Independent risk factors for twin pregnancy adverse fetal outcomes before 28 gestational week by first trimester ultrasound screening

Table 1 Pregnancy outcomes in the abnormal group (n = 29)

Pregnancy outcomes	n
One of the twins died in utero	9
Selective fetal reduction, for one fetus with omphalocele (Figure 1)	1
Both of the twins died in utero	1
Spontaneous abortion	14
Induced abortion for fetal anomaly	4

Table 2 Abnormal ultrasound findings during first trimester screening in the two groups

Abnormal group	Control group
Seven cases of one intrauterine fetal death	One case with one fetus showing NT ≥ 3.0 mm
One case of twin reversed arterial perfusion sequence	One case with both fetuses showing NT ≥ 3.0 mm
One case of one fetus with omphalocele
One case of one fetus with gastroschisis
One case of one fetus with hydrops fetalis
One case of one fetus with NT ≥ 3.0 mm
One case of one intrauterine fetal death and the other with NT ≥ 3.0 mm

NT: Nuchal translucency.

Table 3 Comparison of first trimester screening results and personal history between the abnormal group and the control group

Characteristics	Abnormal group (n = 29)	Control group (n = 97)	P value
Maternal age (years)	32.39 ± 3.65	31.62 ± 4.07	0.333
Maternal age (≥ 35 years)	6 (20.69)	28 (28.87)	0.384
Assisted conception	11 (37.93)	46 (47.42)	0.368
Systolic blood pressure	113.17 ± 9.74	111.24 ± 9.77	0.351
Diastolic blood pressure	73.00 ± 7.40	71.82 ± 8.01	0.482
Mean arterial pressure	86.39 ± 7.59	84.96 ± 7.74	0.383
High blood pressure	3 (10.34)	8 (8.25)	0.714
BMI (kg/m2)	22.42 ± 3.40	22.21 ± 3.13	0.753
BMI ≥ 24 kg/m2	6 (20.69)	30 (30.93)	0.284
BMI ≥ 30 kg/m2	1 (3.44)	2 (2.06)	0.547
History of hysteroscopy	8 (27.59)	29 (29.90)	0.811
History of anti-phospholipid syndrome	2 (6.90)	2 (2.06)	0.333
Family history of high blood pressure	6 (20.69)	30 (30.93)	0.284
Nulliparous	16 (55.17)	47 (48.45)	0.525
Chorionicity			0.009
Dichorionic diamniotic	16 (55.17)	77 (79.38)
Monochorionic diamniotic	13 (44.83)	20 (20.62)
Mean PI of bilateral uterine arteries	1.57 ± 0.55	1.28 ± 0.42	0.003
Mean RI of bilateral uterine arteries	0.71 ± 0.11	0.65 ± 0.11	0.008
Early diastolic notch in bilateral uterine arteries	10 (34.48)	15 (15.46)	0.024
Early diastolic notch in at least one uterine artery	15 (51.72)	39 (40.21)	0.271
Abnormal ultrasound findings during first trimester screening	13 (44.83)	2 (2.06)	< 0.001
Crown-rump length discordance ≥ 10%	3 (3/20, 15)	6 (6.19)	0.181

Data are given as mean ± standard error or n (%). BMI: Body mass index; PI: Pulsatility index; RI: Resistance index.

Table 4 Results of bivariate logistic regression analysis suggestive of adverse pregnancy outcome

Characteristics	Odd ratios	95% confidence interval	P value
Mean PI of bilateral uterine arteries	3.524	1.015-12.236	0.047
Abnormal ultrasound findings during first trimester screening	56.146	10.086-312.547	< 0.001
Chorionicity	0.276	0.088-0.862	0.027

PI: Pulsatility index.