Iron is one of the most essential microelements in human body, due partly to
its need in many haemoproteins (Murray et al., 2003).
Normally, human contain about 4 g of iron in their entire body. Out of this
amount, 65% occur in haemoglobin, while a half of the remainder is stored chiefly
as ferritin and haemosiderin in the liver, spleen and bone marrow. The iron
in these molecules is available for fresh haemoglobin synthesis. The rest of
the non-erythropoietic iron is available in myoglobin, cytochromes and various
enzymes (Rang et al., 2003).
Pregnancy is a normal physiological process involving progressive changes in
mother and foetus. During this period, maternal physiological adjustments impose
additional demands for nutrients requirements, including iron. For a sustainable
healthy gestation, pregnant women need 3-4 times the iron requirement of the
non-pregnant women (Zavaleta et al., 2000).
This essentially sustains the nutritional status of the mother and her ability
to transfer nutrients to the foetus at the appropriate time during pregnancy
(Jackson et al., 2003). A shortfall of iron,
in any form, from this requirement likely generates Gestational Iron Deficiency
(GID) (Godfrey et al., 1991) and the consequent
anaemia due to iron deficiency erythropoiesis (Seshadri,
Iron deficiency, with or without anaemia, is reported to affect about 25% of
the poorer pregnant women even in developed countries like USA (Beard,
1994). The present study therefore, looks into and compares the iron status
of pregnant urban and rural settlers in Ebonyi State.
MATERIALS AND METHODS
Study site and setting: For this study, two hospitals were selected B Federal Teaching Hospital, Abakaliki (FETHA) and St Vincent Hospital, Ndubia (SVHN). The two Hospitals represent the urban and rural divisions of the study respectively. Three hundred and seven (200 from FETHA and 107 from SVHN) pregnant women attending antenatal clinics in the two hospitals were recruited for the study. The selection was done by simple random method.
Sample collection: At recruitment, the obstetric and demographic data of the participants were collected through a semi-structured questionnaire. The maternal anthropometrics were also taken. Through the health experts, 5.0 mL of non-fasting venous blood sample was collected from each participant at the antenatal care (ANC) halls of the study hospitals, using dry disposable plastic syringes. From the sample, 2.0 mL was dispensed into EDTA bottle and used for haematological studies the same day; while the remaining 3.0 mL was dispensed into plane glass test tube and allowed to clot, from where serum was extracted after centrifugation. The serum was transported frozen to Kogi State University, Ayimgba where the serum iron level was assessed.
Determination of Haemoglobin (HB) concentration: Haematological study
was done with Drabkins method according to Cheesbrough
(2000). It is based on the principle that haemoglobin is oxidized to methaemoglobin
by potassium ferricyanide which reacts with cyanide ions of potassium cyanide
to form cyanmethaemoglobin whose absorbance is measured at 540 nm. Haemoglobin
concentration was then estimated with the help of cyanmethemoglobin curve. Samples
were determined in triplicates and their average taken as the final value. Gestational
Hb level <11 g dL-1 was considered anaemic (WHO/UNICEF/UNU,
Determination of serum iron level: The method of atomic absorption (flame)
spectrometry, according to Wojck et al. (2009),
was employed to assess the serum iron level. The sample was wet mineralized
and hot dissolved in nitric acid solution [1 mL of serum+10 mL solution of H2SO4+HNO3
(1:1) and heated]. The iron level in the cleared solution (resulted mineralizate)
was read in atomic absorption spectrometer in three replicates, which the mean
was considered the final value. Iron level <10 μmol L-1 was
Data analysis: One way ANOVA, students t-test and Pearsons correlation were used for basic statistics, with statistical significance at 95% confidence limit (p<0.05). All statistical analysis was done using the computer software, AStatistical Programme for Social Sciences@ (SPSS for windows, version 15.0).
Ethical approval: The study was approved by the Research and Ethics
Committee of the hospitals and also by Ebonyi State University, Abakaliki, Nigeria,
under which the research was performed. Study protocols for the use of human
subjects were strictly adhered to in accordance with the international guidelines
for human experimentation in clinical research (WMA, 2000).
During the blood sampling, one out of the 200 urban pregnant women recruited
for the study refused to donate her blood sample (for her reserved reason(s)).
|| Mean characteristics of the subjects
|Variables with superscripts a and b were significant at p<0.001
and p<0.05, respectively (t-test used). N: Population size
|| Serum iron status of the pregnant women
In the rural sampling also, two were dropped along the line on health ground,
one of the blood samples was found clotted during screening (for [Hb]) and one
did not indicate her age; while seven of the serum samples were lost along the
line due to cracks on the vials and consequent contamination with the ice.
In Table 1, the maternal characteristics of the rural pregnant women were compared to the urban counterparts. Apart from the mean maternal age, all other parameters were significantly different from those of the urban ones. The mean maternal age of the rural women (27.3"6.15 years) has very close comparison to that of the urban women (27.3"4.61 years). The mean gestational age (24.9"5.77 weeks) and the mean serum iron level (16.4"18.1 μmol L-1) of the rural women were significantly (p<0.05) higher than those of the urban counterparts (21.9"3.12 weeks and 10.0"8.07 μmol L-1, respectively). Mean [Hb] (9.78"1.23 g dL-1) and BMI (24.5"3.15 kg m-2) of the rural pregnant women were significantly (p<0.05) lower than those of the urban subjects 10.2"1.37 g dL-1 and 27.3"3.94 kg m-2, respectively.
From Fig. 1, it showed that gestational iron deficiency (GID) and the consequent Iron Deficiency Anaemia (IDA) were significantly (p<0.01) more prevalent in the urban population (65.3, 47.5%, respectively) than in their rural counterparts (48.5, 41.9%, respectively).
|| Influence of maternal age on the prevalence of GID and IDA
|*%GID/%IDA: Urban (p = 0.234/0.134), rural (p = 0.485/0.670)-Pearsons
χ2 used. Matage: Maternal age
|| Influence of gestational age on the prevalence of GID and
|*%GID/%IDA: Urban (p = 0.570/0.777), Rural (p = 0.306/0.346)-Pearsons
χ2 used. Gesage: Gestational age
In the urban sub-group, the maternal age 20-24 years ranked lowest in the mean serum Fe level (8.31"6.85 μmol L-1) and higher prevalence of GID (75.6%) and then ranked next to 35-39 years age group (which ranked highest with 58.3%) in prevalence of IDA, though there was no statistical significance in each case (Table 2). In the rural counterparts, those 30 years of age and above showed higher mean serum Fe than the younger women, while the age groups 20-24 years and >30 years indicated higher prevalence of GID than the other groups but there was no significant difference in each case. The age groups below 24 years and above 39 years showed higher prevalence of IDA, which was not statistically significant still.
In Table 3 is the influence of gestational age on the prevalence
of GID and IDA. All the urban subjects were, more or less, beyond the 1st trimester
stage. The mean serum Fe level and the prevalence of GID among the urban and
rural sub-groups did not show any significant relationship with the gestational
age of the pregnant women.
|| Influence of parity on the prevalence of GID and IDA
|*%GID/%IDA: Urban (p = 0.283/0.102), Rural (p = 0.241/0.325)-Pearsons
Neither was there any significant relationship between the gestational age
of the subjects and the prevalence of IDA. However, in the rural subgroup the
women within the gestational age of 12-17 weeks and those >35 weeks were
at the lowest prevalence level of GID (25.0%). The lowest prevalence level of
IDA was also obtained from >35 weeks gestational age women (16.7%), followed
by 12-17 weeks gestational age women (20.0%). On the other hand, the highest
prevalence level of both GID (55.6%) and IDA (36.8%) were shown on the 18-23
weeks gestational age women.
From the result in Table 4, grand multiparous (parity >3) urban subgroup showed highest mean serum Fe level (11.4"9.82 μmol L-1), while highest prevalence of GID (75.6%) was observed in the primiparous women. In the rural counterparts, the mean serum Fe level peaked on the grand multiparous women also (20.5"23.3 μmol L-1), while highest prevalence of GID (65.4%) was rather shown in primigravida women. Neither of the subgroups showed statistical significance (p>0.05) based on parity. Highest prevalence of IDA (61.1%) was observed in the multiparous (parity = 3) urban women, followed by the primiparous ones (48.9%); while in the rural counterpart, higher prevalence of IDA was identified in the primigravida (60.7%), with the grand multiparous women (parity>3) showing least prevalence (28.6%), though none of the cases was statistically insignificant.
The result in Table 5 showed that the BMI of the pregnant
women had no significant influence on either the mean serum Fe level or the
prevalence of GID in each case. In the urban sub-group however, there was a
direct relationship, though statistically insignificant (p>0.05), between
the BMI grouping and the mean serum Fe level. The mean serum Fe level increased
alongside the energy status classification of the subjects; with the severely
malnourished having the least value (7.74 μmol L-1) and the
obese women the highest value (10.5"8.85 μmol L-1).
|| Influence of BMI of the subjects on the prevalence of GID
|*%GID/%IDA: Urban (p = 0.060/0.960), Rural (p = 0.637/0.637)-Pearsons
χ2 used Severe and moderate refer to the extent of protein
|| Influence of maternal occupation on the prevalence of GID
|*%GID/%IDA: Urban (p = 0.915/0.409), Rural (p = 0.286/0.168)-Pearsons
χ2 used, H/W: House wives, C/S: Civil servants
In the rural sub-group, such direct relationship seems to exist between the
maternal BMI and GID, but not with the mean serum Fe level and the prevalence
of IDA. In the urban sub-group, lower prevalence of IDA (33.3%) was identified
from the moderately malnourished and the obese women (43.9%). In the rural counterparts,
such was shown by the normal (42.2%) and overweight (30.0%) women but were all
statistically insignificant (p>0.05).
Table 6 presents the effect of the occupation of the pregnant
women on their Fe status. The occupation of the women did not show any significant
effect on the Fe status of the subjects. However, the urban women who engaged
in farming showed the highest mean serum Fe level (13.1"7.20 μmol L-1)
and lowest prevalence of GID (50.0%), but highest prevalence of IDA (50.0%),
which equals that of the house wives (H/W). Students and civil servant (C/S)
showed higher prevalence of GID but lower incidence of IDA than the rest. In
the rural sub-group also, the farmers showed the highest mean serum Fe level
(20.0"23.2 μmol L-1); while the artisans showed highest prevalence
of GID and IDA, though there was no significant difference (p>0.05).
||Influence of educational level of the subjects on the prevalence
of GID and IDA
|*%GID/%IDA: Urban (p = 0.409/0.314), rural (p = 0.111/0.143)-Pearsons
χ2 used, Values with superscript § and £ showed
statistical significance at p<0.01 and p<0.05, respectively-ANOVA
||Influence of living accommodation on the prevalence of GID
|*%GID/%IDA: Urban (p = 0.905/0.179), Rural (p = 0.564/0.034)-Pearsons
In the Table 7, the urban women who never acquired any formal education showed significantly (p<0.01) higher mean serum Fe level (23.0"14.9 μmol L-1), while those with tertiary education showed higher prevalence of GID (67.6%), which was insignificant (p>0.05). In rural counterpart, the women with no formal education showed significantly (p<0.05) higher mean serum Fe level (22.5"24.9 μmol L-1) and insignificantly lower prevalence of GID (38.1%). Similarly, lower prevalence of IDA was detected in the Ano-formal-education@ women of both the urban (33.3%) and the rural (32.6%), though none of the cases proved statistically significant (p>0.05).
In the urban, those living in single room, followed by those in flat, showed lower mean serum Fe level and higher incidence of GID, while prevalence of IDA rather peaked on those living in bungalow (61.5%) (Table 8). Similar relationship applies to the rural sub-groups, where the women residing in single room showed lower mean serum Fe level and higher prevalence of GID than the rest, while the vulnerability to IDA was higher on those residing in bungalow still; but none of the sub-groups was statistically significant in each case (Table 8).
Iron is an important trace element in human nutrition. During pregnancy, insufficient
supplies of iron can lead to a state of biological competition between mother
and the conceptus, culminating to iron deficiency, which can be detrimental
to the health status of both (King, 2003). Anaemia due
to iron deficiency has been noted to be the most prevalent nutritional deficiency
problem affecting pregnant women (Thirukkanesh and Zahara,
Okwu and Ukoha (2008) reported from their study, a
higher prevalence of IDA in the rural than the urban areas of their study. While
Obasi and Nwachukwu (2013) reported higher vulnerability
of the rural women to gestational anaemia than their urban counterparts. In
the present comparative study, the observation is showing a higher prevalence
of GID and the consequent IDA in the urban region than in their rural counterpart.
This is an unlikely expectation; as one would ordinarily expect that urban subjects
should be on a better nutritional placement. The emergence of this phenomenon
might be due to the insufficient micronutrient intake, as a result of a monotonous
and imbalance diet, wherein farinaceous products prevail among the urban settlers.
The above statement could be evident from table 1, where higher
energy level than normal (mean BMI of 27.3"3.94 kg m-2) was recorded
against the urban subgroup. It is speculatively possible to attribute this Aunfamiliar@
finding to a pattern of lifestyle that is always common among the urban settlers.
In the first instance, it is common that most urban settlers always go for refined
synthetic canned foods and beverages in place of the mineral-rich natural ones.
In addition, the unnecessarily carefree Ahigh@ social life of women,
in which good number of them craves red wines in addition to tea and coffee
beverages mostly in the urban area, could be another reason for their relatively
high prevalence of GID and then IDA (which is just an advanced stage of the
former). These are known to contain phenolic compounds believed to exhibit inhibitory
effect on Fe absorption (Kennedy et al., 2003).
As a consequence, iron deficiency becomes imminent, especially during pregnancy.
Such carefree Ahigh@ social life of women is not commonly, if at
all, obtainable among the rural dwellers. Meanwhile, the rural women of our
study area grow dark green leafy vegetables (like fluted pumpkin), as a hobby
at least. And dark green leafy vegetables are natural sources of Fe. They also
keep fruit plantations like pawpaw, mango and guava (natural sources of Vit.
A), as well as orange (a natural source of ascorbic acid) (Devlin,
2006). These vitamins are known to facilitate non-heam iron absorption (Bloem
et al., 1990; Thurnham, 1993; Murray
et al., 2003; Rang et al., 2003). These
might be associated with the better iron status of the rural women, since they
can always eat these natural foods at will. Little wonder therefore, why the
rural women with normal serum Fe level evidently peaks over the GID and IDA
groups; whereas in the urban area, such (i.e., the normal group) was at the
nadir (Fig. 1).
Though the pregnant women were always given nutrients supplements (in tablets,
capsules or lozenges), their full compliance to this supplements is not always
guaranteed. It has been observed that noncompliance to daily nutrients supplementation
by pregnant women is a significant issue seriously militating against their
nutritional status (Galloway et al., 2002). Even
though their study did not show statistical significance, Thirukkanesh
and Zahara (2010) came up with a finding that the percentage of antenatal
women who complied with nutrients supplementation was lower in the urban than
in their rural counterparts; and that those who complied had normal [Hb] compared
to the noncompliant group. This might not be dissociated from the higher prevalence
of GID and IDA among our study urban subgroup, whose greater number was civil
servants (Table 6). The women of this caliber could engage
in Awhite collar@ jobs, where they would often, spend long hours
in the office works at the cost of keeping to their nutrients supplements regimen.
Early antenatal registration is a necessary practice for possible healthy pregnancy.
The absence of women in their 1st trimester among the urban subgroup (Table
3) is an indication of laxity toward such necessary practice. Again, this
could be a contributory factor to the poorer Fe status of the urban subjects
than their rural counterparts.
Besides, it was discovered during the course of the study that the rural women
were served with powdered soymilk (ground soybeans) in addition to the orthodox
nutrients supplements. Soybean is known to be rich in micronutrients including
non-haem iron and vit. A, to mention but a few (Burks et
al., 1991). This could be another good reason for better gestational
iron status of rural subjects than their urban counterparts.
This study shows no significant effect of obstetrics and economic factors on
the Fe status of the pregnant women in any of the regions. This does not conform
to earlier studies of Ugwuja et al. (2010) and
that of Obasi et al. (2013), who rather reported
them as predisposing risk factors.
It could be concluded from this study therefore, that GID and the consequent
IDA were significantly more prevalent in the urban than in the rural regions
of our study. Obstetrics and economic factors were not seen as the significant
We wish to appreciate the management of our target hospitals (FETHA and SVHN) for giving their approval. Our thanks also go to our valued subjects (the pregnant women) for their voluntary consents and supports. We extend our immense gratitude to the health workers of the two hospitals for their unalloyed assistance. In a special way, we acknowledge the contributions of Mr.T.F. Emmanuel in the laboratory analysis of the samples (for iron levels).