Table 1.
Demographic and clinical characteristics of women with singleton and twin pregnancies
| Characteristics, n (%) | Twin pregnancy (n = 1346) | Singleton pregnancy (n = 15 562) | Statistic (χ2) | P-value |
|---|---|---|---|---|
| Age in years |
30.93 (28.61,33.44) |
30.58 (27.60,33.92) |
−2.739 |
0.006* |
| PBMI, mdn (Q1, Q3) |
21.50 (20.03,23.53) |
21.23 (19.10,23.73) |
−4.540 |
<0.001* |
| ART |
298 (22.14) |
298 (1.92) |
1490.101 |
<0.001* |
| Nulliparity |
1162 (86.33) |
9907 (63.66) |
281.577 |
<0.001* |
| Primigravida |
702 (52.16) |
5344 (34.34) |
171.148 |
<0.001* |
| Age of first menstruation |
12.00 (11.00,13.00) |
12.00 (11.00,13.00) |
−1.495 |
0.117 |
| History of caesarean section |
3 (0.22) |
580 (3.73) |
45.693 |
<0.001* |
| History of smoking |
26 (1.94) |
430 (2.78) |
3.317 |
0.069 |
| History of alcoholism |
181 (13.59) |
2463 (16.05) |
5.570 |
0.018* |
| Uterine myoma |
61 (4.53) |
687 (4.42) |
0.040 |
0.841 |
| Anaemia |
203 (15.08) |
1421 (9.13) |
50.523 |
<0.001* |
| Hypothyroidism |
147 (10.92) |
2275 (14.62) |
13.802 |
<0.001* |
| GDM |
493 (36.63) |
5636 (36.22) |
0.090 |
0.764 |
| PE |
253 (18.80) |
627 (4.03) |
547.581 |
<0.001* |
| FGR |
103 (7.65) |
215 (1.38) |
263.977 |
<0.001* |
| ICP |
228 (16.94) |
611 (3.93) |
444.833 |
<0.001* |
| Racquet placenta |
61 (4.53) |
479 (3.08) |
8.470 |
0.004* |
| Velaria placenta |
41 (3.05) |
110 (0.71) |
76.589 |
<0.001* |
| Placenta accreta |
175 (13.00) |
1202 (7.72) |
46.125 |
<0.001* |
| Placenta accreta with bleeding |
43 (3.20) |
184 (1.18) |
37.873 |
<0.001* |
| Placenta previa |
43 (3.20) |
396 (2.55) |
2.070 |
0.150 |
| Placenta previa with bleeding |
21 (1.56) |
123 (0.79) |
8.694 |
0.003* |
| Central placenta previa |
21 (1.56) |
178 (1.14) |
1.847 |
0.174 |
| Marginal placenta previa |
18 (1.34) |
170 (1.09) |
0.676 |
0.411 |
| Low-lying placenta |
8 (0.59) |
137 (0.88) |
1.192 |
0.275 |
| Placenta previa with placenta accreta | 18 (1.34) | 144 (0.93) | 2.216 | 0.137 |
ART – assisted reproductive technology, GDM – gestational diabetes mellitus, FGR – foetal growth restriction, ICP – intrahepatic cholestasis of pregnancy, mdn – median, PBMI – pre-pregnancy body mass index, PE – preeclampsia, Q1 – 1st quartile, Q3 – 3st quartile
*P < 0.05.