Intravenous iron for treatment of iron deficiency anemia during pregnancy and associated maternal outcomes

Figures & data

Table 1. Patient characteristics and outcomes by receipt of intravenous iron.

	IV Iron n = 944	No IV Iron n = 4110	p-value	OR (95% CI)	aOR^g (95% CI)
a. Baseline Characteristics
Maternal age ≥ 35 years	185 (19.6)	847 (20.6)	.49
Race/ethnicity			.01
Hispanic	303 (32.1)	1153 (28.1)
Black	305 (32.3)	1251 (30.4)
Non-Hispanic White	255 (27.0)	1324 (32.2)
Asian	40 (4.2)	207 (5.0)
Other	41 (4.3)	175 (4.3)
Commercial Insurance	388 (41.1)	1801 (43.8)	.22
Married	417 (44.2)	1946 (47.4)	.08
Pre-pregnancy BMI ≥30 kg/m^2	266 (28.2)	1085 (26.4)	.07
Nulliparous	308 (32.6)	1549 (37.7)	.01
Multifetal gestation	20 (2.1)	92 (2.2)	.82
Delivery estimated blood loss ≥ 1000 mL^a	65 (6.9)	229 (5.6)	.12
Cesarean delivery	300 (31.8)	1236 (30.1)	.30
Anticoagulation use^b	28 (3.0)	97 (2.4)	.28
Aspirin use^b	125 (13.2)	348 (8.5)	<.01
Fibroids	73 (7.7)	349 (8.5)	.45
b. Hematologic Indices
Antepartum hematocrit nadir <25%	87 (9.2)	117 (2.9)	<.01
Median antepartum hematocrit nadir, %	28.8 (27.1-30.3)	30.6 (29.2-31.7)	<.01
Median hematocrit at delivery admission, %	33.3 (30.3-35.9)	33.6 (31.0-36.1)	.01
Median change in hematocrit from nadir to admission, %	4.5 (1.85-7.20)	3.3 (0.90-5.60)	<.01
c. Patient outcomes
Maternal morbidity composite	68 (7.2)	206 (5.0)	<.01	1.47 (1.11–1.95)	1.37 (1.02–1.85)
Maternal transfusion^c	35 (3.7)	114 (2.8)
Hysterectomy^d	8 (0.9)	25 (0.6)
ICU admission^e	30 (3.2)	83 (2.0)
Maternal Mortality^f	0	1
Fetal or neonatal death	2 (0.2)	3 (0.1)	.24

Data are presented as n (%) or median (interquartile range).

BMI: body mass index; IV: intravenous, OR: odds ratio; CI: confidence interval; aOR: adjusted odds ratio.

^aBlood loss as estimated by the provider and recorded in the nursing electronic delivery record.

^bAs documented in electronic health records medication list as enoxaparin, fondaparinux, heparin or warfarin or aspirin.

^cMaternal transfusion is defined as red blood cell transfusion during delivery hospitalization.

^dHysterectomy during delivery admission.

^eAdmission within 30 days of delivery.

^fMaternal mortality within one year of delivery.

^gAdjusted for race/ethnicity, parity, aspirin use, delivery estimated blood loss, and hematocrit at delivery admission.

Table 2. Sub-analysis among women who received intravenous iron.

	≥ 5 doses of IVI n = 472	<5 doses of IVI n = 472	p value
a. Baseline Characteristics
Maternal age ≥ 35 years	117 (24.8)	68 (14.4)	<.01
Race/ethnicity			<.01
Hispanic	144 (30.5)	159 (33.7)
Black	123 (26.1)	182 (38.6)
Non-Hispanic White	163 (34.5)	92 (19.5)
Asian	17 (3.6)	23 (4.9)
Other	25 (5.3)	16 (3.4)
Commercial insurance	252 (53.4)	136 (28.8)	<.01
Married	250 (53.0)	167 (35.4)	<.01
Pre-pregnancy BMI ≥ 30 kg/m^2	127 (26.9)	139 (29.5)	.03
Nulliparous	165 (35.0)	143 (30.3)	.28
Multifetal gestation	9 (1.9)	11 (2.3)	.65
Delivery estimated blood loss ≥ 1000 mL^a	35 (7.4)	30 (6.4)	.52
Cesarean delivery	147 (31.1)	153 (32.4)	.67
Anticoagulation use^b	12 (2.5)	16 (3.4)	.44
Aspirin use^b	54 (11.4)	71 (15.0)	.10
Fibroids	44 (9.3)	29 (6.1)	.07
b. Hematologic Indices
Median antepartum hematocrit nadir, %	29.0 (27.2–30.4)	28.6 (27.0–30.3)	.19
Median hematocrit at delivery admission, %	34.5 (31.4–36.8)	32.1 (29.8–34.9)	<.01
Median change in hematocrit from nadir to admission, %	5.4 (2.7–8.0)	3.6 (1.2–6.2)	<.01

Data are presented as n (%) or median (interquartile range).

BMI: body mass index; IVI: intravenous iron; OR: odds ratio; CI: confidence interval; aOR: adjusted odds ratio.

^aBlood loss as estimated by the provider and recorded in the nursing electronic delivery record.

^bAs documented in electronic health record medication list as enoxaparin, fondaparinux, heparin or warfarin or aspirin.