Medical records
The medical records relating to the infant’s and mother’s health were examined soon after birth. Information relevant to the infant’s health included: date of birth, gestation at birth, birth weight, sex, race, congenital abnormalities, Apgar score and resuscitation at birth. Information relevant to the mother’s health included; gestation at first visit, booking blood pressure, hospitalization during pregnancy, onset of labour, postnatal hospital stay in days and some laboratory test results.