Читать книгу Protocols for High-Risk Pregnancies - Группа авторов - Страница 74

There has been considerable effort over the past two decades with the application of maternal Doppler studies of the uterine arteries in the prediction of adverse pregnancy outcomes including preeclampsia, FGR, fetal demise, and preterm birth. The most distal branches of the uterine artery (spiral arteries) undergo a remarkable transition during the first half of pregnancy, from highly muscularized vessels with high resistance to remodeled vessels with low resistance. This is in response to differentiation of cytotrophoblast to noninvasive and invasive cytotrophoblast, with the latter literally invading and altering spiral artery muscular architecture. It is this change that leads to the enormous blood flow eventually seen in pregnancy (600–800 mL/min).

There are many publications on the use of uterine artery Doppler for predicting adverse pregnancy outcomes in both low‐risk and high‐risk populations. In the low‐risk population, there does not seem to be a benefit of wide application of this Doppler test as a screening tool for adverse pregnancy events. There may be a role in uterine artery Doppler testing in high‐risk pregnancy as it may identify a subgroup of patients at a higher risk for adverse events, which may lead to useful additional monitoring during pregnancy or preventive strategies. In addition, the high negative predictive value for adverse pregnancy events can provide reassurance. However, before this test can be applied to the general or even the high‐risk pregnancy population, further evidence is needed to elucidate a clear predictive capability, the optimum gestational age for screening, standardization for study technique and abnormal test criteria, and an effective prevention therapy or strategy; this position has been supported by the Society for Maternal‐Fetal Medicine.