Table 1.

Baseline characteristics of pooled women

Characteristic	Vaginal progesterone (n = 159)	Placebo/no treatment (n = 144)
Maternal age (years)	27 (25–30)	28 (25–31)
Body mass index (kg/m2)	22.4 (21.2–25.7)*	22.9 (21.0–25.4)†
Smoker	3 (1.9)	3 (2.1)
Previous spontaneous PTB	28 (17.6)	28 (19.4)
Monochorionic pregnancy	8 (5.0)	6 (4.2)
GA at randomization (weeks)	21.7 (20.6–23.1)	22.1 (21.1–23.3)
CL at randomization (mm)	22 (20–23)	22 (20–23)
CL ≤ 20 mm at randomization	49 (30.8)	47 (32.6)

Data are given as median (interquartile range) or n (%).

^* n = 41.

^† n = 36.

CL, cervical length; GA, gestational age; PTB, preterm birth.