The stalked barnacle Pollicipes pollicipes (Gmelin, 1789), is a strictly littoral and essentially intertidal pedunculate cirripede that lives by forming dense aggregates or clumps on exposed rocky shores and cliffs associated with a high degree of hydrodynamism (Barnes 1996).
Since some women are unsure of the date of their last menstruation (perhaps due to period irregularities), a baby is considered full term if its birth falls between 37 to 42 weeks of its estimated due date. 1  The unborn baby spends around 37 weeks in the uterus (womb), but the average length of pregnancy, or gestation, is calculated as 40 weeks.
Reviewed by Laura J. Martin, MD. May 23, 2011 -- Babies born between 39 and 41 weeks of pregnancy fare better than infants born during weeks 37 or 38, a study shows. A term birth is considered 37 to 41 weeks, but the new study suggests it is more of a continuum.The findings appear in Obstetrics & Gynecology.reviously it was thought that infant mortality risk was similar for babies born between 37 and 41 weeks. But the new study shows that this risk is increased when babies are born between 37 and 39 weeks of gestation, and that this risk decreases with each additional week of pregnancy.