Antepartum risk score predicts adverse birth outcomes

Abstract

Objective: Standardized risk assessment plays an important role in providing medical care of uniform quality to pregnant women, even though it is not a substitute for clinical judgement. This study was designed to determine whether the antepartum risk score currently used across Alberta is associated with neonatal morbidity and adverse pregnancy outcomes for singleton live births and to examine whether the current classification of "lower risk" pregnancies (score < 3) is justified.

Methods: A retrospective study was conducted of the delivery records for a cohort of all live singleton births in Alberta from 2001 to 2005 that contained a completed antenatal risk assessment. Adverse neonatal condition or pregnancy outcome was assessed by Apgar score, transfer of the infant to a neonatal intensive care unit, "serious" resuscitation measures, preterm birth, and low birth weight. The population-attributable fraction of any of the adverse outcomes was calculated.

Results: All outcome measures except for NICU admissions were available for the entire 2001 to 2005 period (n = 191,686); NICU admissions were consistently recorded only from 2002 to 2005 (n = 154,924). The incidence of complications increased steadily as the risk score increased and increased more steeply above a score of 4. Approximately one third of the complications were associated with risk scores of between 2 and 6.

Conclusion: The antepartum risk score currently used in Alberta is a useful tool for identifying women at higher risk of an adverse pregnancy outcome. Current categorization of pregnancies with an antepartum risk score of 2 as lower risk should be reconsidered in light of these findings.