The term ‘adverse pregnancy outcomes’ usually refers to low weight at birth, i.e. to newborns that weigh below 2500 grams. Among these low-weight infants, the worst-off group includes those weighing below 1500 grams, who were also delivered pre-term (i.e. before the 37th week of gestation). All these babies face higher neonatal and infant mortality, as well as worse health during childhood and adulthood. Conditions such as growth retardation, neurological problems, hypertension, stroke, coronary heart disease, etc. have been linked to low weight at birth. Another adverse outcome is ‘heavy birth weight’ (i.e. weighing above 4500 grams), as it is linked to both complications during delivery and higher morbidity (for instance, diabetes and heart disease).