New findings by Perinatal Ireland, a HRB-funded initiative to improve health outcomes for mothers and babies, are challenging currently accepted international practice in relation to identifying which babies are at risk from growth restrictions in the womb, medically referred to as Intrauterine Growth Restriction or IUGR.

Lead researchers from Perinatal Ireland, which is coordinated by RCSI, will present their discovery at the annual meeting of the Society for Maternal Fetal Medicine in San Francisco.

“The challenge to distinguish small but normal babies from small at-risk babies, is one of the most common, controversial and complex problems in modern obstetrics,” says lead researcher Julia Unterscheider, at RCSI.

“Standard international practice has been to consider those babies in the bottom 10% by weight to be at the highest risk of developing complications. These mothers and babies usually receive increased surveillance and monitoring. However, our study questions whether this is necessary for all cases.”

The majority of babies whose weight falls into the bottom 10% from a weight perspective go on to be a healthy baby that is simply small for its gestational age. However, some develop serious health complications, and possibly even die. And there is recent evidence to suggest that unfavourable conditions in the womb may increase risk of diseases in adulthood such as hypertension, diabetes, coronary heart disease and stroke. So it is believed that close monitoring of this 10% is necessary.

“However, we conducted a study involving over 1,100 pregnant women at seven maternity hospitals across Ireland using state-of-the-art ultrasound equipment supplied by the Health Research Board (HRB), which allow very detailed monitoring of babies in the womb. We took a set of in-depth ultrasound measurements normally at two-weekly intervals, or more frequent if deemed appropriate, and recorded the baby's medical status and condition following delivery.”

The findings revealed that the highest risk for adverse outcomes are in the group of babies that fall into the bottom 3% by weight and who have an abnormal reading on the ultrasound test that measures arterial blood flow in the umbilical cord.

“In fact, the measurement of blood flow in the umbilical cord was the strongest and most significant predictor of an increased likelihood of complications,” explains Dr Unterscheider. “Our data calls into question whether monitoring all of those in the bottom 10% by weight alone is necessary when predicting adverse outcomes.”

Prof. Fergal Malone, RCSI Department of Obstetrics & Gynaecology and Chairman of the Perinatal Ireland Research Consortium commented; “The major benefit of this study is the potential to radically change the focus and intensity of current assessment for the apparently small baby in the womb.”