[Risk factors in pre-eclampsia]

PATIENT-RELATED FACTORS: Multiparous patients with a past history of severe pre-eclampsia are a high risk population which should be identified early in pregnancy. Selection on this criterion alone is however insufficient for large scale screening and prevention because most of the susceptible women are nulliparous. Search for a particular familial or personal history of vascular disorders can be helpful. The usefulness of blood pressure measurements during the second trimester has not been proven.

There is a significant association between pre-eclampsia and a large number of biological markers. No one assay can however fulfill the requirements for effective early screening because sensitivity is too low or the rate of false positives is too high, or because the examination is too invasive or costly.

Doppler exploration of the uterine arteries at 20 to 24 weeks gestation offers satisfactory sensitivity and specificity but the positive predictive value is low. Persistence of a bilateral notch beyond 24 weeks considerably limits the number of false positives. More than half of the patients with this anomaly will develop hypertension during pregnancy. While no one marker fulfills all the prerequisites for effective screening, a combination of several tests may be useful. hCG assay during the second trimester in association with Doppler exploration of the uterine arteries appears to be a promising combination.

Starting with these markers or risk factors, the goal is to develop a prevention scheme using low-dose aspirin, the only evidence-based preventive treatment to date. Further trials are required to test simultaneously the predictive value and impact (versus placebo) of proposed strategies.