pcb Beau 2014.

Methods	Retrospective cohort study. Pregnancies ending between 21 October 2009 (the start of the vaccination campaign) and 30 November 2010 and that had started before 31 January 2010 identified using databases EFEMERIS (database including pregnant women) and CNAMTS (vaccination database): 1645 women exposed to A/H1N1 vaccine during pregnancy and 3290 randomly selected who did not receive A/H1N1 (matched for month and year of the start of pregnancy)
Participants	Data about study population come from an extended database (EFEMERIS) collecting and linking information from 4 different sources: CPAM (Caisse Primaire d’Assurance Maladie), the French Health Insurance System of Haute‐Garonne (South West France): it records all the reimbursed drugs prescribed and dispensed to patients under general state coverage (classified according to the World Health Organization’s Anatomical Therapeutic Chemical classification); PMI (Protection Maternelle et Infantile), the Mother and Child Protection Center: it contains data about the health of both mother (maternal characteristics, some pathologies during pregnancy) and child (weight, size, Apgar score, neonatal pathologies, psychomotor development, congenital malformations) collected during the compulsory medical examinations at ages 8 days, 9 months and 2 years; CDA (Centre de Diagnostic Anténatal), the Antenatal Diagnosis Center centralises data corresponding to all the occurrences of major and minor malformations in the maternities of the region where therapeutic termination has been considered (cause and date of termination); PMSI (Programme de médicalisation des systèmes d’information), the French hospital medical information system provides the nature and date of termination (legal termination, stillbirth, and spontaneous abortion) from Toulouse University Hospital Center. EFEMERIS contains information about 58,171 mother‐outcome pairs with women who delivered in Haute‐Garonne between 1 July 2004 and 31 December 2010. For the present study, only pregnancies ending between 21 October 2009 (the start of the vaccination campaign) and 30 November 2010 (9 months after the vaccination centres had closed) and that had started before 31 January 2010 were considered (n = 12,120). For each mother‐outcome pair exposed to A/H1N1 vaccine during pregnancy (n = 1645), 2 mother‐outcome pairs were randomly selected from among individuals in the study population who did not receive A/H1N1 vaccine during pregnancy but who were matched for month and year of the start of pregnancy (n = 3290).
Interventions	Exposure to monovalent pandemic H1N1 vaccine during pregnancy. Vaccination centres were required to report A/H1N1 vaccinations to the French National Health Insurance Fund for Salaried Workers (Caisse National de l’Assurance Maladie des Travailleurs Salariés; CNAMTS) Exposure was considered at any time during pregnancy. For neonatal pathologies, a subset of babies born from mothers who were immunised within the 3rd pregnancy trimester was also considered. Authors report that 93% of the exposed women received the non‐adjuvanted Panenza (Sanofi Pasteur), but did not provide any further details.
Outcomes	All‐cause pregnancy loss: any loss occurring during pregnancy (legal and therapeutic termination, spontaneous abortion, stillbirth, and ectopic pregnancy). Preterm delivery: birth before 259 days of amenorrhoea/37 completed weeks. Small for gestational age: any singleton with a birth weight < 2 standard deviations from the French reference weight mean, adjusted for gestational age and sex. Neonatal pathologies (including respiratory distress, pneumothorax, neonatal jaundice, metabolic disorders, or sepsis): identified from the children’s health certificates established on the 8th day, as recorded by the physician during medical consultation; these records provided little detail about the conditions.
Notes	Funding source ‐ government “The EFEMERIS database was funded by the Agence Nationale de Sécurité du Médicament et des produits de santé (ANSM), the CNAMTS, the Mutuelle Générale de l’Education Nationale, the Clinical Research Hospital Program (PHRC) and the Unions régionales des Caisses d’Assurance Maladie. Additional funding has been received from the ANSM for the influenza medication study”
Risk of bias
Bias	Authors' judgement	Support for judgement
PCS/RCS ‐ selection exposed cohort All outcomes	Low risk	The whole cohort of pregnant women between October 2009 and November 2010 was considered. Those who were vaccinated were the exposed cohort.
PCS/RCS ‐ selection non‐exposed cohort All outcomes	Low risk	Drawn from the same source as the exposed cohort
PCS/RCS ‐ comparability All outcomes	Low risk	Possible confounding factors have been taken into account in data analysis (adjustment).
PCS/RCS ‐ assessment of outcome All outcomes	Low risk	Secure records
Summary assessment	Low risk	Low risk of bias