Maternal haemoglobin concentrations before and during pregnancy and stillbirth risk: a population-based case-control study

Table 4 Haemoglobin dilution and risks of preterm and term stillbirth

	Preterm stillbirth			Term stillbirth
	Cases (n = 81)	Controls (n = 2,260)	Odds ratio^a (95 % CI)^b	Cases (n = 181)	Controls (n = 2,105)	Odds ratio^a (95 % CI)^b
	n (%)	n (%)	n (%)	n (%)	n (%)	Odds ratio^a (95 % CI)^b
Haemoglobin dilution during second trimester of pregnancy (g/l)
> 0.78	22 (27.6)	765 (33.8)	0.49 (0.28–0.84)	48 (26.5)	716 (34.0)	0.55 (0.38–0.81)
0.78–0.01	20 (24.7)	750 (33.2)	0.50 (0.28–0.87)	53 (29.3)	701 (33.3)	0.67 (0.46–0.97)
0.00 ≤	39 (48.1)	745 (33.0)	Reference	80 (44.2)	688 (32.7)	Reference
P for trend			<0.01			<0.01
Continuous	81 (100)	2,260 (100)	0.75 (0.54–1.06)	181 (100)	2,105 (100)	0.75 (0.61–0.93)

^aAdjusted for: maternal age, maternal height, maternal BMI, parity, gestational age at first haemoglobin measurement, history of smoking, husband’s profession, and region
^bOR denotes Odds ratios and CI denotes confidence intervals

ISSN: 1471-2393