The investigators will conduct a monocentric , prospective, observational study, including 300 pregnant women (150 normotensive and 150 preeclamptic).
The participants will be divided into 2 equal groups :
* Group P : Preclampsia
* Group N : Normotensive
After written and informed consent are obtained, a standard battery of blood tests including serum BH4 will be runned for the eligible patients at any moment from the admission to the end of the pregnancy.
Baseline data will be collected at enrollment, including demographic and medical history information, blood pressure, proteinuria, and blood samples for BH4 and other biomarker measurements. Follow-up data will be collected at delivery, including blood pressure, proteinuria, and fetal growth measurements, as well as maternal and neonatal outcomes;
After collecting all groups, blood samples will be analysed for BH4.
