Table 2.

Season of birth associations with low birth weight (< 2.5 Kg) in the UK Biobank study.

	All (N = 25,054 cases)		Men (N = 7,072 cases)		Women (N = 17,982 cases)
	OR (95% CI)	P	OR (95% CI)	P	OR (95% CI)	P
Spring	1.03 (1.00–1.06)	5.0E–02	1.00 (0.95–1.06)	9.3E–01	1.04 (1.01–1.08)	2.4E–02
Summer	0.90 (0.88–0.93)	7.0E–11	0.91 (0.86–0.96)	1.0E–03	0.90 (0.87–0.93)	1.7E–08
Autumn	0.92 (0.89–0.95)	1.8E–07	0.97 (0.91–1.02)	2.6E–01	0.90 (0.87–0.93)	4.0E–08
Winter	1.16 (1.13–1.19)	1.7E–22	1.13 (1.07–1.19)	1.3E–05	1.17 (1.13–1.21)	1.3E–18
Feb vs Sept	1.23 (1.15–1.32)	4.4E–10	1.13 (1.00–1.28)	4.5E–02	1.28 (1.18–1.38)	9.4E–10

Spring (March–April–May), Summer (June–July–August), Autumn (September–October–November) and Winter (December–January–February).