Figure 3.

Preterm birth rate
Spontaneous preterm birth rate before 37, 34, 32, and 28 weeks of pregnancy for women in the progesterone treatment group (red) and the no treatment group (blue).

Preterm birth rate
Spontaneous preterm birth rate before 37, 34, 32, and 28 weeks of pregnancy for women in the progesterone treatment group (red) and the no treatment group (blue).