Decreased flow-mediated vasodilation and higher levels of CRP are present in early stages of gestation in women who subsequently develop preeclampsia. These alterations occur before the onset of clinical symptoms of PE. Further studies are needed to confirm that flow-mediated dilation and C-reactive protein could be useful methods to screen women at risk of developing preeclampsia.

Women who subsequently develop PIH have a higher degree of insulin resistance determined by log-HOMA early in pregnancy, before the onset of clinical manifestations of the disease. The HOMA seems to be a useful method to evaluate women at risk of developing PIH. More studies are required to confirm its usefulness as a screening tool to identify pregnant women at risk of developing PIH.

The endothelial release of nitric oxide (NO) has been proposed as the main responsible factor for the decreased systemic vascular resistance observed during pregnancy. In addition, a decreased production or an increased inactivation of NO has been linked to the endothelial dysfunction that characterizes preeclampsia [1]. Flow Mediated Dilatation (FMD), a non-invasive method which uses high resolution ultrasound, is an established test to assess endothelial function, highly dependent on the capacity of endothelial cells to release NO [2]. To evaluate the effect of pregnancy on the endothelial function measured by FMD we sequentially enrolled 492 normotensive Hispanic pregnant women in a prospective cohort study, from March 2001 to March 2005 at the Doppler Ultrasound Department of the Cardiovascular Foundation of Colombia, Bucaramanga. Inclusions criteria were a normal singleton pregnancy with gestational age V 30 weeks and maternal age b 25 years. Fifty-six women were studied in the first trimester, 300 in the middle trimester and 136 during the last trimester. Additionally, 56 young non-pregnant women were recruited from the hospital staff. All subjects gave written informed consent before entering the study. FMD was measured in the brachial artery using a 7.5 MHz transducer (Aloka SSD-2200, Tokyo, Japan) according to previous validated methods [2,3].An increased heart rate was observed in the three groups of pregnant women compared with the non-pregnant group ( p b 0.001). In contrast, systolic blood pressure decreased throughout gestation among pregnant women compared with nonpregnant women ( p b 0.001) ( Table 1). A progressive and significant increase of basal brachial artery diameter was observed throughout pregnancy, with a 10% increase in the artery diameter in the last 0020-7292/$ -see front matter D