Predictive performance of cervical elastography for preterm birth: A head-to-head network meta-analysis

Table 1 Characteristics of the included studies (n = 15)

Ref.	Country	Study design	Pregnancy status	Gestational weeks	Mean age (in years)	Sample size (PTB/TD)	Detection method	Ultrasonic diagnostic device
Zhang et al[14], 2021	China	Retrospective	Singleton pregnancy	16~28	22~41 (30.01 ± 4.03)	171 (24/147)	CL, IOS, IOS/EOS ratio, HR	Samsung Medison WS80A
Xiong et al[15], 2021	China	Retrospective	Singleton pregnancy	20~24	PTB: 26 (23.75, 27.00); TD: 26 (25.00, 27.00)	85 (40/45)	CL, IOS, ECI, EOS	Samsung Medison WS80A
Wang et al[16], 2022	China	Retrospective	Singleton pregnancy	14~28	20~36 (29.96 ± 3.01)	200 (31/169)	CL, ECI, IOS, IOS/EOS ratio, HR	Samsung Medison WS80A
Cha et al[17], 2022	Korea	Prospective	Singleton pregnancy	14~24	PTB: 33.8 ± 3.8; TD: 34.2 ± 3.8	66 (8/58)	CL, ECI, EOS, IOS, HR	Samsung Medison WS80A
Nazzaro et al[18], 2022	Italy	Retrospective	Singleton pregnancy	23~33	PTB: 28.9 ± 6.1; TD: 28.4 ± 6.1	95 (42/53)	CL, HR	Samsung Medison WS80A
Li et al[19], 2023	China	Retrospective	Singleton Pregnancy	14~27 and 28~36	PTB: 34 (29, 37); TD: 31 (28, 32)	149 (31/118)	HR	Samsung HERA W10/W9
Li et al[20], 2023	China	Retrospective	Singleton pregnancy	16~28 and 22~24	PTB: 24~37 (29.7 ± 3.6); TD: 24~37 (29.6 ± 3.6)	82 (14/68)	ACA, ECI, IOS/EOS ratio, HR	Samsung (NR)
Wu et al[21], 2024	China	Retrospective	Singleton and multiple pregnancy	18~27	23~40 (30.22 ± 4.03)	225 (105/120)	ECI, EOS, IOS	Samsung HERA W10
Liu et al[22], 2024	China	Prospective	Multiple pregnancy	18~24	21~40 (30.9 ± 3.8)	97 (35/62)	ACA, ECI, IOS, EOS, IOS/EOS ratio, HR	Samsung HERA W9
He et al[23], 2024	China	Prospective	Singleton pregnancy	18~24	PTB: 30.6 ± 3.2; TD: 30.2 ± 3.3	228 (26/202)	CL, EOS, IOS	Samsung Medison WS80A
Nazzaro et al[24], 2024	Italy	Retrospective	Multiple pregnancy	23~33	PTB: 27.9 ± 5.5; TD: 29.3 ± 6.2	63 (44/19)	CL, HR	Samsung Medison WS80A
Yu et al[25], 2025	China	Prospective	Multiple pregnancy	20~24	18~40 (32.50 ± 3.27)	130 (40/90)	CL, IOS, HR	Samsung HERA XW9
He et al[26], 2025	China	Retrospective	Singleton Pregnancy	16~28	22~40 (31.12 ± 4.06)	88 (21/67)	ACA, ECI, HR	Samsung (NR)
Ma et al[27], 2025	China	Retrospective	Singleton pregnancy	11~18	PTB: 29.10 ± 2.39; TD: 29.12 ± 2.36	136 (25/111)	CL, ACA, ECI, EOS, IOS, IOS/EOS ratio, HR	Samsung (NR)
Kwon et al[28], 2025	Korea	Prospective	Singleton and multiple pregnancy	24~34	PTB:34 (21, 40); TD: 33 (26, 42)	150 (84/66)	CL, ECI, IOS/EOS ratio	Samsung Medison WS80A

PTB: Preterm birth; TD: Term delivery; CL: Cervical length; ACA: Anterior cervical angle; ECI: Elasticity contrast index; IOS: Internal os strain; EOS: External os strain; HR: Hardness ratio.

Table 2 Combined area under the curve, sensitivity, specificity, and diagnostic odds ratio for E-cervix parameters and conventional measurement parameters

Parameters	AUC (95%CrI)	Sensitivity (95%CrI)	Specificity (95%CrI)	DOR (95%CrI)	LR+ (95%CrI)	LR- (95%CrI)	S	RR_Se vs CL	RR_Sp vs CL
CL	0.70 (0.60-0.77)	0.63 (0.54-0.71)	0.67 (0.57-0.76)	3.58 (1.91-6.25)	1.89 (1.24-2.90)	0.56 (0.39-0.82)	0.28 (0.08-1.00)	1.00 (1.00-1.00)	1.00 (1.00-1.00)
ACA	0.86 (0.71-0.93)	0.78 (0.65-0.89)	0.75 (0.58-0.87)	13.65 (3.88-35.20)	3.15 (1.55-7.04)	0.29 (0.13-0.61)	5.70 (0.33-15.00)	1.25 (1.01-1.53)	1.13 (0.86-1.40)
IOS	0.76 (0.65-0.83)	0.56 (0.45-0.67)	0.80 (0.70-0.87)	5.47 (2.59-10.06)	2.75 (1.50-5.13)	0.55 (0.38-0.78)	0.73 (0.14-3.00)	0.90 (0.71-1.10)	1.20 (1.01-1.44)
EOS	0.72 (0.68-0.76)	0.57 (0.51-0.64)	0.78 (0.75-0.81)	4.00 (2.81-5.69)	2.27 (1.65-3.12)	0.61 (0.50-0.75)	0.58 (0.08-2.33)	1.07 (0.86-1.29)	0.98 (0.75-1.24)
IOS/EOS ratio	0.72 (0.58-0.80)	0.68 (0.57-0.78)	0.63 (0.49-0.75)	4.05 (1.64-8.14)	1.84 (1.10-3.17)	0.50 (0.30-0.89)	0.46 (0.08-2.33)	1.09 (0.89-1.31)	0.95 (0.72-1.19)
ECI	0.73 (0.63-0.80)	0.67 (0.57-0.76)	0.67 (0.56-0.77)	4.52 (2.24-8.21)	2.04 (1.30-3.29)	0.49 (0.31-0.77)	0.60 (0.09-2.33)	1.08 (0.89-1.29)	1.01 (0.81-1.23)
HR	0.80 (0.72-0.85)	0.76 (0.68-0.82)	0.70 (0.60-0.78)	7.71 (4.06-13.06)	2.51 (1.69-3.75)	0.35 (0.23-0.54)	2.18 (0.20-9.00)	1.21 (1.04-1.41)	1.05 (0.87-1.28)
Combined	0.91 (0.83-0.95)	0.83 (0.74-0.89)	0.83 (0.73-0.90)	26.23 (10.47-54.64)	4.76 (2.70-8.74)	0.21 (0.12-0.36)	12.90 (3.67-15.00)	1.32 (1.13-1.55)	1.25 (1.04-1.48)

Heterogeneity was quantified using Cochran’s Q test and the I² statistic; a random-effects model was employed if I² > 50% or P < 0.10 for Cochran’s Q test, indicating significant heterogeneity; otherwise, a fixed-effects model was used. AUC: Area under the curve; CrI: Credible interval; DOR: Diagnostic odds ratios; LR: Likelihood ratios; S: Advantage index, a ranking metric for diagnostic performance; higher values indicate superior overall accuracy; RR_Se/RR_Sp vs CL: Relative ratio compared to cervical length (reference); CL: Cervical length; ACA: Anterior cervical angle; IOS: Internal os strain; EOS: External os strain; ECI: Elasticity contrast index; HR: Hardness ratio.

Table 3 Summary of heterogeneity analysis between E-cervix parameters and conventional measurement parameters

Parameters	Studies (n)	Pooled DOR (95%CI)	Cochran Q	P value (Q test)	I2 (%)	Spearman r	P value (Spearman)
CL	10	3.68 (1.88-7.22)	37.66	0.00	0.76	0.26	0.47
ACA	4	18.02 (7.92-40.98)	5.10	0.16	0.41	-0.80	0.20
ECI	9	4.92 (2.62-9.23)	23.75	0.00	0.71	-0.23	0.59
IOS	8	5.30 (3.88-7.25)	5.83	0.56	0.00	0.68	0.06
EOS	6	4.00 (2.81-5.69)	3.54	0.62	0.00	0.60	0.21
IOS/EOS	6	3.91 (1.45-10.57	32.90	0.00	0.85	-0.14	0.79
HR	11	10.92 (6.66-17.89)	20.32	0.03	0.51	0.45	0.16
Combined	7	35.27 (9.75-127.55)	40.02	0.00	0.85	-0.25	0.59

DOR: Diagnostic odds ratios; CI: Confidence interval; CL: Cervical length; ACA: Anterior cervical angle; IOS: Internal os strain; EOS: External os strain; ECI: Elasticity contrast index; HR: Hardness ratio.