Table 4. Perinatal characteristics and outcomes in the patient groups and the control group.

	Fracture group		Fusion surgery group		Control group
Total number	2301		632		1154469
	n	%	n	%	n	%
LBW* < 2500g	80	3.5	24	3.8	34 402	3.0
Preterm < 37 + 0 gestational weeks	115	5.0	46	7.3	53 019	4.6
Perinatal mortality**	9	0.4	5	0.8	6158	0.5
1 minute Apgar score ≤ 6	333	14.5	85	13.4	157 131	13.6
Neonatal intensive-care unit	281	12.2	86	13.6	115 558	10.0
Discharged from hospital during the first week	2143	93.1	589	93.2	1 084 983	94.0

*LBW = low birthweight.

**perinatal mortality includes still births and deaths before the age of seven days