The role of second trimester uterine artery doppler using uterine artery score in routine prenatal care in Switzerland

Abstract

Objective

The role of 2nd trimester uterine artery Doppler (UtAd) remains unclear and its implementation varies greatly. Aim of this study was to determine whether 2nd trimester UtAd interpreted with uterine artery score (UAS), a score combining PI and notching in both UtA, is useful in an unselected population in routine care.

Methods

We retrospectively calculated the UAS in 503 unselected singleton pregnancies with 2nd trimester scan at 20–24 weeks between 09/2021 and 08/2023 and later delivery in our department and analysed its relationship with perinatal outcome.

Results

With UAS > 2 there was a significant increase in adverse perinatal outcome such as hypertension/PE (OR 7.88), SGA (OR 6.82), preterm birth (OR 5.51) and placental abruption (OR 6.89). In contrast, no significant difference was found when comparing UAS 0, 1 and 2. In general, NPV for adverse outcomes were high while PPV were low. In 50 % of SGA-fetuses and 33 % of cases with hypertension/PE in UAS 3–4, the woman had no risk factor.

Conclusion

Routine 2nd trimester UtAd is useful in all pregnancies as it can identify additional patients without a pre-existing risk who generally would not be eligible for intense surveillance but still develop PE or SGA later. Further, due to the high NPV, UtAd qualifies as a rule-out tool for adverse outcome even in high-risk pregnancies. To standardise its interpretation, UAS with a cut-off at 2 seems to be a suitable tool for an unselected population. In case of UAS 3–4 a more intense surveillance program should be offered.