Table 2.

Characteristics of women and Doppler assessments in included studies

Study population	N (studies)	%
Maternal risk
Low-risk women only	36	85.7
Unselected women	6	14.3
Doppler assessments
Doppler ultrasound of umbilical artery only reported	15	35.7
Doppler ultrasound of umbilical artery plus other  Doppler investigations reporteda	27	64.2
Type of Doppler
Colour Doppler	12	28.6
Continuous-wave Doppler	6	14.3
Pulsed-wave Doppler	6	14.3
Pulsed-wave Doppler; colour Doppler	9	21.4
Pulsed-wave and continuous-wave Doppler	1	2.1
Doppler (not otherwise specified)	8	19.0

^aFetal cerebral circulation, fetal aorta, fetal renal arteries, umbilical vein, ventricular outlets, femoral vessels, uterine/placental vessels