aim of the investigators is to measure and compare ratio of transplacental transfer of maternal anti-virus antibodies according to the mode of acquisition of immunity (post-vaccination, or post-natural or mixed infection), gestational age at birth (< 32 Weeks of Gestation -WG-, 32-37 WG and > 37 WG) for several virus (Hepatitis B virus, Varicella zoster virus, Rubella virus, Measles, Influenza Virus, Mumps Virus, SARS-CoV-2, Cytomegalovirus, Herpes Simplex Virus 1 and 2, Respiratory Syncitial Virus, Parvovirus B19, HTLV). The investigators also aim to identify factors likely to influence negatively or positively transplacental transfer of maternal antibodies as maternal age, maternal ethnic origin, parity and gestation, sex of the newborn, maternal chronic or acute infection/disease occurring during pregnancy; Birth weight, vaccine boost carried out during pregnancy (etc.) will also be studied.

Inclusion Criteria:

• Women over 18 years old ;
• Pregnant patient (single or multiple pregnancy) ;
• Gestational age at the time of inclusion > 22 Weeks of Gestation ;
• Patient affiliated or entitled to a french social security scheme ;
• Patient who expressed a non-objection to participate in the study.

Exclusion Criteria:

• Misunderstanding of the French language;
• Participation in another interventional trial of category 1. Participation in category 2 research, with minimal risks and constraints, will be left to the discretion of the investigator;
• Patient under curatorship or guardianship ;
• Patient's refusal to participate in the research.

Pregnant women followed in the Gynecology-Obstetrics department for their pregnancy and/or at the time of their delivery