Prolonged and post-term pregnancies: guidelines for clinical practice from the French College of Gynecologists and Obstetricians (CNGOF).

The duration of pregnancy varies between 40(+0) and 41(+3) weeks. Conventionally, and essentially arbitrarily, a pregnancy is considered to be "prolonged" after 41(+0) weeks, but the infant is not considered "post-term" until 42(+0) weeks (Professional consensus). A term birth thus occurs during the period from 37(+0) to 41(+6) weeks.

Expired air carbon monoxide concentration in mothers and their spouses above 5 ppm is associated with decreased fetal growth.

Background: Smoking during pregnancy is associated with reduced birthweight; this relation can be reversed by smoking cessation. Some but not all previous studies have shown that smoking reduction (measured as cigarettes/day or urinary cotinine) may also improve birthweight. The relationship between maternal and spouses' expired air carbon monoxide (CO) concentrations (EACO) on fetal growth has not yet been evaluated.