Table 3

Day-by-day survival rate to discharge recalculated at fixed intervals on the surviving cohort and stratified by gestation among male and female infants 22–31 weeks' gestation born between 1997 and 2006 and admitted to a neonatal intensive care unit

			Day-by-day survival (%)
Gestation (weeks)	Total admitted	Total survived	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6	Day 7	Overall
Male infants
22	6	0	16.7	0.0	–	–	–	–	–	0
23	60	15	63.3	92.1	88.6	93.5	96.6	89.3	96.0	25
24	211	103	83.4	93.8	93.3	96.1	96.6	97.9	99.3	48.8
25	270	169	85.9	96.1	93.7	99.5	98.6	98.5	99.0	62.6
26	388	290	93.3	96.1	95.7	99.7	99.7	99.4	98.5	74.7
27	421	380	97.6	98.8	99.5	99.0	99.8	99.5	99.5	90.3
28	562	524	97.5	99.3	99.8	99.6	99.6	99.8	99.6	93.2
29	643	612	98.4	99.5	99.7	99.5	99.4	99.8	99.8	95.2
30	881	859	99.4	99.7	99.8	99.9	99.8	99.8	99.9	97.5
31	1081	1065	99.3	99.9	99.8	99.9	99.9	99.9	100.0	98.5
Overall (22–31)	4523	4017	96.2	98.8	98.8	99.5	99.6	99.7	99.7	88.8
Female infants
22	2	0	50.0	0.0	–	–	–	–	–	0
23	60	21	72.6	90.7	91.1	98.2	94.9	98.2	98.3	35.0
24	172	89	85.5	94.6	97.0	96.4	99.4	97.7	97.6	51.7
25	239	166	91.6	96.3	97.0	99.6	98.3	97.4	98.3	69.5
26	340	290	94.7	98.1	99.1	99.7	99.4	99.7	99.7	85.3
27	360	328	97.8	98.0	98.0	98.9	99.4	99.7	99.7	91.1
28	458	430	99.8	99.8	99.6	99.6	99.8	99.6	99.3	93.9
29	550	522	98.9	99.6	99.6	99.8	99.8	99.8	99.6	94.9
30	689	680	99.9	99.7	99.9	99.9	99.9	100.0	99.9	98.7
31	884	876	99.7	99.9	99.9	99.9	99.8	100.0	100.0	99.1
Overall (22–31)	3754	3402	97.1	98.9	99.1	99.5	99.7	99.6	99.4	90.6