When less
blood flows to the uterus, it can cause problems for a baby, such as
poor growth, too little amniotic fluid, and
placental abruption (when the placenta separates from the uterine wall before delivery).
Longitudinal studies are needed to test the specific mechanisms that may explain these associations, such as prenatal health behaviours (smoking, alcohol, drug use,
poor weight gain), constricted uterine
placental blood flow, fetal neurobehavioural profile (e.g., heart rate), and obstetrical outcomes (e.g., low birth weight).