Background Sexually transmitted infections (STI) have been increasing across Europe and have resulted in increasing rates among women of childbearing age.

Methods A retrospective cohort study was performed to derive population-based rates of STIs reported during hospitalisation for delivery between 2005 and 2010 in Ireland. ICD-10-AM codes from hospital discharge records were used to identify STI cases. Due to small numbers, unadjusted relative risks (RR) and corresponding 95% confidence intervals (CI) stratified by age were computed to assess the strength of association between maternal risk factors and STI diagnosis.

Results 415 of 403,642 childbirth hospitalisations included a diagnosis for a STI. Venereal warts were the commonest reported infection (62.4 per 100,000), followed by syphilis (24.3 per 100,000) and anogenital herpesviral infection (13.4 per 10,000). Women aged < 25 years were nearly four times as likely (RR 3.90; 95% CI 3.21–4.74) to have a STI diagnosis at delivery than women aged ≥ 25 years. When stratified by age, relative to married women, single women < 25 years of had a 2-fold risk of having a STI, whereas single women ≥ 25 years of age had 3-fold risk. Over the six-year period, annual syphilis rates ranged from 13.8 to 32.9 per 100,000 maternities. The stillbirth rate was substantially higher in women diagnosed with syphilis.

Conclusions Demographic patterns in STI risk observed from hospital discharge charts were in line with international STI surveillance. The high annual rates of syphilis observed within this well defined, universally screened cohort suggest that syphilis rates are underreported in the general population and underscore the importance of future studies examing congenital syphilis.