Uterocervical Angle and Cervical Length as a Tool to Predict Preterm Birth in Threatened Preterm Labor

Figures & data

Figure 1 UCA by TVS.

Table 1 Patient Characteristics

Variables	Outcomes (N)			p-value
	Term (N=117)	Preterm (N=43)	Total (N=160)
Age (mean, SD)	28.8 (5.7)	30.1 (6.9)	29.1 (6.1)	0.219
Hospital				0.528
- SNH (%)	90 (76.9)	31 (72.1)	121 (75.6)
- UDH (%)	27 (23.1)	12 (27.9)	39 (24.4)
UCA (median, IQR)	113.4 (105.9,120.9)	113.3 (97.8,124)	113.4 (104.9,122)	0.929
GA at TVU (median, IQR)	35^+1 (33^+2,36^+3)	34^+0 (32^+0,34^+5)	35^+0 (33^+0,36^+3)
CL (median, IQR)	3.4 (2.6,4)	3 (2.5,3.5)	3.2 (2.5,3.9)	0.032*
BMI at conception (median, IQR)	20.3 (18.4,22.9)	21 (18.9,23.6)	20.4 (18.4,23)	0.409
BMI at delivery (median, IQR)	24.5 (22.8,27.7)	24.7 (22.5,27.5)	24.6 (22.8,27.7)	0.873
Parity				0.491
- Nulliparous (%)	67 (57.3)	22 (51.2)	89 (55.6)
Prior spontaneous preterm	8 (6.8)	4 (9.3)	12 (7.5)	0.735
Prior dilatation and curettage (D&C)	9 (7.7)	2 (4.7)	11 (6.9)	0.729
Prior cervical conization	0 (0)	1 (2.3)	1 (0.6)	0.269
Prior LEEP	0 (0)	0 (0)	0 (0)
Abnormal Pap	2 (1.7)	0 (0)	2 (1.2)	> 0.999
Smoking	1 (0.9)	1 (2.3)	2 (1.2)	0.467
Gestational diabetes mellitus	16 (13.7)	6 (14)	22 (13.8)	0.964
Hypertension	5 (4.3)	2 (4.7)	7 (4.4)	> 0.999
Route of delivery				0.748
- Normal labor (%)	82 (70.1)	29 (67.4)	111 (69.4)
- Cesarean section (%)	35 (29.9)	14 (32.6)	49 (30.6)
Cesarean section				0.515
- Primary (%)	24 (66.7)	7 (50)	31 (62)
- Repeated (%)	11 (30.6)	7 (50)	18 (36)

Note: *Statistically significant at an alpha level of 0.05.

Table 2 Odds Ratios and Associated 95% Confidence Intervals for Independent Predictors of Preterm Birth in Logistic Regression Model (N=160)

Variables	Odds Ratio	95% CI	p-value
CL<3.4 cm	1.92	0.58–6.42	0.29
UCA≥110.97 degrees	1.21	0.34–4.28	0.77
UCA≥110.97 degrees and CL<3.4 cm	1.22	0.26–5.80	0.80

Figure 2 The receiver operating characteristic (ROC) curve between UCA and CL and preterm birth.

Table 3 Diagnostic Performance of Uterocervical Angle and Cervical Length for Prediction of Preterm Delivery

Parameters	Sensitivity	Specificity	PPV	NPV	PLR	NLR	ROC Area
UCA ≥110.97 degrees	65.1% (49.1–79.0)	43.6% (34.4–53.1)	29.8% (20.8–40.1)	77.3% (65.3–86.7)	1.15	0.8	0.544
CL <3.4 cm	72.1% (72.1–56.3)	46.2% (36.9–55.6)	33% (23.6–43.4)	81.8% (70.4–90.2)	1.34	0.61	0.591
UCA≥110.97 degrees and CL<3.4 cm	48.8% (33.3–64.5)	68.4% (59.1–76.7)	36.2% (24.0–49.9)	78.4% (69.2–86)	1.54	0.75	0.586