PORTO

Small babies in the womb – improved methods to predict those at risk of serious complications, the PORTO Study

Perinatal Ireland, a major HRB-funded research project on improving health outcomes for mothers and babies co-ordinated at the Royal College of Surgeons in Ireland (RCSI), presented new findings which challenge accepted international practice on identifying babies at risk from Intrauterine Growth Restriction (IUGR). The findings were presented at the annual meeting of the Society for Maternal-Fetal Medicine in San Francisco, and published in full in the March edition of the American Journal of Obstetrics & Gynecology.

‘Small babies in the womb (neonates) with IUGR are normally considered those who’s weight falls in the bottom 10%’, says lead researcher Julia Unterscheider (RCSI). ‘The majority of these pregnancies do go on to deliver a healthy normal baby that is simply small for its gestational age. However, some develop serious health complications including a risk of death. And there is recent evidence to suggest that unfavourable intrauterine environments may increase disease risk in adulthood leading to hypertension, diabetes, coronary heart disease and stroke.’

The challenge to distinguish between small but normal babies from small and at-risk babies is one of the most common, controversial and complex problems in modern obstetrics.

Standard international practice has been to consider this bottom 10% by weight to be at the highest risk of developing complications. However this study questions whether this alone really matters? These mothers and babies are usually subject to increased surveillance and monitoring, with questionable benefit.

We found that the highest risk for adverse outcomes were in the group of babies that fell into the bottom 3% by weight and that had an abnormal reading on what is called an umbilical arterial Doppler. This is an ultrasound test that measures arterial blood flow in the umbilical cord. In fact, we found that an abnormal UA Doppler was the strongest and most significant predictor of an increased likelihood of complications.

Our data calls into question whether having a fetus in the bottom 10% by weight along really matters in predicting adverse outcomes. While further work is required to verify our findings, if confirmed, they could lead to a change in clinical practice with a more effective utilisation of resources and potentially improved pregnancy outcomes.’

Between January 2010 and June 2012 the PORTO study (Prospective Observational Trial to Optimise Paediatric Health in IUGR) involved over 1,100 pregnant women at seven maternity hospitals in Ireland. A set of detailed ultrasound measurements were taken at two-weekly intervals, and the baby’s medical status and condition following delivery recorded. The study also collected baseline demographic data on the participants.

See our publications section for PORTO publications.