Growth of foetal thymus - A study of it’s morphogenesis in human

J K Sarkar^1*, T Sinha², B C Dutta³

^1,2Associate Professor, ³Professor, Department of Anatomy, Silchar Medical College, P.O. Ghungoor, Silchar-14, Cachar, Assam, INDIA.

Email: jksarkar31@gmail.com, dr.turlikasinha@rediffmail.com, drbijondutta@gmail.com

Abstract               Aims and Objectives: Aim of the study was to find out the appearance, location, size and weight of the thymus in different age group of human foetus. Our objective was to correlate growth of foetal thymus with gestational age, body weight and crown rump length. Materials and Methods: The study was carried out on 90 human foetuses (48 male and 42 female) ranging from 9-38 weeks of gestation following spontaneous loss, elective termination and stillborn without congenital anomalies. The collected fetuses were examined for their Crown rump length and body weight. Then thymus were taken out by dissection of the foetuses. The gland so obtained were examined and weight measured. Results and Observations: Mean weight of thymus and foetus were calculated with standard deviations. The weight of the thymus increased steadily from 9-20 weeks. Thereafter growth rate was more up to 38 weeks of gestation. Therefore, growth rate of thymus with respect to gestational age and body weight of foetuses was nonlinear and relative weight of thymus increased more steeply than the foetal weight. The statistical analysis was done by (ANOVA) GraphPad InStat Software that revealed Pearson’s Correlation coefficient (r) = 0.94, 95% confidence interval: 0.85 to 0.98 and Coefficient of determination (r squared) = 0.89. As the r value is closer to +1, the correlation between weights of thymus with respect to gestational age is significant. All the findings of this present study were then compared with findings of different researchers and their literature. Conclusion: The relationship of the growth of thymus to gestational age is nonlinear. There was no significant sex difference between male and female foetus in regards to their morphology of the thymus.

Key Words: Thymus, morphology, foetus and gestation.