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

Table 3 Haemoglobin dilution and the risk of stillbirth

	Cases	Controls	Odds Ratio (95 % Confidence Interval)
	n (%)	n (%)	Crude	Adjusted^a
Haemoglobin dilution during second trimester of pregnancy (g/l)
> 0.78	70 (26.7)	765 (33.8)	0.57 (0.42–0.78)	0.54 (0.39–0.74)
0.78–0.01	73 (27.9)	750 (33.2)	0.61 (0.45–0.83)	0.62 (0.45–0.85)
0.00 ≤	119 (45.4)	745 (33.0)	Reference	Reference
P for trend				<0.0001
Continuous	262 (100)	2,260 (100)	0.76 (0.63–0.92)	0.75 (0.62–0.90)
Haemoglobin dilution during pregnancy (g/l)
> 0.69	31 (20.0)	392 (33.1)	0.33 (0.21–0.51)	0.33 (0.21–0.52)
0.69–0.01	38 (24.5)	430 (36.3)	0.37 (0.25–0.56)	0.42 (0.27–0.66)
0.00 ≤	86 (55.5)	361 (30.5)	Reference	Reference
P for trend				<0.0001
Continuous	155 (100)	1,183 (100)	0.58 (0.45–0.74)	0.61 (0.46–0.80)

^aAdjusted for maternal age, maternal height, maternal BMI, parity, gestational age at first haemoglobin measurement, smoking status, husband’s profession, and region

ISSN: 1471-2393