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April 1992, Volume 42, Issue 4

Original Article


Saadiya Aziz Karim  ( Departments of Obstetrics and Gynaecology, Aga Khan University Hospital, Karachi. )
Muhammad Khurshid  ( Departments of Pathology, Aga Khan University Hospital, Karachi. )
Javaid H. Rizvi  ( Departments of Obstetrics and Gynaecology, Aga Khan University Hospital, Karachi. )
Sadiqua N. Jafarey  ( Department of Obstetrics and Gynaecology, Jinnah Postgraduate Medical Centre, Karachi. )
Iffat Rizwana  ( Departments of Obstetrics and Gynaecology, Aga Khan University Hospital, Karachi. )


A study involving the obstetric clinic population of 3 major teaching hospitals of Karachi has been conducted to define changes in leucocyte and platelet counts as pregnancy progresses. 573 “normal” pregnant women - 183 in the first trimester, 195 in the second trimester and 194 in the third trimester were included in this analysis. We have found leucocytosis to be a feature of normal pregnancy; the change is subsequent to a progressive increase in granulocytes. Platelet counts were found to decrease slightly as pregnancy progresses (JPMA 42: 86, 1992).


Studies on leucocyte counts in pregnancy have suggested a ‘physiological’ leucocytosis confined to neutrophils1. The neutrophil count rises as early as the estrogen peak of a normal menstrual cycle and if fertilization occurs, neutrophuls continue to rise2. A maximum is reached on the 15th post ovulation day followed by a fall3. There is a subsequent rise to a peak at 30 weeks4 and plateau during the third trimester. Analysis of platelet counts in pregnancy record a statistically significant fall as pregnancy progresses5-7. This has been re- emphasized by Fay et al8 who also suggest an increased platelet destruction throughout normal pregnancy. Lack of data on the haematological status in pregnant Pakistani women has prompted this study. The aim is to define a range of normal and mean values for leucocyte and platelet counts in the three trimester of pregnancy.


Normal pregnant women attending the antenatal clinics of three major teaching” hospitals of Karachi. The Aga Khan University Hospital, between November 1986 and October 1987 and between January 1990 and July 1991, the Civil Hospital, between May 1987 and October 1987 and the Jinnah Postgraduate Medical Centre be­tween January1988 and June 1988, were included in this analysis. Excluded were anaemic women (Hb < 10 gm/dl), those suffering from infections or diseased states and those on drugs known to alter platelet or white cell Counts. Also excluded were women with hypertension, diabetes and other medical problems. Consecutive women seen at the above hospitals at their 1st (booking visit) were included until a total of about 200 in each trimester were reached. The study population comprised women of all socio-economic levels, ages 16 to 45 and all parities (primiparae to 12th gravidae). Trimester 1 was defined as 6 to 13 weeks pregnancy, trimester 2, 13 + to 26 weeks pregnancy and trimester 3,26 + weeks to term. Total differential leucocyte counts and platelet counts were measured by the Coulter S + 4 automated haematology analyser at The Aga Khan University laboratory. A standard test of significance (Z test) was applied.


The results of our study are shown in Table I and II.

The number of patients studied were 183 in trimester 1, 195 in trimester 2 and 194 in trimester 3. Of the 183 women in the first trimester, 71 (38.8%) had leucocytosis (total count> 10,000). This increased to 49.2% in second trimester and 52.1% in third trimester. The mean total white cell count was 9.7 in the 1st trimester (range 5.0 to 16) increasing to 10.1 in the 2nd trimester (range 5.4 to 16.6) and 10.4 in the 3rd trimester (range 4.4 to 18). The mean granulocyte count rose from 6.0 in the 1st trimester to 6.6 in the 3rd trimester and the change is statistically significant (Z test, P.0.005). The mean lym­phocyte count remained fairly constant throughout pregnancy with values similar to those in the non-preg­nant. There was a wide range in platelet counts in all three trimesters of pregnancy. Mean values were similar (278 in trimester 1, 275 in trimester 2, 266 in trimester 3) with a drop in average platelet count in the third trimester compared with the first trimester.


Leucocytosis is mentioned as a common feature of pregnancy in reviews by both obstetricians and haematologists9,10. We have found it to be present amongst 38.8% normal pregnant women in early preg­nancy increasing to 52.1% in the third trimester. It is therefore likely to be a normal feature of pregnancy. Mean total leucocyte counts are high normal (9.7 to 10.4) at all stages of pregnancy. The rise in total white cells is due to progressive increase of granulocyte from early to late pregnancy whereas the mean lymphocyte count remains static at the non-pregnant level. This is in accord with prior work4. Platelet counts have been shown to decrease slightly but significantly during pregnancy11. This change was explained by either haemodilution or hyperdestruc­tion8. We have found the platelet count to be normal at all stages of pregnancy with a slight fall in average counts as pregnancy progresses. These findings in a Pakistani population confirm those of prior studies in the West4,11.


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7. Pitkin, R.M.] and Witte, DL Platelet and leucocyte counts in pregnancy. JAMA., 1979, 222696.
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9. Letsky, & The hacmatological system, in clinical physiology in obstetrics. Edited by Frank Hyuen and Geoffrey Chamberlain. Oxford, Blackwell, 1980, pp.43-60.
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11. Hytten, F.E., and Leitch, I.The volume and composition of the blood, in the physiology of human pregnancy. 2nd ed. Oxford, Blackwell, 1971, pp. 1-10.

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