Changes in maternal hemoglobin during pregnancy and birth outcomes

Table 3 Association between Hb levels at early, mid-, and late pregnancy and birth outcomes (n = 1986)

Birth outcome	Hb levels during pregnancy	Crude model		Model 1		Model 2
Birth outcome	Hb levels during pregnancy	Coefficient	95% CI	Coefficient	95% CI	Coefficient	95% CI
Birth weight (g)	Early pregnancy	−13.6	−32.0 to 4.8	−25.1*	−43.5 to −6.7	−18.1	−36.8 to 0.49
	Mid-pregnancy	−55.3**	−74.7 to −35.9	−63.4**	−82.6 to −44.2	−57.9**	−77.3 to −38.5
	Late pregnancy	−71.0**	−88.0 to −53.9	−75.9**	−92.8 to −59.1	−73.2**	−90.0 to −56.4
Z-score of birth weight	Early pregnancy	−0.0035	−0.050 to 0.043	−0.039	−0.086 to 0.0074	−0.028	−0.076 to 0.019
	Mid-pregnancy	−0.14**	−0.19 to −0.088	−0.16**	−0.21 to −0.11	−0.15**	−0.20 to −0.10
	Late pregnancy	−0.19**	−0.23 to −0.14	−0.20**	−0.24 to −0.16	−0.20**	−0.24 to −0.16
Placental weight (g)	Early pregnancy	2.1	−2.9 to 7.1	−1.0	−6.1 to 4.0	−0.55	−5.7 to 4.6
	Mid-pregnancy	−15.5**	−20.8 to −10.2	−17.7**	−23.0 to −12.4	−17.6**	−23.0 to −12.3
	Late pregnancy	−22.4**	−27.0 to −17.9	−23.3**	−27.9 to −18.7	−23.3**	−27.9 to −18.8
Placental ratio (x1000)	Early pregnancy	1.55*	0.20 to 2.9	1.2	−0.18 to 2.5	0.91	−0.48 to 2.3
	Mid-pregnancy	−1.8*	−3.2 to −0.35	−2.1*	−3.5 to −0.63	−2.4*	−3.9 to −0.93
	Late pregnancy	−3.1**	−4.4 to −1.9	−3.1**	−4.4 to −1.9	−3.3**	−4.6 to −2.0

*P < 0.05, **P < 0.001.
Model 1: adjusted for maternal age, parity, pre-pregnancy BMI, smoking, ART, fetal sex.
Model 2: adjusted for Model 1 + MAP at early pregnancy and medical complications (hypertension, autoimmune disease, Basedow’s disease, hypothyroid disease).
ART, artificial reproductive technology; CI, confidence interval; Hb, Hemoglobin; MAP, mean arterial pressure; Z-score, z-score of birth weight.

ISSN: 1471-2393