First‐trimester assessment of placenta function and the prediction of preeclampsia and intrauterine growth restriction

Abstract

Preeclampsia and intrauterine growth restriction (IUGR) are major contributors to perinatal mortality and morbidity worldwide. Both are characterized by impaired trophoblastic invasion of the maternal spiral arteries and their conversion from narrow muscular vessels to wide non-muscular channels. Despite improvement in the understanding of the pathophysiology of these conditions, ability to accurately identify pregnant woman who will develop them is limited. This greatly impairs the development and testing of preventive interventions. While different measures of placental dysfunction have been associated with increased risk for adverse pregnancy outcomes, the ability of any single one to accurately predict these outcomes is poor. Developing predictive tests is further challenged by difficulty in the timing of the measurements, as both the structural and biochemical characteristics of the placenta change with increasing gestational age. The ideal screening test would accurately predict the development of adverse pregnancy outcomes early enough to provide a window for preventive interventions. Improvement in ultrasound technology provides potentially useful novel tools for evaluating placental structure, but measuresments need to be standardized in order to be useful. Maternal serum analyte screening is a noninvasive test of placental biochemical function, but present serum marker alone is not sufficiently accurate to suggest its routine use in clinical practice. The use of first trimester biochemical markers in combination with uterine artery Doppler screening is promising as a potential screening tool. Prospective longitudinal studies using standardized methodology are necessary to further evaluate the choice of parameters and strategies of combination to achieve the best predictive models.

Pravastatin improves pregnancy outcomes in obstetric antiphospholipid syndrome refractory to antithrombotic therapy

“…Increased impedance to blood flow in the uterine arteries as shown by a pulsatility index (PI) above the 95th percentile -frequently associated with pregnancy complications associated with defective trophoblast invasion -(36, 37) was observed in all women during Doppler assessment of uteroplacental perfusion (Tables 1 and 2, and Figure 1). Presence of diastolic notching (a characteristic waveform indicating decreased early diastolic flow) in the uterine artery reflects low vessel elasticity (37). Bilateral diastolic notching in uterine arteries was observed in 7 patients.…”

Prediction of Pre-Eclampsia Development by Placenta Location: A Simple Predictor

“…In addition, previous studies have revealed side-to-side differences in uteroplacental Doppler flow in pregnancies with unilateral placentas as well as the relationship between abnormal Doppler measurements and pre-eclampsia (13)(14)(15)(16)(17)(18)(19)(20)(21). However, reports on the direct association between placental location and development of pre-eclampsia, regardless of confounding factors (22), are limited.…”

Utero-placental Doppler ultrasound for improving pregnancy outcome

“…In the attempt to improve the performance of the uterine artery as a screening test, new algorithms that take into account the maternal characteristics, history and/or biochemical markers have been proposed. In fact, uterine artery Doppler in the first and second trimester, in combination with several biochemical markers, has been extensively tested as a predictive test for preeclampsia and IUGR, and the first results are encouraging (Nicolaides 2006;Parra 2005;Plasencia 2007;Spencer 2007;Zhong 2010). Nevertheless, at present the literature comprises several large uncontrolled cohort studies and as yet there are no randomised studies in this field, and the cost-effectiveness remains to be proven.…”