Birthweight and Gestational age
Birthweight (measured in grams) was extracted from the MBRN and was
treated as a continuous scale producing a mean value of 3,608 (SD
544.8). Gestational age (measured in days) was also treated as a
continuous variable and the mean score was 39.5 (SD 1.72). All maternity
units in Norway must notify the MBRN of all births and pregnancies
terminating after week 12. The MBRN includes information on pre- and
post-pregnancy variables including medication, birth complication, and
maternal complications.