Dynamic of abnormal uterine perfusion during pregnancy and perinatal outcome

Objective: Abnormal uterine perfusion in second trimester is a risk indicator regarding preeclampsia and IUGR. During ongoing pregnancy uterine perfusion often improves or even normalizes. This study analyses how far perinatal outcome is influenced by this dynamic.

Methods: 137 second trimester pregnancies (week 18 to 26) were included in this retrospective study. All patients were characterized by an abnormal uterine perfusion (mean pulsatility index of both uterine arteries >1.4 and/or bilateral notching). A second doppler examination was performed 4 weeks later and/or following clinical necessity.

Results: 35.7% of all patients already showed a normalization of uterine perfusion between the two measurements (week 21 to 32). In patients with persistent abnormal uterine perfusion (64.3%) subsequent complications were significantly more often (22% vs. 60.5%, p<0.001). This was mainly due to a significantly higher rate of preeclampsia (4.7% vs. 23.5%, p<0.01), IUGR (13.3 vs. 42%, p<0.01), and preterm delivery before 37 weeks of gestation (20% vs. 42%, p<0.025).

Conclusion: The dynamic of a primarily abnormal uterine perfusion gives important prognostic information for the later course of pregnancy. A normalization of uterine perfusion is associated with a significantly lower risk of abnormal pregnancy outcome and thus represents a positive prognostic criterion. We conclude that in the case of an abnormal uterine perfusion in the second trimester a follow-up measurement is needed.