Significance of highly phosphorylated insulin-like growth factor binding protein-1 and cervical length for prediction of preterm delivery in twin pregnancies

Table 1 Characteristics of the twin pregnancy populations recruited in the study

Characteristic
Maternal age (yr)	28.35 ± 4.84 (21-38)
Gravidity (times)	1.66 ± 0.35 (1-3)
Parity (times)	0.14 ± 0.03 (0-1)
Types of conception, n (%)
Spontaneous conception	250 (98.43)
Medical intervention	4 (1.57)
Gestational age (wk)	26.54 ± 3.24 (24-34)
Pregnancy complications, n (%)
Gestational diabetes	114 (44.88)
Gestational hypertension	36 (14.17)
Thyroid dysfunction	56 (22.05)
Other complications (e.g., placenta, amniotic fluid and baby positions in womb)	48 (18.90)

Table 2 Preterm delivery in patients with different central lengths and phosphorylated insulin-like growth factor binding protein-1 test results

Cervical length	Expression of phIGFBP-1	n	< 30 wk gestation	Between 30 and 34 wk gestation	Between 34 and 37 wk gestation	Preterm birth rate (%)
≤ 25 mm	Positive	63	20	13	12	45 (71.43)
	Negative	51	16	9	4	29 (56.86)
> 25 mm	Positive	60	0	1	3	13 (21.67)
	Negative	80	0	0	9	12 (15.00)

phIGFBP-1: Phosphorylated insulin-like growth factor binding protein-1.

Table 3 Predictive performance of phosphorylated insulin-like growth factor binding protein-1 expression combined with cervical length test for preterm delivery in twin pregnancies

Pregnancy outcomes	phIGFBP-1 expression combined with cervical length		Total
	+	-
+	156	8	164
-	7	83	90
Total	163	91	254

“+”: Preterm delivery; “-”: Non-preterm delivery; phIGFBP-1: Phosphorylated insulin-like growth factor binding protein-1.