A new study which examined Irish maternity hospital data during the recent flu pandemic has affirmed that the seasonal influenza vaccine is safe at any stage during pregnancy.

The research, which was led by RCSI (Royal College of Surgeons in Ireland)'s School of Pharmacy and the Rotunda Hospital, also showed that vaccination uptake was influenced by sociodemographic factors such as age and country of origin of the mother.

The research has been published in the European Journal of Obstetrics & Gynecology and Reproductive Biology. 

Vaccination uptake was found to be less likely in younger age groups; those who were not in the professional/ manager/employer socioeconomic group; women from Eastern Europe, Africa and Asia/Middle East; those who reported an unplanned pregnancy; women who booked late for antenatal care; and recipients of publicly-funded obstetric care. Irish nationality was associated with reporting vaccination.

There was no association between vaccination during pregnancy and adverse pregnancy outcomes. Women who were vaccinated were less likely to have a preterm delivery than unvaccinated women.

Lead author on the study Professor Brian Cleary, Chief Pharmacist, Rotunda Hospital and Honorary Clinical Associate Professor, RCSI School of Pharmacy said: "Our study further provides further reassurance to pregnant women on the safety of flu vaccination in pregnancy. Our findings support current recommendations from the Health Protection Surveillance Centre for all pregnant women to be vaccinated against seasonal influenza at any stage during pregnancy."

"Future public health campaigns should provide clear information on vaccination safety in pregnancy, ensure consistent vaccination recommendations from healthcare professionals and provide easy access to vaccination in order to encourage uptake in cohorts of the population who less likely to be vaccinated," Professor Cleary concluded.

The study was carried out using electronic records from the Coombe Women and Infants University Hospital, Dublin, Ireland. Women who were pregnant with a single baby before (December 2008-September 2009) and during the A/H1N1 pandemic (December 2009-September 2010) were included. Pregnancy outcomes were compared for vaccinated and unvaccinated women, with adjustment for differing maternal characteristics. Outcomes included vaccination status, preterm birth, size for gestational age, neonatal intensive care admission, congenital anomalies and perinatal death.

Of 6,894 women pregnant during the pandemic, 43.5% reported vaccination at delivery. In the early weeks of the vaccination programme rates of over 70% were achieved. Of those vaccinated, 8.2%, 57% and 34.5% were vaccinated in the first, second and third trimesters respectively.

Co-authors on the study were Ms Úna Rice, Pharmacy Department, Coombe Women and Infants University Hospital; Dr Maeve Eogan, Rotunda Hospital; Dr Nehad Metwally, Discipline of Paediatrics, School of Medicine, Trinity College Dublin; and Professor Fionnuala McAuliffe, National Maternity Hospital and Department of Obstetrics and Gynaecology, School of Medicine and Medical Science, University College Dublin.