Uterine artery Doppler at 11-14 weeks of gestation in the prediction of preeclampsia: An observational study

Table 1 Baseline characteristics of patients, mean ± SD/n (%)

Baseline characteristic	Pre-eclampsia group (n = 42)	Normal group (n = 300)	P value
Age (years)	31.0 ± 5	30.0 ± 5	0.23
Range	28-38	20-40
BMI (kg/m2)	24.29 ± 1.59	23.09 ± 1.87	0.15
GA at enrollment (weeks)	11.43 ± 0.65	11.66 ± 0.67	0.08
Parity
Nulliparous	18 (42.9)	180 (60.0)	0.0751
Primiparous	16 (38.1)	70 (23.3)
Multiparous	8 (19.0)	50 (16.7)
MAP (mmHg)	94.1 ± 14.3	87.9 ± 6.5	0.008a
Range	78-125	77-118

^aP < 0.05.

BMI: Body mass index; GA: Gestational age; MAP: Mean arterial pressure.

Table 2 Distribution of study participants according to gravida and parity status, n (%)

Parameters		Groups		P value
		Pre-eclampsia (n = 42)	Normal (n = 300)
Gravida	1	10 (23.8)	126 (42.0)	0.026
	2	10 (23.8)	94 (31.3)
	3	22 (52.4)	80 (26.7)
Parity	0	18 (42.9)	180 (60.0)	0.0748
	1	16 (38.1)	70 (23.3)
	2	8 (19.0)	50 (16.7)

Table 3 Timing and severity of preeclampsia in relation to uterine artery Doppler findings (n = 42), mean ± SD/n (%)

Parameter	Early-onset severe PE (n = 11)	Early-onset mild PE (n = 7)	Late-onset severe PE (n = 13)	Late-onset mild PE (n = 11)
Total PE cases (%)	26.2	16.7	31.0	26.2
Uterine artery PI	2.03 ± 0.01	1.97 ± 0.01	1.94 ± 0.02	1.91 ± 0.04
Bilateral notching	9 (81.8)	5 (71.4)	8 (61.5)	4 (36.4)
GA at diagnosis (weeks)	29.3 ± 1.4	30.9 ± 1.0	35.8 ± 0.9	36.4 ± 1.1
P value	< 0.001

PE: Pre-eclampsia; PI: Pulsatility index; GA: Gestational age.

Table 4 Pregnancy outcome of the study participants, mean ± SD/n (%)

		Pre-eclampsia group (n = 42)	Normal group (n = 300)	P value
Gestational age at birth (weeks)		34.4 ± 2.0	37.9 ± 1.6	< 0.001a
Mode of delivery	Vaginal	14 (33.3)	198 (66)	< 0.001a
	LSCS	28 (66.7)	102 (34)
Fetal complications	LBW	26 (61.9)	28 (9.3)	< 0.001a
	NICU admission	32 (76.1)	27(9)	< 0.001a
	Meconium-stained liquor	1 (2.3)	4 (1.3)	0.611

^aP < 0.001.

LSCS: Lower segment cesarean section; LBW: Low birth weight; NICU: Neonatal intensive care unit.

Table 5 Uterine artery notching among the study participants, n (%)

Uterine artery notching	Groups		P value
	Pre-eclampsia (n = 42)	Normal (n = 300)
Present	37 (88)	48 (16)	< 0.001a
Unilateral notching	11 (29.7)	32 (66.6)
Bilateral notching	26 (70.3)	16 (33.4)
Absent	5 (12)	252 (84)

^aP < 0.001.

Table 6 Comparison of uterine artery Doppler indices

Parameter	Preeclampsia (n = 42)	Normal (n = 300)	P value
Right UA-PI	1.955 ± 0.35	1.481 ± 0.53	< 0.001a
Left UA-PI	1.936 ± 0.39	1.467 ± 0.58
Mean PI	1.9455 ± 0.36	1.4740 ± 0.52
Right UA-RI	0.750 ± 0.12	0.551 ± 0.21
Left UA-RI	0.746 ± 0.14	0.516 ± 0.23
Mean RI	0.748 ± 0.13	0.5335 ± 0.22

^aP < 0.001.

UA: Umbilical artery; PI: Pulsatility index; RI: Resistive index.

Table 7 Sensitivity analysis-model excluding resistive index

Predictor	Adjusted OR	95%CI	P value
PI (per 0.1 unit)	1.21	1.13-1.29	< 0.001
BMI (per 1 kg/m2)	1.42	1.15-1.74	0.001
MAP (per 1 mmHg)	1.06	1.01-1.10	0.009

PI: Pulsatility index; BMI: Body mass index; MAP: Mean arterial pressure; OR: Odds ratio; CI: Confidence internal.

Table 8 Multivariable logistic regression for prediction of preeclampsia

Predictor	Adjusted OR	95%CI	P value
PI (per 0.1 unit)	1.07	0.96-1.20	0.001
RI (per 0.1 unit)	1.47	1.07-2.01
BMI (per 1 kg/m2)	1.43	1.16-1.76
MAP (per 1 mmHg)	1.05	1.01-1.10	0.014

Model includes pulsatility index (PI), resistive index (RI), body mass index, and mean arterial pressure; RI and PI rescaled per 0.1-unit increase. Odds ratio for PI and RI rescaled to 0.1 unit increases to improve interpretability. Model adjusted for body mass index and mean arterial pressure. PI: Pulsatility index; RI: Resistive index; BMI: Body mass index; MAP: Mean arterial pressure; OR: Odds ratio; CI: Confidence internal.

Table 9 Receiver operating characteristic analysis for pulsatility index as predictor of pre-eclampsia

Parameter	Value
AUC	0.896
P value	< 0.001
Cut-off	1.622
95%CI (sensitivity)	0.66-0.82
95%CI (specificity)	0.78-0.91
Sensitivity	75.0%
Specificity	86.0%
PPV	84.27%
NPV	77.48%
Diagnostic accuracy	80.50%

AUC: Area under the curve; CI: Confidence internal; PPV: Positive predictive value; NPV: Negative predictive value.

Table 10 Receiver operating characteristic analysis resistive index as predictor of pre-eclampsia

Parameter	Value
AUC	0.920
P value	< 0.001
Cut-off	0.66
95%CI (sensitivity)	0.54-0.73
95%CI (specificity)	0.86-0.97
Sensitivity	64.0%
Specificity	93.0%
PPV	90.14%
NPV	72.09%
Diagnostic accuracy	78.50%

AUC: Area under the curve; CI: Confidence internal; PPV: Positive predictive value; NPV: Negative predictive value.