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Updated: May 3, 2026
Fetal Echocardiography and Pulsed-wave Doppler Ultrasound in a Rabbit Model of Intrauterine Growth Restriction
Published on: June 29, 2013
Fetal growth restriction and the risk of perinatal mortality-case studies from the multicentre PORTO study
Julia Unterscheider1, Keelin O'Donoghue, Sean Daly
1Obstetrics & Gynaecology, Royal College of Surgeons in Ireland, Dublin, Ireland. juliaunterscheider@rcsi.ie.
Insights
Intrauterine growth restriction (IUGR) poses a high risk for perinatal death. Increased surveillance and timely delivery in identified IUGR cases, as seen in the PORTO study, can improve outcomes, though not all deaths are preventable.
Area of Science:
- Perinatal Medicine
- Fetal Medicine
- Obstetrics
Background:
- Intrauterine growth restriction (IUGR) is a major cause of perinatal mortality in non-anomalous fetuses.
- Stillbirth rates have remained unchanged despite advances in neonatal care.
- Antenatal detection of fetal growth restriction is challenging and associated with high perinatal risk.
Purpose of the Study:
- To analyze perinatal outcomes in a cohort of pregnancies with identified intrauterine growth restriction (IUGR).
- To investigate factors associated with perinatal mortality in IUGR cases.
- To evaluate the effectiveness of increased surveillance and timely delivery in reducing IUGR-related deaths.
Main Methods:
- The Prospective Observational Trial to Optimize Paediatric Health in IUGR (PORTO) study recruited 1,200 singleton pregnancies with estimated fetal weight (EFW) <10th centile.
- Serial sonographic assessments and multi-vessel Doppler studies were conducted.
- Perinatal outcomes of deaths within the cohort were reviewed and analyzed.
Main Results:
- A perinatal mortality rate (PNMR) of 5.4/1,000 was observed in 1,116 non-anomalous singleton infants with EFW <10th centile.
- Perinatal deaths were more frequent in cases of severe growth restriction (EFW <3rd centile) with abnormal Doppler findings.
- Maternal comorbidities, adverse obstetric history, non-Irish ethnicity, and placental abnormalities were associated with perinatal deaths.
Conclusions:
- The PNMR in this prenatally identified IUGR cohort suggests improved outcomes due to enhanced surveillance and timely delivery.
- Despite antenatal recognition and management, not all perinatal deaths in IUGR pregnancies can be prevented.
- Placental histopathology is crucial in understanding the mechanisms of IUGR-related perinatal death.
Background:
Intrauterine growth restriction (IUGR) is the single largest contributing factor to perinatal mortality in non-anomalous fetuses. Advances in antenatal and neonatal critical care have resulted in a reduction in neonatal deaths over the past decades, while stillbirth rates have remained unchanged. Antenatal detection rates of fetal growth failure are low, and these pregnancies carry a high risk of perinatal death.
Methods:
The Prospective Observational Trial to Optimize Paediatric Health in IUGR (PORTO) Study recruited 1,200 ultrasound-dated singleton IUGR pregnancies, defined as EFW <10th centile, between 24+0 and 36+6 weeks gestation. All recruited fetuses underwent serial sonographic assessment of fetal weight and multi-vessel Doppler studies until birth. Perinatal outcomes were recorded for all pregnancies. Case records of the perinatal deaths from this prospectively recruited IUGR cohort were reviewed, their pregnancy details and outcome were analysed descriptively and compared to the entire cohort.
Results:
Of 1,116 non-anomalous singleton infants with EFW <10th centile, 6 resulted in perinatal deaths including 3 stillbirths and 3 early neonatal deaths. Perinatal deaths occurred between 24+6 and 35+0 weeks gestation corresponding to birthweights ranging from 460 to 2260 grams. Perinatal deaths occurred more commonly in pregnancies with severe growth restriction (EFW <3rd centile) and associated abnormal Doppler findings resulting in earlier gestational ages at delivery and lower birthweights. All of the described pregnancies were complicated by either significant maternal comorbidities, e.g. hypertension, systemic lupus erythematosus (SLE) or diabetes, or poor obstetric histories, e.g. prior perinatal death, mid-trimester or recurrent pregnancy loss. Five of the 6 mortalities occurred in women of non-Irish ethnic backgrounds. All perinatal deaths showed abnormalities on placental histopathological evaluation.
Conclusions:
The PNMR in this cohort of prenatally identified IUGR cases was 5.4/1,000 and compares favourably to the overall national rate of 4.1/1,000 births, which can be attributed to increased surveillance and timely delivery. Despite antenatal recognition of IUGR and associated maternal risk factors, not all perinatal deaths can be prevented.
