What is bilateral uterine artery notching?

Persistent bilateral notching of uterine artery waveform at 20-24 weeks reflects failed trophoblast invasion of spiral arteries. It is associated with 4-6× increased risk of early-onset preeclampsia and FGR.

What uterine artery PI is abnormal?

Mean uterine artery PI >95th percentile for GA at 20-24 weeks is abnormal. Combined with bilateral notching, LR+ for early preeclampsia is approximately 6-8. First-trimester screening includes MAP, PAPP-A, and uterine artery PI.

How does aspirin reduce preeclampsia risk?

Low-dose aspirin (150 mg nightly, started <16 weeks) reduces early preeclampsia by ~60% in high-risk women identified by first-trimester combined screening (Poon/ASPRE trial). Later initiation or low doses are less effective.

Uterine Artery Notching and PI for Preeclampsia/FGR Risk

Interpret uterine artery Doppler pulsatility index (PI) and bilateral notching at 20-24 weeks for preeclampsia, FGR, and placental abruption risk. Mean PI >95th percentile plus bilateral notching has highest positive predictive value.

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Frequently Asked Questions

What is bilateral uterine artery notching?

What uterine artery PI is abnormal?

How does aspirin reduce preeclampsia risk?