(1112) Factors associated with latency duration in growth-restricted fetuses with absent end diastolic flow

Gestational latency after findings of abnormal umbilical artery doppler indices, such as absent end diastolic flow (AEDF), in the setting of fetal growth restriction (FGR), is important yet difficult to predict. Our objective was to describe latency and factors associated with prolonged latency in growth-restricted fetuses with AEDF. 

Study Design:

This retrospective cohort study from a single large institution (2020-2022) included pregnant people with a non-anomalous singleton fetus with FGR and AEDF who had a mid-trimester anatomy ultrasound documented within our system and delivered at our institution. We compared demographic, obstetric, and ultrasonographic factors associated with latency duration ( >14 days [short] to ≤14 days [long]), which was defined as time from diagnosis of  AEDF, including either intermittent AEDF or persistent AEDF, to delivery.

Results:

Fifty-four pregnant people met inclusion criteria, including 28 (52%) with a latency of ≥14 days. The median latency duration for the total population was 16.5 days (36 [IQR 22-55] days in long vs. 3 [IQR 2-5] days in short). Demographic and obstetric characteristics did not differ between the two groups (Table 1). Pregnant people with a long latency were diagnosed with FGR at an earlier gestational age (GA) (23.5 [IQR 20.4-27.1] weeks vs. 29.6 [IQR 22.2-32.1] weeks) and were found to have AEDF at an earlier GA (27.5 [IQR 25.1-29.3] weeks vs. 30.5 [IQR 26.3-33.1] weeks). They were also more likely to either have improvement in their UA dopplers on subsequent ultrasounds or to progress to reversed end diastolic flow. Gestational age at delivery was similar between the two groups (32.3 [IQR 29.4-36.4] weeks vs. 31.1 [IQR 27.4-33.4] weeks).

Conclusion:

Earlier GA at diagnosis of FGR and earlier progression to AEDF were associated with longer latency, resulting in similar gestational age at delivery for both groups. This inverse relationship between GA at diagnosis of doppler abnormalities and latency duration suggests a more optimistic outlook for pregnancies affected by early-onset doppler abnormalities.