Prevalence of anemia in pregnancy and its association with birth weight

retrospective longitudinal observational study in a cohort of 370 pregnant women. Anthropometric, biochemical, ginecobstetric and sociodemographic data of both mothers and newborns were evaluated. The results of maternal erythrocyte indices were analyzed and contrasted with newborns anthropometrical data.

Results:

the mean age of the pregnant women was 27±6 years, with a mean gestational age of 32±6 weeks at the assessment moment, 56.2% were overweight. The prevalence of anemia was 28.6%. 47.2% women with anemia and 36% women without anemia had low birth weight/very low birth weight newborns (p=0.009). Of the children born to mothers with iron deficiency anemia, 20% had low birth weight and 15% very low birth weight. 54.3% newborns with global undernutrition or at risk of developing it were born to women with underweight(p=0.046), in addition, the higher the maternal weight, the lower the number of term newborns with risk of short height (p<0.001).

Conclusions:

there is relationship between the anemia, the maternal nutritional status and the birth weight.

Key words
Anemia; Birth weight; Pregnancy; Maternal nutrition

Sociodemographic, anthropometric, biochemical and clinical characteristics of the mother.
Variable	N=370	%e
Mother age (years), $\bar{x}$ ± SD	27.0 ± 6
Educative level
Primary	92	24.9
Seconday	108	29.2
Technical	56	15.1
Technological	19	5.1
Universitary	32	8.6
Especialization	3	0.8
None	60	16.2
Affiliation to Colombian health regimen
Contributive	187	50.5
Subsidized	168	45.4
Linked	4	1.1
No coverage	11	3.0
Parity
Primiparity	133	35.9
Second pregnant	96	25.9
Third pregnant	64	17.3
Multiparity	77	20.8
Civil status
Married	72	19.5
Single	99	26.8
Common-law union	198	53.5
Separated	1	0.3
Type of delivery
Spontaneous	140	37.8
Cesarean section	230	62.2
Maternal weight (kilos), $\bar{x}$ ± SD	73.4 ± 14.8
Maternal height (meters), $\bar{x}$ ± SD	1.59 ± 0.1
Maternal BMI (Kg/m²), $\bar{x}$ ± SD	29.1 ± 5.4
Maternal BMI classification
Underweight	59	15.9
Normal	103	27.8
Overweight	124	33.5
Obesity	84	22.7
Maternal gestational age at the time of anemia diagnosis (years), $\bar{x}$ ± SD	32.6 ± 6.2
Trimester of pregnancy
First trimester	7	1.9
Second trimester	50	13.5
Third trimester	313	84.6
Hemoglobin (mg/dL), $\bar{x}$ ± SD	11.5 ± 1.6
Hematocrit (%), $\bar{x}$ ± SD	35.8 ± 4.6
Anemia
Yes	106	28.6
No	264	71.4

Relationship between the presence of maternal anemia, birth weight, type of delivery and individual anthropometric indicators of the newborn.
Variables	Gestational anemia				OR (CI95%)	p
Variables	Yes (N=106)		No (N=264)		OR (CI95%)	p
Length NB (cm), Me (RIQ)^* * U de Mann Whitney;	46 (42-49)		w47 (44-49)		-	0.223
Weight NB (gr), Me (RIQ)^* * U de Mann Whitney;	2585 (1971-3181)		2685 (2120-3200)		-	0.223
Birth weight^ Pearson Chi Square; p<0.05.	n=106	%	n=264	%
Adequate	53	50.0	150	56.8	Ref
Low weight	34	32.1	82	31.1	1.17 (0.70-1.95)	0.536
Very low weight	16	15.1	13	4.9	3.48 (1.57-7.72)	0.001
Extreme low weight	1	0.9	11	4.2	0.25 (0.03-2.04)	0.167
Macrosomic	2	1.9	8	3.0	0.70 (0.14-3.43)	0.666
Type of delivery^ Pearson Chi Square; p<0.05.	n=106	%	n=264	%
Full-term	52	49	157	59.5	1.52 (0.96-2.39)	0.067
Preterm	54	51	107	40.5	1.52 (0.96-2.39)	0.067
Preterm NB (length/age)^ Pearson Chi Square; p<0.05.	n=54	%	n=107	%
Adequate	45	83.3	97	90.7	Ref
Low	4	7.4	6	5.6	1.43 (0.38-5.34)	0.586
IGR	5	9.3	4	3.7	2.69 (0.69-10.5)	0.14
Full-term NB (length/age)^ Pearson Chi Square; p<0.05.	n=52	%	n=157	%
Adequate	38	73.1	103	65.6	Ref
Risk of low legth	8	15.4	28	17.8	0.77 (0.32-1.84)	0.563
Low length	6	11.5	26	16.6	0.62 (0.23-1.63)	0.336
Preterm NB (weight/age)^ Pearson Chi Square; p<0.05.	n=54	%	n=107	%
Adequate	44	81.5	86	80.4	Ref
Low	5	9.3	8	7.5	1.22 (0.37-3.95)	0.738
IGR	1	1.9	4	3.7	0.48 (0.05-4.50)	0.519
Excess	4	7.4	9	8.4	0.86 (0.25-2.97)	0.822
Full-term NB (weight/age)^ Pearson Chi Square; p<0.05.	n=49	%	n=144	%
Adequate	35	71.4	94	65.3	Ref
Risk of global malnutrition	10	20.4	36	25.0	0.74 (0.33-1.66)	0.472
Global malnutrition	4	8.2	14	9.7	0.76 (0.23-2.48)	0.658
Full-term NB (weight/length)^ Pearson Chi Square; p<0.05.	n=52	%	n=157	%
Adequate	37	71.2	90	57.3	Ref
Risk of acute undernutrition	8	15.4	20	12.7	0.97 (0.39-2.40)	0.952
Moderate acute undernutition	1	1.9	4	2.5	0.60 (0.06-5.62)	0.658
Severe acute undernutrition	2	3.8	4	2.5	1.21 (0.21-6.92)	0.825
Risk of overweight	1	1.9	29	18.5	0.08 (0.01-0.63)	0.003
Overweight	1	1.9	4	2.5	0.6 (0.06-5.62)	0.658
Obesity	2	3.8	6	3.8	0.81 (0.15-4.20)	0.802

Relationship between maternal type of anemia, birth weight of the newborn and type of delivery.
Neonatal variables	Type of maternal anemia
Neonatal variables	Normocytic normochromic (N=51)	Normocytic hypochromic (N=21)	Normocytic hyperchromic (N=13)	Microcytic hypochromic (N=20)	Macrocytic Hyperchromic (N=1)	p
Length NB (cm), Me (RIQ)	46 (43-49)	46 (41-49)	47 (37-49)	48 (42-50)	35 (35-35)	0.287^* * Kruskal Wallis;
Weight NB (gr), Me (RIQ)	2,430 (1,975-3,000)	2,680 (1,937-3,207)	2,700 (1,412-2,965)	2,920 (1,990-3,615)	1,020 (1,020-1,020)	0.319^* * Kruskal Wallis;
Birth weight, n (%)						0.045^ Pearson Chi Square; p<0.05.
Adequate	23 (45.1)	11 (52.4)	8 (61.5)	11 (55.0)	0
Low weight	22 (43.1)	6 (28.6)	2 (15.4)	4 (20.0)	0
Very low weight	6 (11.8)	4 (19.0)	2 (15.4)	3 (15.0)	1 (100.0)
Extreme low weight	0	0	1 (7.7)	0	0
Macrosomic	0	0	0	2 (10.0)	0
Type of delivery, n (%)						0.274^ Pearson Chi Square; p<0.05.
Preterm	28 (54.9)	13 (61.9)	5 (38.5)	7 (35.0)	1 (100.0)
Full-term	23 (45.1)	8 (38.1)	8 (61.5)	13 (65.0)	0

Relationship between maternal nutritional status, individual anthropometric indicators of the newborn and birth weight.
Neonatal variables	Maternal BMI				p
Neonatal variables	Underweight	Normal	Overweight	Obesity	p
Preterm NB (length/age), n (%)	n=23	n=43	n=57	n=38	0.179^* * Pearson Chi Square; p<0.05.
Adequate	19 (82.6)	38 (88.4)	53 (93.0)	32 (84.2)
Low	2 (8.7)	5 (11.6)	1 (1.8)	2 (5.3)
IGR	2 (8.7)	0	3 (5.3)	4 (10.5)
Full-term NB (length/age), n (%)	n=36	n=60	n=67	n=46	<0.001^* * Pearson Chi Square; p<0.05.
Adequate	13 (36.1)	42 (70.0)	50 (74.6)	36 (78.3)
RLL	14 (38.9)	12 (20.0)	9 (13.4)	1 (2.2)
Low length	9 (25.0)	6 (10.0)	8 (11.9)	9 (19.6)
Preterm NB (weight/age), n (%)	n=23	n=43	n=57	n=38	0.494^* * Pearson Chi Square; p<0.05.
Adequate	17 (73.9)	36 (83.7)	48 (84.2)	29 (76.3)
Low	4 (17.4)	3 (7.0)	4 (7.0)	2 (5.3)
IGR	1 (4.3)	2 (4.7)	0	2 (5.3)
Excess	1 (4.3)	2 (4.7)	5 (8.8)	5 (13.2)
Full-term NB (weight/age), n (%)	n=35	n=57	n=58	n=43	0.046^* * Pearson Chi Square; p<0.05.
Adequate	16 (45.7)	39 (68.4)	42 (72.4)	32 (74.4)
RGM	12 (34.3)	15 (26.3)	12 (20.7)	7 (16.3)
Global malnutrition	7 (20.0)	3 (5.3)	4 (6.9)	4 (9.3)
Full-term NB (weight/length), n (%)	n=36	n=60	n=67	n=46	0.221^* * Pearson Chi Square; p<0.05.
Adequate	22 (61.1)	39 (65.0)	38 (56,7)	28 (60.9)
RAU	8 (22.2)	8 (13.3)	7 (10.4)	5 (10.9)
Moderate acute undernutition	0	1 (1.7)	3 (4.5)	1 (2.2)
Severe acute undernutrition	0	4 (6.7)	0	2 (4.3)
RO	4 (11.1)	6 (10.0)	15 (22.4)	5 (10.9)
Overweight	0	0	2 (3.0)	3 (6.5)
Obesity	2 (5.6)	2 (3.3)	2 (3.0)	2 (4.3)
Birth weight, n (%)					0.951^* * Pearson Chi Square; p<0.05.
Adequate	32 (54.2)	57 (55.3)	67 (54.0)	47 (56.0)
Low weight	23 (39.0)	30 (29.1)	38 (30.6)	25 (29.8)
Very low weight	3 (5.1)	10 (9.7)	10 (8.1)	6 (7.1)
Extreme low weight	1 (1.7)	3 (2.9)	5 (4.0)	3 (3.6)
Macrosomic	0	3 (2.9)	4 (3.2)	3 (3.6)

Relationship between birth weight, maternal anthropometry and the presence of maternal anemia.
Maternal anemia	Maternal BMI	Birth weight of the newborn					p^* * Pearson Chi Square; p<0.05.
Maternal anemia	Maternal BMI	Adequate	Low weight	Very low weight	Extreme low weight	Macrosomia	p^* * Pearson Chi Square; p<0.05.
Yes n (%)	BMI (Kg/m²)	n=53	n=34	n=16	n=1	n=2	0.422
	Underweight	9 (17.0)	11 (32.4)	2 (12.5)	0	0
	Normal	16 (30.2)	8 (23.5)	5 (31.3)	1 (100.0)	2 (100.0)
	Overweight	13 (24.5)	8 (23.5)	6 (37.5)	0	0
	Obesity	15 (28.3)	7 (20.6)	3 (18.8)	0	0
No n (%)	BMI (Kg/m²)	n=150	n=82	n=13	n=11	n=8	0.949
	Underweight	23 (15.3)	12 (14.6)	1 (7.7)	1 (9.1)	0
	Normal	41 (27.3)	22 (26.8)	5 (38.5)	2 (18.2)	1 (12.5)
	Overweight	54 (36.0)	30 (36.6)	4 (30.8)	5 (45.5)	4 (50.0)
	Obesity	32 (21.3)	18 (22.0)	3 (23.1)	3 27.3)	3 (37.5)

Instituto de Medicina Integral Prof. Fernando Figueira Rua dos Coelhos, 300. Boa Vista, 50070-550 Recife PE Brasil, Tel./Fax: +55 81 2122-4141 - Recife - PR - Brazil
E-mail: revista@imip.org.br

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[1] Associated Editor: Aurélio Costa