Background Perinatal mortality is a significant measurement of the outcome of obstetric and neonatal care. For this reason, in 2011, the National Perinatal Epidemiology Centre (NPEC) established the first national clinical audit of perinatal mortality in Ireland.

Methods Anonymised data on perinatal deaths that occurred between January 1 and 31 December 2016 were collected by contributors from each of the 19 maternity units in Ireland using a validated and standardised notification form. National rates per 1,000 births and corresponding 95% confidence intervals were calculated. Customised birthweight centiles were calculated for all perinatal deaths using the Gestational Related Optimal Weight (GROW) software.

Results Based on the criteria of birthweight ≥500 g or gestation at delivery ≥24 weeks, in total in 2016, 374 deaths were reported to the NPEC, of which 250 were stillbirths and 124 were early neonatal deaths. Stillbirth, early neonatal and perinatal mortality rates (PMR) were 3.9, 1.9 and 5.8 per 1,000 births respectively. The PMR corrected for congenital malformation was 3.6 per 1,000 births. Maternal factors such as advanced age and increased body mass index (BMI) were found to be associated with increased perinatal mortality. Major congenital anomaly was the primary cause of death in both stillbirths (n=78/250, 31.2%) and early neonatal deaths (n=68/124, 54.8%). The use of customised birthweight centiles showed that fetal growth restriction (FGR) was common. In cases of stillbirths, 60.0% of all stillbirths were classified as small for gestational age (SGA) (<10th customised birthweight centile) and 47.2% were severely SGA (<3rd customised birthweight centile) compared to 33.9% and 25.0% of the cases of early neonatal deaths. Although the use of customised birthweight centiles showed that FGR occurred frequently, an antenatal diagnosis of FGR was only made in less than one in five (19%, n=69 of 363, unknown for 11 cases) of perinatal deaths.

Discussion Clinical audit of perinatal outcomes in all maternity units in Ireland is vital for monitoring and improving patient care. Major congenital anomaly remains the main cause of death in stillbirths and early neonatal deaths. FGR continues to appear as a significant associated factor with perinatal mortality. Improved antenatal detection is a potentially modifiable factor. As recommended by the Institute of Obstetrics and Gynaecology, second trimester fetal anomaly ultrasound scanning should be universally available for all pregnant women in Ireland. A public health education programme on perinatal deaths and modifiable risk factors should be developed.