Impaired placentation in women with chronic hypertension who develop pre-eclampsia

Objective: To compare the degree of impaired placentation in pregnancies which develop preeclampsia (PE) in women with and without chronic hypertension (CH).<br /><br />Methods: The data for this study were derived from prospective screening for adverse pregnancy outcomes in women with singleton pregnancies attending for their first routine hospital visit at 11+0-13+6 weeks’ gestation. This visit included recording of maternal characteristics and medical history and measurements of mean arterial pressure (MAP),<br />uterine artery pulsatility index (UTPI), serum placental growth factor (PLGF) and serum pregnancy associated plasma protein-A (PAPP-A). The measured biomarkers were converted to multiples of the median (MoM) after adjustment for pregnancy<br />characteristics and MoM values in women with CH that developed PE (n=283) were compared to those of women without CH that developed PE (n=2,236).<br /><br />Results: In both groups with and without CH the measurements of MAP and UTPI were increased, whereas those of PLGF and PAPP-A were decreased and the deviation from normal in all biomarkers decreased with advancing gestational age at delivery with PE. There was no significant difference between those with and without CH in the slope of the regression line of Log10 MoM biomarker values with gestational age at delivery with PE for any of the biomarkers. However, there was a significant difference in the intercepts and coefficients of biomarkers in the two groups; in the CH group, compared to those without CH, the MAP MoM was higher (p<0.0001), UTPI MoM was lower (p=0.004), placental growth factor MoM was higher (p=0.001) and PAPP-A MoM was higher (p=0.015).<br /><br />Conclusion: In pregnancies that develop PE the degree of impaired placentation, reflected in high UTPI and low PLGF and PAPP-A at 11-13 weeks’ gestation, is less in women with than without CH.