Objective: To compare urinary placental growth factor (PlGF) concentration at 11(+0) to 13(+6) weeks of gestation in women who subsequently develop pre-eclampsia with normotensive controls.
Design: Nested case-control study within a prospective study for first trimester prediction of pre-eclampsia.
Setting: Routine antenatal visit in a teaching hospital.
Population: Fifty-two women who developed pre-eclampsia and 52 controls matched for gestational age and sample storage time.
Methods: Urinary PlGF concentration and PlGF to creatinine ratio were measured in women who developed pre-eclampsia and their matched controls. Comparisons between groups were performed using Student's t test.
Main outcome measures: Development of pre-eclampsia.
Results: In the pre-eclampsia group, the median urinary PlGF concentration (20.6 pg/ml, interquartile range [IQR] 9.1-32.0 pg/ml) and median urinary PlGF to creatinine ratio (1.6 pg/mg, IQR 1.2-2.5 pg/mg) were not significantly different from the control group (11.8 pg/ml, IQR 5.5-29.8 pg/ml, P=0.1 and 1.7 pg/mg, IQR 1.2-2.3 pg/mg, P=0.3, respectively). There were no significant differences between women with early-onset pre-eclampsia requiring delivery before 34 weeks (n=13) and those with late-onset pre-eclampsia (n=39) and between women with pre-eclampsia and fetal growth restriction (FGR) (n=25) and those with pre-eclampsia and no FGR (n=27) in either median PlGF concentration or median urinary PlGF to creatinine ratio.
Conclusions: The development of pre-eclampsia is not preceded by altered urinary PlGF concentration in the first trimester of pregnancy.