Great question! Per Department of State policy (16 FAM 317.1(b)), OB Medevac per diem includes up to 45 days before your estimated due date and 45 days after delivery. If the baby arrives early, it resets your 45-day, post-delivery date clock based upon his/her birthday. Thus, if the baby arrived on 5 Apr instead of the expected/authorized 10 Apr, that would mean five less days you would receive per diem out of the total 90 allocated days, meaning only 85 days of per diem in this case. The post-delivery 45-day period adjusts forward from the actual delivery date, but the pre-delivery portion does not retroactively gain extra reimbursable days because the per diem structure is fixed. Therefore, you lose per diem when the baby is early. Because we establish our original agreements upon the standard 90 days, we would simply revise the agreement to reflect the new dates and per diem calculation.