Late normalisation of uterine artery velocimetry in high risk pregnancy.

OBJECTIVE

To test whether late normalisation of abnormal uterine velocimetry is a favourable prognostic factor in high risk pregnancies.

STUDY DESIGN

Uterine artery colour Doppler velocimetry was performed at 24, 28-30 and 32-34 weeks in 282 high risk pregnancies treated with low dose aspirin.

RESULTS

88 patients had abnormal waveforms at 24 weeks and 77 delivered after the second assessment at 28 weeks. Of these, 38 (49%) had a normalisation of Doppler indices by 34 weeks. Compared with the persistently abnormal Doppler group, these patients delivered fewer small for gestational age babies (5/38 versus 26/39; p=0.0001) and had less gestational hypertension without proteinuria (3/38 versus 15/39; p=0.004). No patients with preeclampsia or other severe complications of pregnancy were observed in the normalised group.

CONCLUSIONS

Although abnormal uterine artery velocimetry at 24 weeks is predictive of adverse pregnancy outcome, nearly half have late normalisation of the Doppler indices and a better perinatal outcome. Persistently abnormal waveforms are related to the worst pregnancy outcome.