. 2018 Feb 1;2018(2):CD001269. doi: 10.1002/14651858.CD001269.pub6

pcb Trotta 2014.

Methods	Retrospective cohort study
Participants	Women residing in the Lombardy region, aged at least 12 and up to 55 years (n = 86,171), whose delivery took place between 23 and 45 weeks of gestation between 1 October 2009 and 30 September 2010, in public or private institutions as well as at home, identified through the regional birth registry (stillbirths were included if the gestational age exceeded 180 days)
Interventions	MF‐59 adjuvanted pandemic H1N1 vaccine. 6426 women received the vaccine during pregnancy.
Outcomes	Pregnancy complication pre‐eclampsia/eclampsia, gestational diabetes in‐hospital maternal death (deaths during labour or delivery occurring in a healthcare institution) admission to intensive care unit type of delivery Perinatal death stillbirth (delivery of a dead foetus after 180 days of amenorrhoea) in‐hospital neonatal death Neonatal outcomes small for gestational age neonates (< 10th centile) admission to NICU neonatal reanimation composite outcome: presence of any of the following: clinical information/diagnoses: very low 5‐minute Apgar score (≤ 3), acute respiratory distress syndrome, asphyxia, intraventricular haemorrhage, and acute necrotising enterocolitis congenital malformations including: nervous system, eye, ear, face, and neck, congenital heart defects, respiratory, orofacial clefts, digestive system, abdominal wall defects, urinary, genital, limb, others. Diagnosis with a code compatible to to ICD‐9 in either the medical birth registry or the hospital discharge, according to EUROCAT guideline
Notes	Funding source ‐ government Funding: Only public employees of the national or regional health authorities were involved in conceiving, planning, and conducting the study; no additional funding was received.
*Risk of bias*
Bias	Authors' judgement	Support for judgement
PCS/RCS ‐ selection exposed cohort   All outcomes	Low risk	All mothers with singleton pregnancy between 1 October 2009 and 30 September 2010 in the Italian region of Lombardia
PCS/RCS ‐ selection non‐exposed cohort   All outcomes	Low risk	From the same population as the exposed cohort
PCS/RCS ‐ comparability   All outcomes	Low risk	Possible confounders have been taken into account.
PCS/RCS ‐ assessment of outcome   All outcomes	Low risk	Hospital records
Summary assessment	Low risk	Low risk of bias

AE = adverse event  ARI = acute respiratory illness  ATP = according to protocol  CCA = chicken erythrocyte agglutination  CCI = culture‐confirmed influenza illness  CCIV = cell culture‐derived inactivated flu vaccine  CDC = Centers for Disease Control and Prevention  CI = confidence interval  DFA = direct fluorescent antibody  ECG = electrocardiogram  FEF = forced expiratory flow  FEV1 = forced expiratory volume in one second  FVC = forced vital capacity  GBS = Guillain‐Barré syndrome  GMT = geometrical mean titre  GP = general practitioner  GSK = GlaxoSmithKline  HA = haemagglutinin  HA0 = full‐length uncleaved haemagglutinin  HI = haemagglutination inhibition  HMO = health maintenance organisation  ICD = International Classification of Diseases  IgA = immunoglobulin A  ILI = influenza‐like illness  ITI = intention‐to‐immunise  ITT = intention‐to‐treat  IM = intramuscular  IN = intranasal  IU = international units  KP = Kaiser Permanente  KSC = Kelsey‐Seybold Clinic  LAIV = live attenuated influenza vaccine  LCI = laboratory‐confirmed influenza  LMP = last menstrual period  MAE = medical attended event  MCO = managed care organisation  MDCK = Madin‐Darby canine kidney cells  MS = multiple sclerosis  NCKPHP = Northern California Kaiser Permanente Health Plan  NICU = neonatal intensive care unit  OMP = outer membrane protein  OR = odds ratio  ORS = oculo‐respiratory syndrome  PCA = primary cardiac arrest  PCR = polymerase chain reaction  PCS/RCS = prospective/retrospective cohort study  pfu = plaque‐forming units  PP = per‐protocol  RCT = randomised controlled trial  rHA0 = recombinant uncleaved haemagglutinin glycoprotein  RhMK = rhesus macaque kidney cells  RT‐PCR = reverse transcription polymerase chain reaction  SAE = serious adverse event  SAS = statistical analysis systems  TIV = trivalent inactivated vaccine  URTI = upper respiratory tract infection  VMCCI = vaccine‐matched, culture‐confirmed influenza  WDL = working days lost  WHO = World Health Organization  WRL = Wellcome Research Laboratories (Beckenham, Kent)