Changes in maternal hemoglobin during pregnancy and birth outcomes

Table 5 Adjusted OR and 95% CI of Hb changes from early pregnancy for low birth weight, small for gestational age, and high placental ratio ^a

	LBW	SGA^b	High placental ratio^c
	Adjusted OR (95% CI)	Adjusted OR (95% CI)	Adjusted OR (95% CI)
Hb changes from early to mid-pregnancy ^d
Greatest reduction (Hb change < −1.7) (n = 675)	1.2 (0.74 to 1.9)	0.72 (0.44 to 1.2)	1.1 (0.74 to 1.5)
Intermediate reduction (−1.7 ≤ Hb change < −1.1) (n = 680)	Reference	Reference	Reference
Least reduction (Hb change ≥ −1.1) (n = 631)	1.3 (0.84 to 2.1)	1.6 (1.1 to 2.5)	0.59 (0.39 to 0.90)
P for trend	0.66	0.001	0.02
Hb changes from early to late pregnancy ^d
Greatest reduction (Hb change < −1.9) (n = 639)	0.77 (0.46 to 1.3)	0.38 (0.23 to 0.65)	1.7 (1.2 to 2.5)
Intermediate reduction (−1.9 ≤ Hb change < −1.0) (n = 689)	Reference	Reference	Reference
Least reduction (Hb change ≥ −1.0) (n = 658)	2.0 (1.3 to 3.1)	1.6 (1.04 to 2.3)	0.76 (0.49 to 1.2)
P for trend	<0.001	<0.001	<0.001

^aAdjusted for maternal age, parity, pre-pregnancy BMI, smoking, ART, fetal sex, MAP at early pregnancy, medical complications (hypertension, autoimmune disease, Basedow’s disease, hypothyroid disease), and Hb levels at early pregnancy.
^bSGA is defined as being below the 10^th percentile of the Japanese national reference.
^cHigh placental ratio is defined as being over the 90^th percentile of the sample population.
^dHb changes were calculated as Hb at mid- or late pregnancy – Hb at early pregnancy.
ART, artificial reproductive technology; CI, confidence interval; Hb, hemoglobin; LBW, low birth weight; MAP, mean arterial pressure; OR, odds ratio; SGA, small for gestational age.

ISSN: 1471-2393