As preeclampsia is a disease specially affecting young and primiparous women, and due to the fact that we found previously in several studies a prevalence of 12%, to ensure a confidence of 95% and a power of 80%, it is necessary to include a total of 190 women (95 in each arm), therefore it is planned to recluse a total of 200 pregnant women currently attending to the outpatients clinic at the HGOIA for pregnancy control before than week 20 of gestation.

From each one of those women the clinical research team will obtain an obstetric, anthropometric and clinical record following the current regulations of the Ecuadorian Public Health Ministry. All women included will be under a detailed prenatal control every 4 weeks from week 20 of pregnancy, this will include gestational age, weight, umbilical perimeter, uterine altitude, fetal cardiac frequency and maternal blood pressure.

In addition, in each schedule visit an urine test will be done (to discard proteinuria), also a venous blood sample (10 ml) in heparinized tubes will be taken and immediately transported to the Biomedical Center for centrifugation and plasma isolation. During week 20, all women will be assigned (using a randomized numbers table) to one of the following groups: a) intervention group, that will received two capsules of 100 mg of coenzyme Q10 twice daily up to delivery; or b) control group, that will receive two capsules of the correspondent placebo twice daily up to delivery. Both, active and placebo capsules will be manufactured by the same provider (Jarrow Formulas, Los Angeles, CA, USA) to guarantee that weight, size, odor and color are similar.

Absolutely all women participating in the study will know all contact information of the clinical team and will be allowed to request medical care as frequent as they needed, independently of establish obstetrical controls. Preeclampsia diagnosis will be performed only by clinical researchers and based on a persistent high blood pressure higher than 140/90 mmHg and proteinuria higher than 300 mg/24 hours.

Coenzyme Q10 will be measured using a high performance liquid chromatography equipment (HPLC) and the method previously described and validated by our group.

The hypothesis is that in the group receiving CoQ10 supplementation will be less cases of preeclampsia compared to placebo.