The Prevalence of Anemia Among Pregnant Women at Booking in Enugu, South Eastern Nigeria

Abstract

Background

More than half of the pregnant women in the world have hemoglobin levels indicative of anemia. Knowledge of the current situation of the condition in our environment is necessary. This knowledge will motivate antenatal caregivers toward early detection and prompt management of anemia in pregnancy.

Aims

Our aim was to determine the prevalence of anemia among pregnant women at registration for antenatal care at a major tertiary healthcare center in Enugu, southeastern Nigeria.

Methods

This was a retrospective study of 530 normal pregnant women registered with the antenatal unit of the University of Nigeria Teaching Hospital (UNTH), Enugu, between January 1, 2005 and October 30, 2005. Data on the age, parity, gestational age at booking, interval between last confinement and last menstrual period in the index pregnancy, hemoglobin concentration at booking, and HIV status were obtained and analyzed.

Results

The mean gestational age at booking was 21.7 ± 7.1 weeks (range, 6–37). Two hundred fourteen (40.4%) of the women were anemic (hemoglobin [Hb] < 11.0 g/dL). The majority (90.7%) of these anemic patients were mildly anemic, whereas 9.3% were moderately anemic. There was no case of severe anemia (Hb < 7.0 g/dL). The prevalence of anemia at booking was significantly higher in those who registered for antenatal care in the third trimester than in those who registered in the second trimester, and in HIV-positive pregnant women than in HIV-negative ones (P = .00). The patients' age, parity, and the interval between the last confinement and the index pregnancy had no significant relationship with the hemoglobin concentration of pregnant women at booking (P > .05).

Conclusion

The prevalence of anemia in pregnancy at booking is still high in Enugu. Preconception care, including iron and folic acid supplementation, is advocated to reduce this problem. Early antenatal booking and improved antenatal care are also necessary for early diagnosis and treatment of the condition. All would ensure safe motherhood.

Introduction

Anemia in pregnancy is defined by the World Health Organization (WHO) as a hemoglobin concentration below 11 g/dL.[1] It continues to be a major health problem in many developing countries and is associated with increased rates of maternal and perinatal mortality, premature delivery, low birth weight, and other adverse outcomes.[2,3] More than half of the pregnant women in the world have hemoglobin levels indicative of anemia.[1] Although only 15% of pregnant women are anemic in developed countries,[4] the prevalence of anemia in developing countries is relatively high (33% to 75%).[1,3, 5–7] The most common cause of anemia in pregnancy worldwide is iron deficiency.[3] The predisposing factors include grandmultiparity, low socioeconomic status, malaria infestation, late booking, HIV infection, and inadequate child spacing – among others.[8–11]

Because anemia is the most frequent maternal complication of pregnancy, antenatal care should therefore be concerned with its early detection and management.[12] Therefore, the objective of this study was to determine the prevalence of anemia among pregnant women at registration for antenatal care at a major tertiary care hospital in Enugu, southeastern Nigeria.

Materials and Methods

This was a retrospective study of normal pregnant women who registered with the antenatal unit of the University of Nigeria Teaching Hospital (UNTH) Enugu between January 1, 2005 and October 30, 2005.

UNTH Enugu is the pioneer teaching hospital in southeastern Nigeria. It is located within Enugu city, which was the capital of the Igbo-speaking southeastern region of Nigeria and currently the capital of the recently created Enugu state. The hospital offers both primary and specialized health services for the people of Enugu and its environment. It still serves as a major referral center for the southeastern and parts of the middle-belt regions of Nigeria.

A sampling frame was made from a register of all pregnant women registered for antenatal service at the hospital within the study period. Using a systematic sampling method, every first out of 2 registered names was selected for the study. Five hundred thirty names were selected and their case records retrieved from the medical records department of the hospital, following approval by the hospital authorities. Data were obtained with respect to age, parity, gestational age at booking, interval between last confinement and last menstrual period, hemoglobin concentration at booking, and HIV status. To qualify for this study, the case must be a singleton pregnancy with no complaint of vaginal bleeding. At the UNTH, Enugu, hemoglobin concentration is usually determined by very well-trained laboratory scientists using the colorimetric method. Data were analyzed using the Statistical Package for Social Sciences (SPSS) software version 11 (SPSS Inc; 2001). There was cross-tabulation of various variables: age, parity, interval between last confinement and last menstrual period, HIV status, and gestational age at booking against hemoglobin concentration profile. Pearson's chi-square test was used to evaluate the effect of these variables on the hemoglobin concentration profile at the 95% confidence level.

A hemoglobin value of less than 11.0 g/dL was considered to be anemia in pregnancy. The degrees of anemia studied were mild anemia (9.0–10.9 g/dL), moderate anemia (7.0–8.9 g/dL), and severe anemia (less than 7.0 g/dL).

Results

All 530 pregnant women were married and had a mean age of 30.2 ± 5.2 years. Five hundred twenty (98.1%) were of the Igbo tribe. The 10 others were made up of 4 (0.8%) Yorubas; 2 (0.4%) Idomas; and 1 (0.2%) each of Urhobo, Ishan, Ibibio, and Igala. The mean gestational age at booking was 21.7 ± 7.1 weeks (range, 6–37). One hundred eighty-seven (35.3%) of the study population were nulliparous, 257 (48.5%) multiparous, whereas 86 (16.2%) were grandmultiparous. For the multiparous and the grandmultiparous women, the mean interval between the last confinement and the index pregnancy was 2.2 ± 1.8 years.

Two hundred fourteen (40.4%) of the study population were anemic (hemoglobin [Hb] < 11g%) at booking, out of which 194 (90.7%) were mildly anemic and 20 (9.3%) were moderately anemic. No case of severe anemia was noted. The HIV status of 8 (1.5%) of the 530 cases was not indicated. Twenty-seven (5.2%) of the remaining cases were positive for HIV-1 and HIV-2 infection. The prevalence of anemia at booking increased significantly with increasing gestational age at booking (P = .01) and with HIV-positive status (P = .00). About 26.5% of the women who booked in the first trimester were anemic compared with 41.8% and 46.0% for second and third trimesters, respectively (Table 1). Twenty (74.1%) of 27 mothers who were HIV-positive were anemic. Table 2 shows that the prevalence of anemia at booking increased with parity but the relationship was not statistically significant (P = .06). Patients' age and birth interval did not affect hemoglobin concentration of pregnant women at booking (P > .05).

Table 1.

Prevalence of Anemia by Trimester

	Anemia Present?
	No	Yes	Total
First trimester	61 (73.5%)	22 (26.5%)	83 (100.0%)
Second trimester	188 (58.2%)	135 (41.8%)	323 (100.0%)
Third trimester	67 (54.0%)	57 (46.0%)	124(100.0%)
Total	316 (59.6%)	214 (40.4%)	530 (100.0%)
chi-square = 8.51	Degrees of freedom = 2		P = .01

Table 2.

Prevalence of Anemia by Parity Group

	Anemia Present?
	No	Yes	Total
Nulliparous	124 (66.3%)	63 (33.7%)	187 (100.0%)
Multiparous	146 (56.8%)	111 (43.2%)	257 (100.0%)
Grandmultiparous	46 (53.5%)	40 (46.5%)	86 (100.0%)
Total	316 (59.6%)	214 (40.4%)	530 (100.0%)
chi-square = 5.66	Degrees of freedom = 2		P = .06

Discussion

The prevalence of anemia in pregnancy of 40.4% in this study was consistent with data observed in other studies in developing countries.[7,8,11] The prevalence was greater than 8.8% but less than 67.4% observed in the same center in 1979[13] and 1990,[6] respectively. The very low incidence of anemia in the 1979 study might have been due to the use of a hemoglobin concentration of 10 g/dL as the definition of anemia in pregnancy. Although this study established a marked reduction in the prevalence of anemia in pregnancy when compared with the 1990 review, which used the same criterion, the explanation is difficult and cannot be easily attributed to an improvement in the health status of women of reproductive age group in the locality. Expectedly, most of the anemic patients (90.7%) in this study were of the mild variety, whereas 9.8% were moderately anemic. Incidentally, as in other recent studies from southeastern Nigeria[10,11] and Ibadan, Western Nigeria,[12] no case of severe anemia was noted, unlike in Shagamu, Western Nigeria,[14] where 0.7% of the anemic pregnant women were severely anemic. Also, in Southern Malawi, 3.6% of anemic pregnant women were of the severe variety (Hb < 7.0 g/dL).

In West Africa, anemia in pregnancy results from multiple causes, including iron and folate deficiency; malaria and hookworm infestation; infections, such as HIV; and hemoglobinopathies.[15,16] Pica has been identified as a risk factor for anemia in pregnancy.[17] This could be applicable to this environment in which a special type of clay of the kaolinite group (called “nzu” in Igbo language) is easily accessible in the open markets, and some pregnant women crave it. Further studies are required to explain this craving and its effect on patients' nutrition and anemia in pregnancy.

Iron deficiency is believed to be the most common cause of anemia in pregnancy;[3] therefore, anaemia in a normal pregnant woman in this environment is usually attributed to iron deficiency, and successful treatment is often achieved with iron and folic acid without further investigations. This may explain why patients' case notes reviewed in this study could not give further information on the investigations done to identify the specific causes of the anemia. Available basic investigations that should have been carried out in these patients include blood-film microscopy for red blood cell morphology and ring form of Plasmodium falciparum and stool analysis for helminths, especially hookworm. Furthermore, with the mean gestational age at booking of 22 weeks in this study, physiologic hemodilution in pregnancy[18] may explain the increased prevalence of mild anemia.

As in a previous study from the center,[6] maternal age and parity had no statistical relationship with the prevalence of anemia at booking. Both studies observed that anemia at booking increased with gestational age, which is consistent with findings in similar studies[7,8] but variant with a related study in Zimbabwe,[19] which found that gestational age and season were not significant predictors of hemoglobin concentration. With the current HIV/AIDS epidemic in Nigeria,[20] unlike in 1990 when the previous review was done, this study has gone further to identify a significant statistical relationship between HIV infection and a high prevalence of anemia in pregnancy. This increased prevalence of anemia among pregnant women living with HIV/AIDS may be explained by the finding that HIV infection is associated with lower serum folate and serum ferritin in pregnancy.[19]

This study was limited by its retrospective nature and reliance on case notes with the attendant documentation inadequacies. Therefore, we could not study the specific causes of anemia in pregnancy in this environment. A prospective study with emphasis on the etiology of anemia in pregnancy is recommended.

We conclude that the prevalence of anemia at booking is still high in Enugu. The results suggested that anemia predates the pregnancy in the majority of cases. Hence, preconception care, including iron and folic acid supplementation, is advocated to reduce this problem. During pregnancy, efforts should be geared toward the early detection and treatment of anemia before delivery. Also, medical staff managing pregnant women should endeavor to investigate anemic pregnant women further in order to identify the etiology whenever possible, despite commencing the usual treatment with iron and folate. All of these efforts would help to ensure safe motherhood and achieve the relevant targets of the Millennium Development Goals.