Ultrasound-Indicated Cervical Cerclage Efficacy Between 16 and 28 Weeks of Gestation in Twin Pregnancy: Retrospective Cohort Study

Figures & data

Figure 1 The participants’ flow chart.

Table 1 Demographic and Gestational Characteristics

Characteristics	UIC Group (n=187)	Control Group (n=133)	P value
Female age (years)	32.2±3.4	32.1±3.4	0.758
BMI (kg/m^2)	26.1±3.2	25.1±2.7	0.081
Method of conception (n, %)			0.213
Natural conception	25 (13.37)	25 (18.80)
IVF/ICSI	162 (86.63)	108 (81.20)
Chorionicity (n, %)			0.109
DCDA	178 (95.19)	131 (98.50)
MCDA	9 (4.81)	2 (1.50)
Mode of delivery (n, %)			0.091
Natural birth	50 (26.74)	25 (18.80)
Forceps	2 (1.07)	1 (0.75)
Cesarean section	135 (72.19)	107 (80.45)
Maternal diseases (n, %)
Hypertensive disorder	12 (6.42)	10 (7.52)	0.823
Gestational diabetes mellitus	19 (10.16)	23 (17.29)	0.067
Others	8 (4.28)	9 (6.77)	0.449
Nulliparous	175 (93.58)	123 (92.48)	0.823
Previous first-trimester pregnancy losses
0	78 (41.71)	57 (42.86)	0.909
1	76 (40.43)	58 (42.34)	0.734
≧2	33 (17.55)	18 (13.14)	0.354
Cervical length (mm)	13.1±7.0	14.2±7.2	0.145

Abbreviations: BMI, body mass index; IVF, in vitro fertilization; ICSI, intracytoplasmic sperm injection; DCDA, dichorionic-diamniotic; MCDA, monochorionic-diamniotic.

Table 2 Delivery and Neonatal Outcomes of Twin Pregnancies with a Short Cervix

Variable	UIC Group (n=187)	Control Group (n=133)	OR (95% CI)	P value
PTB<34 week	95 (50.80)	72 (54.14)	0.88 (0.56–1.37)	0.572
PTB<37 week	152 (81.28)	112 (84.21)	0.81 (0.45–1.47)	0.552
PTB<32 week	69 (36.90)	55 (41.35)	0.82 (0.52–1.29)	0.485
PTB<28 week	23 (12.30)	26 (19.55)	0.58 (0.31–1.06)	0.084
PPROM (n, %)	41 (21.93)	43 (32.33)	1.70 (1.03–2.81)	0.040*
Intrauterine infection (n, %)	2 (1.07)	1 (0.75)	0.70 (0.06–7.80)	0.771
GA at delivery (week)	32.49±4.43	32.00±4.97		0.357
Perinatal mortality (n, %)	53 (14.17)	48 (18.05)	1.33 (0.87–2.04)	0.189
Birth weight (g)	1927 (1320, 2460)	2150 (1266, 2395)		0.913
LBW<2500 g	284 (75.94)	214 (80.45)	0.77 (0.52–1.13)	0.178
VLBW<1500 g	120 (32.09)	98 (36.84)	0.81 (0.58–1.13)	0.236
Admission to NICU (born alive only)	152/321(47.35)	120/218 (55.05)	1.36 (0.96–1.92)	0.095

Note: *P < 0.05.

Abbreviations: OR, odds ratio; CI, confidence interval; PPROM, premature rupture of membranes; PTB, preterm birth; GA, gestational age; LBW, low birth weight; VLBW, very low birth weight; NICU, neonatal intensive care unit.

Table 3 Logistic Regression Analysis for PTB Risk at <34 Weeks

Variables	Crude OR (95% CI)	P value	Adjusted OR (95% CI)	P value
Cerclage or not	0.83 (0.53–1.29)	0.398	0.20 (0.06–0.66)	0.008*
Diagnosis time for short cervix	0.21 (1.12–1.30)	0.000*	1.39 (1.18–1.64)	0.000*
Cervical length	1.11 (1.08–1.15)	0.000*	1.15 (1.07–1.24)	0.001*
Female age	1.06 (1.00–1.13)	0.055	1.09 (0.97–1.22)	0.160
Body mass index	0.99 (0.87–1.13)	0.854	1.12 (0.93–1.35)	0.229
Method of pregnancy	1.91 (0.94–3.88)	0.074	1.44 (0.49–4.23)	0.513
Maternal diseases	0.75 (0.45–1.28)	0.293	0.35 (0.11–1.15)	0.083
Nulliparous	2.07 (0.82–5.23)	1.222	0.40 (0.07–2.44)	0.318
Previous first-trimester pregnancy losses	0.77 (0.49–1.20)	0.242	1.61 (0.65–3.97)	0.305

Note: *P < 0.05.

Abbreviations: OR, odds ratio; CI, confidence interval.

Table 4 Subgroup Analysis Delivery Outcomes of Twin Pregnancies

	UIC Group	Control Group	OR (95% CI)	P value
Subgroup 1: According to cervical length
PTB<34 week
CL≦15 mm	62/102 (60.78)	54/69 (78.26)	0.43 (0.22–0.86)	0.020*
CL>15 mm	33/85 (38.82)	18/64 (28.13)	1.62 (0.81–3.26)	0.222
PTB<37 week
CL≦15 mm	87/102 (85.29)	65/69 (94.20)	0.36 (0.11–1.13)	0.084
CL>15 mm	65/85 (76.47)	47/64 (73.43)	1.18 (0.56–2.48)	0.705
PTB< 32 week
CL≦15 mm	46/102 (45.10)	44/69 (63.77)	0.47 (0.25–0.87)	0.019*
CL>15 mm	23/85 (27.06)	11/64 (17.19)	1.79 (0.80–4.00)	0.172
PTB< 28 week
CL≦15 mm	15/102 (14.71)	21/69 (30.43)	0.39 (0.19–0.84)	0.021*
CL>15 mm	8/85 (9.41)	5/64 (7.81)	1.23 (0.38–3.94)	0.732
GA at delivery (week)
CL≦15 mm	31.55±4.48	30.09±4.84		0.034*
CL>15 mm	33.63±4.12	34.14±4.17		0.452
Subgroup 2: According to GA at diagnosis of short cervix
PTB< 34 week
GA≦24 week	84/143 (61.54)	51/59 (84.75)	0.29 (0.13–0.63)	0.001*
GA>24 week	11/44 (20.45)	21/74 (32.43)	0.54 (0.22–1.29)	0.205
PTB< 37 week
GA≦24 week	119/143 (83.21)	57/59 (96.61)	0.17 (0.04–0.76)	0.010*
GA>24 week	33/44 (75)	55/74 (74.32)	1.04 (0.44–2.45)	0.935
PTB< 32 week
GA≦24 week	61/143 (46.15)	44/59 (74.58)	0.29 (0.15–0.57)	0.000*
GA>24 week	8/44 (18.18)	11/74 (13.51)	1.27 (0.47–3.46)	0.796
PTB< 28 week
GA≦24 week	22/143 (18.18)	24/59 (38.98)	0.35 (0.18–0.68)	0.003*
GA>24 week	1/44 (4.55)	2/74 (2.70)	0.84 (0.07–9.51)	0.886
GA at delivery (week)
GA≦24 week	31.75±4.57	28.20±4.99		0.000*
GA>24 week	34.73±3.08	34.91±2.43		0.722

Note: *P < 0.05.

Abbreviations: OR, odds ratio; CI, confidence interval; PTB, preterm birth; CL, cervical length; GA, gestational age.

Table 5 Subgroup Analysis Neonatal Outcomes of Twin Pregnancies

	UIC Group	Control Group	OR (95% CI)	P value
Subgroup 1: According to cervical length
Perinatal mortality (n, %)
CL≦15 mm	31/204 (15.20)	35/138 (25.36)	1.90 (1.10–3.26)	0.025*
CL>15 mm	22/170 (12.94)	13/128 (10.16)	0.76 (0.37–1.57)	0.586
Birth Weight (g)
CL≦15 mm	1735±746	1520±824		0.021*
CL>15 mm	1960±777	2098±761		0.126
Low birth weight (<2500g)
CL≦15 mm	165/204 (80.88)	128/138 (92.75)	0.33 (0.16–0.69)	0.003*
CL>15 mm	119/170 (70)	86/128 (67.19)	1.14 (0.70–1.87)	0.616
Very low birth weight (<1500 g)
CL≦15 mm	80/204 (39.22)	74/138 (53.62)	0.56 (0.36–0.86)	0.011*
CL>15 mm	40/170 (23.53)	24/128 (18.75)	1.33 (0.76–2.35)	0.393
Admission to NICU (born alive only)
CL≦15 mm	97/173 (56.07)	75/103 (72.82)	2.10 (1.24–3.56)	0.007*
CL>15 mm	55/148 (37.16)	45/115 (39.13)	1.09 (0.66–1.80)	0.798
Subgroup 2: According to GA at diagnosis of short cervix
Perinatal mortality (n, %)
GA≦24 week	49/286 (17.13)	46/118 (38.98)	2.01 (1.27–3.18)	0.004*
GA>24 week	4/88 (4.55)	2/148 (1.35)	0.29 (0.05–1.60)	0.132
Birth Weight (g)
GA≦24 week	1792 (1251, 2391)	1200 (450, 1930)		0.000*
GA>24 week	2405 (1800, 2723)	2325 (2181, 2555)		0.973
Low birth weight (<2500 g)
GA≦24 week	232/286 (81.12)	110/118 (93.22)	0.32 (0.15–0.70)	0.002*
GA>24 week	52/88 (59.09)	104/148 (70.27)	0.61 (0.35–1.06)	0.089
Very low birth weight (<1500 g)
GA≦24 week	106/286 (37.06)	84/118 (71.19)	0.24 (0.15–0.38)	0.000*
GA>24 week	14/88 (15.91)	14/148 (9.46)	1.81 (0.82–4.00)	0.150
Admission to NICU (born alive only)
GA≦24 week	122/237 (51.48)	52/72 (72.22)	2.45 (1.38–4.36)	0.002*
GA>24 week	30/84 (35.71)	68/146 (46.58)	1.57 (0.90–2.73)	0.128

Note: *P < 0.05.

Abbreviations: OR, odds ratio; CI, confidence interval; CL, cervical length; NICU, neonatal intensive care unit; GA, gestational age.

Figure 2 KM curves generated from CL subgroup analysis. Proportion KM curves in women with twin pregnancy and a short cervix with no delivery across gestation and treated with cervical cerclages (UIC group) compared with the expectant management (control group). CL-based subgroup analysis; (A) showed a CL of ≦15 mm, and (B) showed a CL of >15 mm. Group comparison using the Log rank test showed a significant difference (HR = 1.55; CI = 95% [1.08–2.24]; and p = 0.018) in (A), with no difference between the two groups in (B). Red curve cases with a short cervix treated with ultrasound-indicated cerclage; blue curve cases with expectant management.

Figure 3 KM curves generated from subgroup analysis of first short cervix diagnosis GA. Proportion KM curves in twin pregnancies in women with twin pregnancy and a short cervix with no delivery across gestation, treated with cervical cerclages (UIC group) compared with women with expectant management (control group). Subgroup analysis according to the first short cervix diagnosis GA; (A) Showed a GA of ≦24 weeks, and (B) showed a GA of >24 weeks. Group comparison using the Log rank test showed a significant difference (HR = 2.29; CI = 95% [1.61–3.26]); and p = 0.000) in (A) and no difference between in (B). Red curve cases with cerclage, blue curve cases with management treatment.