Table 1 Baseline characteristics of women with multiple pregnancies

Age – years ^a

30.1 ± 5.9

Age group—n (%)

 • < 20 years

21 (4.9)

 • 20–34 years

306 (71.7)

 • ≥ 35 years

100 (23.4)

Mean pre-pregnancy BMI (kg/m²)

21.65 (3.9)

BMI category – n (%)

 • < 18.5 kg/m²

87 (20.3)

 • 18.5 – 24.9 kg/m²

264 (61.8)

 • 25 – 29.9 kg/m²

62 (14.6)

 • ≥ 30 kg/m²

14 (3.3)

Mean weight gain during pregnancy – kg ^a

15.2 ± 5.9

Nulliparous – n (%)

197 (46.1)

History of preterm birth – n (%)

11 (2.6)

In vitro fertilization method—n (%)

71 (16.6)

Underlying medical conditions

 • Anemia—n (%)

64 (14.9)

 • Chronic hypertension—n (%)

6 (1.4)

 • Overt diabetes mellitus—n (%)

2 (0.5)

 • Hypothyroidism—n (%)

7 (1.6)

 • Hyperthyroidism—n (%)

7 (1.6)

 • Connective tissue diseases—n (%)^b

1 (0.2)

Twins—n (%)

413 (96.7)

 • Dichorionic diamniotic– n (%)

172 (41.65)

 • Monochorionic diamniotic– n (%)

219 (53.03)

 • Monochorionic monoamniotic– n (%)

22 (5.15)

Triplets—n (%)

13 (3.04)

Quadruplets—n (%)

1 (0.23)