Antenatal screening of small for gestational age: Impact on obstetrical management and neonatal outcomes in case of trial of labor after 37 weeks.

OBJECTIVE

Antenatal screening of small fetuses for gestational age (SGA) is a public health challenge. The aim of this study is to assess the obstetrical management and the immediate neonatal outcomes, according to the antenatal screening of the SGA fetuses.

METHODS

We performed a retrospective study in a French tertiary care hospital between January 1, 2016 and December 31, 2018. Women were eligible if they had a monofetal pregnancy with a fetus in head presentation and a trial of labor after 37 weeks. A fetus was considered SGA when the estimated fetal weight was less than the 10th percentile at the third trimester ultrasound. A newborn was considered hypotrophic when the birthweight was less than the 10th percentile.

RESULTS

8 153 newborns were included and 948 of the newborns were hypotrophic (308 were suspected for SGA, 640 were not suspected for SGA) and 7205 were eutrophic. Among the hypotrophic neonates, we observed no significant difference regarding the immediate neonatal outcomes between the two groups of fetuses suspected and not suspected for SGA. Among the fetuses not suspected for SGA, the rate of arterial umbilical cord pH below 7.10 was significantly higher in the hypotrophic newborns compared to the non hypotrophic newborns (4.7% vs 3.1%, p = 0.041).

CONCLUSION

In our population, unsuspected fetal hypotrophy may be associated with an increased risk of neonatal acidosis. These results emphasize the benefit of improving prenatal screening to identify the SGA fetuses.