Using the algorithm of the Fetal Medicine Foundation to determine the cutoff point for prediction of pre-eclampsia in a Brazilian population.

BACKGROUND

To use the algorithm of the Fetal Medicine Foundation (FMF) to determine the cutoff point for prediction of preeclampsia (PE) in a Brazilian population.

METHODS

Randomized clinical trial with 274 nulliparous patients at gestational age between 11 and 13 weeks and 6 days. To calculate the risk of PE, the algorithm available at the website of the FMF (http://fetalmedicine.org/research/assess/preeclampsia/first-trimester) was used. Among the patients, 138 did not use preventive measures (100 mg/day aspirin [ASA]). Youden's criteria were used to calculate the cutoff point. To test the effectiveness of 100 mg/day ASA in preventing PE, the patients were divided into two groups - at risk above and below the cutoff point.

RESULTS

In the group comprising the 135 patients that did not take ASA, the median age was 22 years, the Body Mass Index (BMI) was 59.3 kg/m2, the mean arterial pressure (MAP) was 73.3 mmHg, and the mean pulsatility index of uterine artery Doppler was 1.71. The median gestational age at delivery was 39.3 (38.1-40.3) weeks. The prevalence of PE was 11.1%. In our sample, the use of 100 mg/day ASA reduced total PE by 36.3% (prevalence of PE in the group above the cutoff point was 19% and 12.1% when ASA and placebo were used, respectively).

CONCLUSIONS

The cutoff point defined for prediction of PE was 1:155 with sensitivity of 80%, specificity of 57.5%, positive predictive value of 19.1%, and negative predictive value of 95%, which should help to select patients that will benefit from prophylactic ASA.