Evaluation of Serum Proteins in Pregnancy

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Jemikalajah J.D.
Department Of Medical Microbiology And Parasitology, Faculty of Clinical Science, Delta State University, Abraka.
Adu M.E.
Department Of Medical Laboratory Services, Antiretroviral Therapy Centre, Central Hospital, Agbor.

All Corresponding to: adumatthew10@yahoo.com

ABSTRACT

Pregnancy induced changes in the maternal system in order to accommodate the foetus. One of such changes is the anabolism and catabolism of plasma proteins. The effects of pregnancy on serum proteins were investigated in eighty (80) pregnant women attending antenatal clinic in central hospital, Auchi and forty (40) apparently healthy women as controls. Total protein, albumin, and globulin as well as albumin/globulin ratio were examined. There was decreased total protein, albumin and albumin/globulin ratio and increased globulin in pregnant women when compared with non- pregnant women. Also there was significant difference when different trimesters were compared. These changes are attributed to increased plasma volume as well as synthesis of pregnancy induced plasma proteins. We advocate the routine examination of serum protein during pregnancy.

Keywords: Serum proteins, Pregnancy, Globulin, Auchi, Trimester

INTRODUCTION

Pregnancy involves the sequence of events that take place after fertilization of an ovum, thus enabling the fertilized ovum to eventually develop into a full- term foetus (Guyton and Hall, 2000). During pregnancy estrogen and progesterone are produced in large quantities and exert some influence on a pregnant woman. These hormones induce an increase in the metabolism of the woman as she prepares to carry the baby (Bassi et al., 2011). Physiological response in the metabolism of the expectant mother is due to foetal requirement of oxygen and food substance, growth of the uterus and preparation for lactation. The pregnant women experience physiological changes to support fetal growth and development (Blackburn and Loper, 1992, Taylor 1995). The level of estrogens (estradiol) and progesterone increase progressively during pregnancy (Vanthiel and Gavaler, 1987). These sex hormones have effects on hepatic metabolic, synthesis, and excretory functions (Vigil and Gratia, 2004, Bacq, 1999, Marpeau et al., 1999). The phenomenon of hemodilution secondary to the increase in plasma volume decreases the serum protein concentrations. Consequently, certain changes in values of liver function tests occur during normal pregnancy (Everson 1998, Alonso 2006). There are scanty literatures on the serum proteins of pregnant women especially in the locality studied; we therefore sought to determine the serum proteins of pregnant women in Auchi, Edo State, Nigeria.
MATERIALS AND METHODS
Study Area
This study was carried out in Central Hospital, Auchi, Edo State Nigeria. It is a secondary health institution that serves as a referral centre for other primary health institution in this locality.
Sample Collection
A total of 120 samples were collected from 80 pregnant women attending ante-natal clinic and 40 non pregnant women as controls after informed consent. Five milliliters of venous blood was collected aseptically into a plain container and allowed to clot. This was spun at 3000rpm for 10minutes to obtain a clear serum which is kept frozen until required for analysis. Ethical approval was obtained from the ethics committee of Central Hospital, Auchi.
Biochemical Analysis
Total serum protein was determined spectropho-tometrically using Biuret method (Doumas et al., 1981) while serum albumin was determined by bromocresol green method (Doumas et al., 1981). Serum globulin was calculated by subtracting albumin from total protein. The Albumin Globulin ratio was also determined by dividing Albumin with Globulin. All reagents were products of Randox Laboratories UK. In all test, manufacturer instructions were strictly adhered to.
Statistical Analysis
The groups mean ± SD was calculated for each analyte and significant difference between means evaluated

using the student t-test. Statistical Package for Social Science SPSS version 16.0 software (SPSS Inc., Chicago, IL USA) for windows was used, with P<0.05 considered as statistically significant.

RESULTS
The mean serum total protein of pregnant women was observed to be decrease (6.23±0.69) than the control subjects (6.63±0.43). Mean serum albumin level of pregnant women was found to be 3.43±0.61as against controls which is 3.93±0.36.Table 1 also show the globulin level of both pregnant women and controls to be 2.75±0.29 and 2.70±0.24 respectively. There was decreased Albumin: Globulin ratio observed in pregnant women (1.27±0.29) when compared with control subjects (1.46±1.50).
A/G = Albumin: Globulin Ratio
Fig 1 shows the mean serum proteins of different trimesters with first trimester having an increased total protein when compared with both second and third trimester. There is an increased serum albumin: globulin ratio observed in the third trimester when compared
with first and second trimester.

DISCUSSION
Pregnancy is a period between conception and delivery and has been associated with increased dietary protein requirements in humans. During this period of rapid growth, the foetus and placenta accrue proteins very rapidly (Lewis et al., 2010). Pregnancy induces major physiological, hormonal and biochemical changes to achieve an optimal outcome for the baby and its mother. Our study show significant decreased in total protein of pregnant women when compared with controls. This decrease can be attributed to changes in plasma volume as opined by Varley et al., (1980). The fall in protein concentration seen during pregnancy may be due to the dilution of the plasma, since total protein concentration is inversely related to plasma water concentration (Paaby 1960).

The albumin level of pregnant women was found to be significantly decreased when compared with non-pregnant women. This is in accordance with the findings of Coryell et al., (1950) and Horme et at., (1970) who attributed the decrease in albumin to increased plasma volume found in pregnancy. However, Laurell et al., (1968) stated that albumin synthesis which is normally stimulated due to hypoalbuminemia is inhibited during pregnancy by progesterone and estrogen which is abundant in pregnant women.

There was no significant difference observed in the globulin levels of pregnant and non pregnant women. This is in consonance with the findings of Adedeji et al., (2012) who observed that concentration of serum globulin is not affected by pregnancy. The Albumin/Globulin ratio of pregnant women was significantly decreased when compared with non pregnant women. This similar observation was reported by Adedeji et al., (2012). This difference is attributed to the decreased albumin as occasioned by increased plasma volume.
Our results revealed that the mean concentrations of serum proteins exhibited some variations with advancing gestational age. There was significant increased observed in the total protein of first trimester when compared with second and third trimester. Also there was significant increase in the total protein of second trimester when compared with third trimester. This is in tandem with Adedeji et al., (2012) who did similar work on protein profile of pregnancy. Shimokawa and his colleagueset al et al.,(1980) demonstrated that certain serum protein fraction of molecular weight of 185,000 Dalton are elevated in relative concentration during the first trimester and decrease to non- pregnant levels after 25th week of gestation. There was no significant difference observed between the first trimester and second trimester in albumin level when compared but there exist a significant difference when both first and second trimester where compared with third trimester. This is in agreement with previous findings of Adedeji et al., (2012).This difference is attributed to increased plasma volume being experienced in the third trimester as well as nutritional needs of the foetus. The globulin fraction of first trimester and second trimester was observed not to be significantly different but an increased significant difference was observed when third trimester was compared with both first and second trimester. This difference may be due to the synthesis of various pregnancy induced proteins such as ?- fetoprotein, placental isoenzyme of alkaline phosphatase, oxytocinase, human chorionic gonadotropin and the pregnancy associated plasma proteins. The concentrations of these proteins rise during gestation and disappear within few days or weeks of postpartum as opined by Joseph et al., (1978). The albumin: globulin ratio of the third trimester was significantly increased when compared with both first and second trimester whereas there was no significant difference observed between first and second trimester in the albumin: globulin ratio. This may be probably due to imbalance between albumin and globulin concentration which has been earlier attributed to increased plasma volume and synthesis of pregnancy induced plasma proteins.

In conclusion, alteration in function of any sites will affect the appropriate serum protein fractions. Changes in serum protein during normal pregnancy can also be attributed to varying factors like increase in plasma volume and wide individual physiological variations at any given stage of pregnancy. However, a considerable amount of albumin passes through the glomerular filtrate daily during pregnancy and most of this is reabsorbed in the renal tubules, being broken down in the process and are lost to the body. It is therefore imperative to have a protein profile analysis during pregnancy.
Conflict of Interest: None

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