Distribution of the studied quantitative indicators. The vertical axes expresses the number of the patients distributed of the following indicators at the horizontal axes: A) age (years) (p<0.001); B) birth in a completed gestational week (p<0.001); C) sequence of pregnancy (p<0.001); D) previous miscarriages (p<0.001); E) previous interruptions (p<0.001); F) inter-delivery period (p<0.001); G) weight of the patient (kg) (p<0.001); H) height of the patient (m) (p<0.001); I) Body mass index (kg/m2) (p<0.001).