REN and diabetes mellitus: The intake of pancreatic hormones (i.e., glucagon) and drugs used in diabetes, as well as the exemption for diabetes mellitus, identify people affected by diabetes, a condition that has been shown to be associated with PTB [19,20], while agents acting on the renin–angiotensin system, beta-blocking and calcium channel blockers are drugs commonly used for the treatment of hypertension [21], another strong predictor of preterm delivery [22].