The letters in this expression indicate obstetric history as follows:
Often, 4 numbers separated by hyphens are recorded, eg:
TPAL: 3-1-1-4 or 3-1-1-4
which would indicate 3 term deliveries, 1 premature delivery, 1 abortion, and 4 living children. However, the text of a manuscript should define the numerical expressions and not give the numbers alone.