Table 1.

Characteristics of studies assessing sFlt-1 in first trimester of pregnancy

Reference	Location	Study Design	Type of sample and gestational age at screening	Participants	Outcome(s)	s-FLT1 Summary measure
Akolekar, 2010	United Kingdom	nested case-control	Plasma 11-13 weeks	Singleton pregnancies Exclusions: hypertension but uncertainty about a diagnosis of preeclampsia (n = 30), preeclampsia but stored blood not available (n = 57)	Preeclampsia < 34 weeks ≥ 34 weeks	median
Baumann, 2008	Switzerland	case-control	Serum 11-14 weeks	Singleton pregnancies Exclusions: women with history of hypertensive disorders, immunological diseases, HELLP, or PE < 34 weeks	Preeclampsia	mean, median
Chaiworapongsa, 2005	Chile	case-control	Plasma 7-16 weeks	Singleton pregnancies. Exclusions: pregnancies with fetal anomaly or demise, vaginal bleeding, women with serious medical conditions, chronic hypertension, asthma requiring medication, or requiring the use of anti-platelet or non-steroidal anti-inflammatory drug.	Preeclampsia	mean
Erez, 2008	Chile	nested case-control	Plasma 6-15 weeks	Singleton pregnancies.	SGA, Preeclampsia (preterm and term)	median, OR
Eskild, 2008	Norway	nested case-control	Serum 4-12 weeks	Normotensive pregnant women only.	Excessive postpartum bleeding	mean
Lynch 2010	USA 2005-2008	prospective cohort	Serum 10-15 weeks	Singleton pregnancies, women presenting for prenatal care Exclusions: intrauterine fetal loss, gestational hypertension	Preeclampsia	mean
Noori 2010	United Kingdom	prospective cohort	Serum 10-17 weeks	Singleton pregnancies from routine screening (n = 114) and an obstetric medicine clinic (n = 45)	Preeclampsia, (preterm and term) Gestational hypertension	geometric mean
Rana S, 2007	USA, 2001-2003	nested case-control	Serum 11-13 weeks	Singleton pregnancies delivered > 20 weeks (livebirths) gestation. Exclusions: women with history of hypertension, hypertension 6 weeks postpartum, renal disease, or diabetes.	Preeclampsia,	mean
Smith, 2007	Scotland, 1997-99	nested case-control	Serum 10-14 weeks	Singleton pregnancies. Exclusions: stillbirths due to congenital anomalies or rhesus disease.	Preeclampsia SGA Preterm (extreme and moderate) Stillbirth	OR
Thadhani R, 2004	USA, 2001-2003	nested case-control	Serum 8-14 weeks	Singleton pregnancies > 20 weeks gestation. Exclusions: women with hypertension > 6 weeks postpartum, history of thyroid, liver, or chronic renal disease, or chronic hypertension.	Preeclampsia, Gestational hypertension SGA	mean
Vatten LJ, 2007	Norway, 1992-1994	nested case-control	Serum 4-12 weeks	Singleton pregnancies	Preeclampsia (preterm and term)	mean, OR
Wathen KA, 2006	Finland, 2001-2002	longitudinal case-control	Serum 2-15 weeks	Singleton pregnancies among Caucasian women Exclusions: women with history of hypertension, diabetes, chronic disease, or smoke > 5 cigarettes/day.	Preeclampsia IUGR	median, OR

All blood testing done using an ELISA testing kit developed by R&D Systems

SGA = small for gestational age; IUGR = intrauterine growth restriction