научный журнал «Актуальные исследования» #45 (72), ноябрь '21

Changes in hematology parameters in the first trimester pregnant women

During pregnancy, hematological changes are considered as one of the important factors affecting the health of both mother and fetus. Objective: to describe changes in complete blood count and coagulation in the first trimester of pregnant women. Subjects and methods: a cross sectional study involving 261 healthy pregnant women with gestational age 9-12 weeks who were checked at Hanoi Obstetrics and Gynecology Hospital and 32 healthy nonpregnant women. The indices in this study includes: RBC, Hb, Hct, MCV, MCH, MCHC, WBC, PLT, PT, aPTT, fibrinogen.

Аннотация статьи
pregnant women
CBC. complete blood count
Ключевые слова


During pregnancy, a woman will experience important changes in peripheral blood composition such as red blood cell count, hemoglobin concentration gradually decreases in the second half of pregnancy, and anemia occurs mainly during this period [1]. Slight decrease in platelet count and concentration [2]. Total white blood cell count increased, mainly neutrophils increased [3]. Coagulation system became hypercoagulation [4]. However, these changes were not reported so clearly. Therefore, we conducted this study with the following objectives: Describe the changes in complete blood count and coagulation in first trimester pregnant women.


The study was carried out at Hanoi Obstetrics and Gynecology Hospital and Bach Mai Hospital in 2013. The research group included 261 pregnant women 18-40 years old, gestational age 9-12 weeks, consented to participate in the study. The control group consisted of 32 normal, healthy women of childbearing age who were not pregnant.

Methods: prospective, cross-sectional, controlled study. Each subject was taken blood once for testing complete blood count and coagulation at 9-12 weeks of pregnancy.

The research indices included: red blood cell count (RBC), Hemoglobin (Hb), Hematocrit (Hct), mean red blood cell volume (MCV), mean erythrocyte hemoglobin concentration (MCHC), mean red blood cell hemoglobin concentration (MCH), White blood cell count (WBC), Platelet Count (SLTC),

Data analyse: Data was managed and analyzed on SPSS 20 software.


The average age of study group was 26.19± 5.31 years old, the control group was 25.56 ± 5.07 years old. The difference was not statistically significant (p>0.05).

Table 1

Complete blood count in study group



Study group

Control group


RBC (T/l)

4.36 ± 0.29

4.34 ± 0.2


Hct (l/l)

0.38 ± 0.03

0.4 ± 0.03


Hb (g/l)

126.03± 10.06

128.09 ±7.28


MCV (fl)

86.22± 6.49

85.16 ± 6.23


MCH (pg)

28.99± 2.36



MCHC (g/l)

336.16± 8.33

341.68 ±8.05



9.35± 1.98



PLT (G/l)




Table 1 showed that the HCT, MCHC, WBC, and PLT indexes in these two groups were statistically significant. Anemia, leukocytosis and thrombocytopenia were common trends in pregnancy [5, 6]. Our data showed that some indicators of red blood cell line start to decrease, white blood cell and platelet count increases slightly. There were some theories that suggest that this phenomenon is due to the body's response to the stress of pregnancy [3].

Table 2

Coagulation parameters in study group



Study group

Control group






Fibrinogen (g/L)




PT (s)












APTT (s)








Table 2 showed that, with the exception of PT and INR, the mean coagulation parameters changed significantly: fibrinogen was higher, APTT was shorter and the platelet count was lower than the control group.

Thrombocytopenia was a common sign in 6-10% of pregnant women, gestational thrombocytopenia can be caused by many reasons, of which the main cause is increased platelet consumption accounting for 75-80% of pregnancy thrombocytopenia cases [7].

Liu XH, Jiang YM, Shi H, Yue XA studied on platelet of 232 pregnant women, their result showed that in the first trimester pregnancy, the mean value of platelet count was 158G/L (ranged from 87-238 G/L) [8], which is lower than ours, perhaps due to differences in study design.

Shortened activated partial thromboplastin (APTT) reflects increased activation of the endogenous coagulation pathway. The shortening APTT index indicated the increased activation of coagulation by endogenous pathway. It is worth noting that the mean PT was not statistically different from the control group, so is the exogenous coagulation pathway slower to respond to pregnancy than the endogenous pathway?

Plasma fibrinogen concentration is an important factor in coagulation and hemostasis. During the initial hemostasis phase, plasma fibrinogen concentrations are required for platelet adhesion and aggregation. The reactions in the coagulation cascade all lead to the ultimate goal of converting the plasma fibrinogen concentration to fibrin to form a stable hemostatic plug. Elevated plasma fibrinogen concentrations are evidence of inflammation, vascular injury, and these lesions enhance platelet activation, endogenous and exogenous coagulation pathways. The results in Table 2 showed that the mean plasma fibrinogen concentration in pregnant women was significantly increased compared to the control group (p<0.001), showing that there was a response of this index to the pregnant state from the beginning of pregnancy. Thus, it can be seen that in the first-line coagulation tests, plasma fibrinogen concentration is an indicator of early change. One of the causes leading to this phenomenon is probably the formation and development of the placenta which caused vascular damage and activation of the coagulation pathway [9].


Decreased HCT and MCHC, increased SLBC, decreased SLTC, shortened aPTT, increased fibrinogen compared with the control group were the hematological changes which were reported in first trimester pregnant women. These indicators represent the pregnant women's response to pregnancy and should be monitored in future pregnancies.

Текст статьи
  1. Surabhi Chandra, Anil Kumar, TriSanjay Mishraet al (2012). Physiological changes in hematological parameters during pregnancy. Indian Journal of Hematology and Blood Transfusion, 28(3), 144-146.
  2. Gauer R.L., Braun M. (2012). Thrombocytopenia. American family physician. Am Fam Physician, 85(6), 612-622.
  3. Cunningham F., Leveno K., Bloom S. et al (2010). Maternal physiology. Williams obstetrics, 23, 108.
  4. Niraj Yanamandra, Edwin Chandraharan (2012), Anatomical and physiological changes in pregnancy and their implications in clinical practice. Obstetric and Intrapartum Emergencies: A Practical Guide to Management, Cambridge University Press.
  5. Curtis G.B., Schuler J. (2011). Your Pregnancy Week by week (7th Revised, Updated ed.), Hachette Books, Da Capo Lifelong, Philadelphia, PA, United States.
  6. Lurie S., Rahamim E., Piper I. et al (2008). Total and differential leukocyte counts percentiles in normal pregnancy. European Journal of Obstetrics & Gynecology and Reproductive Biology, 136(1), 16-19.
  7. Burrows R.F., Kelton J.G. (1993), Fetal thrombocytopenia and its relation to maternal thrombocytopenia. N Engl J Med 329(1463), p6.
  8. Liu X.H., Jiang Y.M., Shi H. et al (2009), Prospective, sequential, longitudinal study of coagulation changes during pregnancy in Chinese women, Gynaecol Obstet, 105(3), 240-243.
  9. Lanir N, Aharon A, Brenner B (2003), Procoagulant and anticoagulant mechanisms in human placenta. Semin Thromb Hemost, 29(2), 175-184.
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