Morbidity and mortality among very preterm singletons following fertility treatment in Australia and New Zealand, a population cohort study

Table 1 Demographics of very preterm singletons by mode of conceptions

	Spontaneous		HO		ART		AI		P value^a
	(20,530)		(216)		(953)		(54)
	#	%	#	%	#	%	#	%
Maternal age (years) Mean ± SD	28.87	±6.3	30.36	±4.9	34.64	±4.7	33.33	±4.7	<0.05^b
Gestational age (weeks) Mean ± SD	28.44	±2.5	28.12	2.4±	28.25	2.3±	28.19	2.3±	0.01
Aboriginal status
Yes	1274	6.2	4	1.9	10	1.0	0	0.0	<0.05
no	17079	83.2	186	86.1	830	87.1	52	96.3
Not stated	2177	10.6	26	12	113	11.9	2	3.7
Previous preterm birth
Yes	3928	19.1	24	11.1	78	8.2	7	13.0	<0.05
No	16506	80.4	192	88.9	874	91.7	47	87.0
Not stated	96	0.5	0	0.0	1	0.1	0	0.0
Previous perinatal death
Yes	1239	6.0	11	5.1	38	4.0	5	9.3	<0.05
No	19218	93.6	205	94.9	915	96.0	49	90.7
Not stated	73	0.4	0	0.0	0	0.0	0	0.0
Premature rupture of membranes
Yes	5243	25.5	44	20.4	246	25.8	10	18.5	0.301
No	15256	74.3	171	79.2	704	73.9	44	81.5
Not stated	31	0.2	1	0.5	3	0.3	0	0.0
Pregnancy inducted hypertension
Yes	3619	17.6	58	26.9	199	20.9	20	37.0	<0.05
No	16895	82.3	157	72.7	752	78.9	34	63.0
Not stated	16	0.1	1	0.5	2	0.2	0	0.0
Antepartum haemorrhage
Yes	5028	24.5	47	21.8	262	27.5	13	24.1	0.063
No	15488	75.4	168	77.8	689	72.3	41	75.9
Not stated	14	0.1	1	0.5	2	0.2	0	0.0
Antenatal steroid
None	2724	13.3	17	7.9	76	8	3.0	5.6	<0.05
Incomplete	5514	26.9	56	25.9	234	24.6	13	24.1
Complete	9377	45.7	111	51.4	468	49.1	33	61.1
More than 7 days	2548	12.4	31	14.4	156	16.4	5	9.3
Not stated	367	1.8	1	0.5	19	2.0	0	0.0
Gender of baby
Male	11279	54.9	122	56.5	517	54.2	33	61.1	0.98
Female	9233	45.0	94	43.5	436	45.8	21	38.9
Ambiguous	2	0.0	0	0.0	0	0.0	0	0.0
Not stated	16	0.1	0	0.0	0	0.0	0	0.0

ISSN: 1471-2393