|Year : 2016 | Volume
| Issue : 4 | Page : 194-198
Haematological variables of healthy pregnant women in Sokoto, North-western Nigeria
Abubakar U Musa FMCPath 1, Muhammad A Ndakotsu1, Abubakar A Panti2, Constance E Shehu2, Aminu U Kaoje3
1 Department of Hematology, UDUTH, Sokoto, Nigeria
2 Department of Obstetrics and Gynaecology, UDUTH, Sokoto, Nigeria
3 Department of Community Medicine, UDUTH, Sokoto, Nigeria
|Date of Web Publication||11-Jul-2017|
Abubakar U Musa
Department of Haematology and Blood Transfusion, UDUTH, Sokoto
Context: Pregnancy exerts changes on the haematological system with consequences on interpretation of laboratory results and subsequent diagnosis or intervention. Furthermore, significant variations in haematological variables are known to occur between populations reflecting interplay between genetics and environment.
Aim: To determine the values of haematological variables for normal pregnancy in Sokoto.
Settings and Design: A descriptive cross-sectional study conducted over a 6-week period at antenatal clinics of Usmanu Danfodiyo University Teaching Hospital (UDUTH), Sokoto, North-western Nigeria.
Subjects and Methods: Apparently healthy pregnant women who presented at the antenatal clinics of UDUTH, Sokoto for booking were recruited and had automated full blood count conducted on their blood sample.
Statistical Analysis Used: Data were entered into Statistical Package for Social Sciences software version 17 for descriptive analysis while analysis of variance was employed to compare haematological variables among the trimesters of pregnancy. Level of statistical significance was set at P < 0.05.
Results: A total of 404 pregnant women were recruited and had mean haematocrit, white blood cell (WBC) counts and platelet counts of 33.00 ± 3.62%, 7.78 ± 2.21 × 109/l and 242.51 ± 63.18 × 109/l, respectively. No statistically significant differences were found across the three trimesters of pregnancy in respect of haematocrit, WBC counts and platelet counts (P > 0.05).
Conclusion: This study has provided the values for haematological variables during normal pregnancy, which could serve as reference values for Sokoto and possibly other parts of North-western Nigeria.
Keywords: Haematological variables, pregnancy, reference values, sokoto
|How to cite this article:|
Musa AU, Ndakotsu MA, Panti AA, Shehu CE, Kaoje AU. Haematological variables of healthy pregnant women in Sokoto, North-western Nigeria. Sub-Saharan Afr J Med 2016;3:194-8
|How to cite this URL:|
Musa AU, Ndakotsu MA, Panti AA, Shehu CE, Kaoje AU. Haematological variables of healthy pregnant women in Sokoto, North-western Nigeria. Sub-Saharan Afr J Med [serial online] 2016 [cited 2017 Sep 19];3:194-8. Available from: http://www.ssajm.org/text.asp?2016/3/4/194/210207
| Introduction|| |
Normal pregnancy is accompanied by a number of alterations in maternal physiology with resultant changes in haematological variables.,,,, Documented changes include increase in maternal blood and plasma volume by about 40–50% with accompanying red cell mass increase, albeit to a lesser extent, leading to a fall in haematocrit and a consequent dilutional anaemia.,,,, Leucocytosis, mostly due to neutrophilia, is a frequent finding in pregnancy while varying patterns of platelet counts have been observed.,,,, On the other hand, significant variations in haematological variables have been observed between populations such as relative reduction of leucocyte and platelet counts in blacks., These differences reflect variation in general health as well as an interplay between genetics and environment.,,
Undoubtedly, interpretation of laboratory results during pregnancy needs the appreciation of the pregnancy-induced changes as well as genetic and environmental peculiarities of a given population.
Thus, this study was aimed at determining the values of some haematological variables during normal pregnancy in Sokoto, North-western Nigeria.
| Subjects and Methods|| |
This was a descriptive cross-sectional study conducted over a 6-week period (9th April to 15th May 2014) at the antenatal clinics of the Department of Obstetrics and Gynaecology, Usmanu Danfodiyo University Teaching Hospital (UDUTH), Sokoto. Approval was obtained from the Ethics and Research Committee of UDUTH, Sokoto; informed consent from study participants was also obtained.
All apparently healthy pregnant women who presented for booking during the study period were recruited, had their socio-demographic data obtained and 3 ml of free-flowing venous blood aseptically collected into tri-potassium ethylene di-amine tetra-acetic acid (K3-EDTA) containing blood sample bottles. Samples were kept at room temperature until processing within 4 h of collection.
Excluded from the study were hypertensives, diabetics, asthmatics and those with history of sickle cell disease (SCD) or bleeding disorders. Also excluded were women who had febrile illness over the last 2 weeks or on medication that could affect blood cell counts such as antibiotics, anticoagulants or steroids.
Full blood count was done by automation using Erma PCE 210 (Erma Inc., Tokyo, Japan) haematology analyser at the Department of Haematology, Usmanu Danfodiyo University (UDU), Sokoto, and the principle of cell count employed was that of electronic impedance in which changes in electric resistance, between two electrodes and produced by diluent-suspended cells traversing a small aperture were measured and correlated with specific cells sizes and count.
Data were entered into the Statistical Package for the Social Sciences software version 17 (SPSS Inc., Chicago, IL, USA) for descriptive analysis while analysis of variance (ANOVA) was employed to compare haematological variables among the trimesters (based on the traditional 3 months per trimester, i.e. 0–13 weeks, 12–26 weeks and 27–40 weeks for first, second and third trimesters, respectively) of pregnancy. Post-hoc analysis was conducted for significant ANOVA P values. Level of statistical significance was set at P < 0.05.
| Results|| |
A total of 404 pregnant women were recruited for the study with mean ages and gestational ages of 27.50 ± 5.87 years and 22.92 ± 5.82 weeks, respectively. The distribution of study participants according to trimesters of pregnancy were 14 (3.47%), 101 (25.00%) and 289 (71.54%) for first, second and third trimesters, respectively.
The mean haematocrit, white blood cell (WBC) counts and platelet counts across pregnancy were 33.00 ± 3.62%, 7.78 ± 2.21 × 109/l and 242.51 ± 63.18 × 109/l, respectively. The mean corpuscular volume (MCV), the mean corpuscular haemoglobin (MCH) and the mean corpuscular haemoglobin concentration (MCHC) were 81.00 ± 5.28 fl, 25.70 ± 3.81 pg and 31.66 ± 3.49 g/dl, respectively. The mean values for other haematological variables across pregnancy and according to trimesters of pregnancy are as depicted in [Table 1].
|Table 1: Mean values for haematological variables across pregnancy and outcomes of comparison of haematological variables among the trimesters of pregnancy|
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No statistically significant differences were found across the three trimesters of pregnancy in respect of haematocrit, WBC counts and platelet counts (P > 0.05), whereas no statistically significant differences were noted for MCH and MCHC across the trimesters of pregnancy (P > 0.05); the MCV in the second trimester was, however, found to be significantly higher than that of the first trimester (P > 0.024). The results of comparison of haematological variables between the trimesters of pregnancy are also shown in [Table 1].
| Discussion|| |
Normal pregnancy is accompanied by changes in maternal physiology with resultant alterations in haematological variables.,,,, These changes include expansion in maternal blood volume and accompanying red blood cell (RBC) mass increase, albeit to a lesser extent, leading to a fall in haematocrit and consequent dilutional anaemia.,,,,
Our values for the mean haematocrit, haemoglobin, RBC count, MCV, MCH and MCHC were found to be lower than those observed by Isa and colleagues working on apparently healthy non-pregnant women in nearby town of Zaria in North-western Nigeria. Similarly, higher mean values among non-pregnant Nigerian women have been reported earlier by the separate studies of Imoru, Osuagbaka et al. and Umeh and Emelugo in Kano, Port Harcourt and Anambra, respectively. As hinted earlier, these differences are the results of pregnancy-induced changes as well as the accompanying increased nutrients’ demand, which typifies the pregnant state.
A fall in haematocrit, haemoglobin and RBC count from first trimester to the second trimester and a subsequent rise in same variables by the third trimester were observed in our study. The findings of Akingbola et al. and Akinbami et al. concurred with ours in respect of the haematocrit, but in contrast, they recorded a steady fall in both haemoglobin and RBC count from the first trimester through the third trimester. Our observed rise in the MCV from the first trimester to the second trimester and a slight fall of same by the third trimester concur with the findings in normal pregnancy and reported by several other researchers.,,, The MCH and MCHC in this study rose from the first to the second trimester and then dipped during the third trimester, as was the case with the Akinbami et al.’s study; however, this was in contrast to the uninterrupted rise observed by Akingbola et al. Our study and that of Akingbola et al. observed an initial drop with the red cell distribution width (RDW) from the first trimester to the second trimester before a rise during the third trimester while in contrast to this, a sustained increase in RDW during pregnancy was observed by the separate studies of Ifeanyi et al. and Purohit et al. These observed differences could be attributable to the varying responses induced by the dilutional anaemia of pregnancy and that are largely determined by nutritional status, prevalence of infection and genetics.,,
Leucocytosis is a frequent finding in normal pregnancy as reported by numerous researchers and has been attributed to increased inflammatory response, a consequence of selective immune tolerance, immunosuppression and immunomodulation of the fetus.,,,, It is worthy of note that lower WBC counts than those observed in our study have been reported among the healthy non-pregnant Nigerians and this finding further highlights on the effect of pregnancy on blood cell counts.,,,
Our study found, similar to that of James et al., a rise in WBC count from the first trimester to the second trimester, which dipped during the third trimester though not below the level for the first trimester. In contrast, the Akingbola et al. and Akinbami et al. studies found a sustained increase of the WBC count across the three trimesters of pregnancy. The observed leucocytosis is secondary to neutrophilia arising from impaired neutrophilic apoptosis in pregnancy as well as stress-induced redistribution of WBCs between the marginal and circulating pools.,,, While monocytosis has also been reported in normal pregnancy, a decline in the number of the other cells in the differential count was noted., In agreement with the above, our study recorded a gradual increase in granulocyte count but an accompanying steady fall with both lymphocyte and monocyte count as pregnancy advances.
In respect of platelet count, our observed values across pregnancy were found to be lower than those reported by Isa et al. among the healthy non-pregnant women in Zaria. With regard to pregnancy, most studies have reported a gradual decrease in platelet count as normal pregnancy progresses, a finding attributed to dilutional effect and increased consumption of platelets within the utero-placental circulation.,,,, Some studies including that of van Buul et al. have, however, reported an increase in platelet counts in normal pregnancy. Our study observed a fall in platelet count from first trimester to second trimester, but the count rose in the third trimester to about the same level recorded for the first trimester. Both studies by Akingbola et al. and Ifeanyi et al. found an initial rise in platelet count from the first trimester to the second trimester before a subsequent rise by the third trimester.Incidental thrombocytopaenia of pregnancy accounts for about 75% of thrombocytopaenic cases in pregnancy while 21% are secondary to hypertensive disorders and 4% have been associated with immune thrombocytopaenic purpura., Our study found only four (1.0%) women who were in their second trimester to be thrombocytopaenic (platelet count <100 × 109/l) but most had their platelet count within the normal reference range. Akingbola et al. documented a higher incidence of 3.6% for thrombocytopaenia in healthy pregnant women. It is worthy of note that incidental thrombocytopaenia of pregnancy requires no specific treatment and resolves after delivery but being a diagnosis of exclusion, other aetiologies must be excluded.,
| Conclusion|| |
From the foregoing, it could be appreciated that pregnancy, in addition to genetics and environmental factors, exerts some effects on haematological variables. This underscores the need to interpret results of laboratory investigations during pregnancy with caution and in the light of specific population-based reference values.
Our study, conducted on apparently healthy pregnant women, has provided the values for some haematological variables, which could serve as reference values for normal pregnancy in Sokoto and possibly other parts of North-western Nigeria.
Limitation of the study
Inclusion of apparently healthy matched non-pregnant controls would have further highlighted on the effects of pregnancy on blood counts.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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