Histomorphometry of Preterm and Term Human Placentas Histomorfometría de Placentas de Pretérmino y Término

The intra-uterine existence of foetus is dependent on placenta, a major organ of nutrition and homeostasis.The present study was carried out to compare morphometric and histological changes in preterm and term human placentas. Eighty placentas collected from Department of Obstetrics and Gynecology, JNMCH, AMU, Aligarh, were divided into group first of preterm placentas up to 36 weeks (n =30) and second group of full term placentas i.e. 37 to 40 weeks ( n = 50) respectively. The samples were fixed in 10% formol-saline solution. The gross morphological variables of placentas were studied. There was a significant increase in the placental weight, decidual area and umbilical cord diameter of term placenta as compared to that of the preterm ones. From each placenta whole thickness tissue blocks were taken and processed for paraffin sectioning. Five μ-thick sections were stained with Haematoxylin-eosin and Van Gieson stains and processed for light microscopy. A total of 200 villi were studied in each sample under high power field and occurrence of different features was expressed as percentages for each parameter. The appearance of microvilli and syncytial bud on the syncytium were almost absent in the villi of term placentas. It was concluded that with increasing gestational age there was a gradual increase in the number of capillaries in villi from preterm to term placenta.There was a significant increase in syncytial knot count, fibrinoid necrosis, vasculosyncytial membrane and decrease in the percentage of villi showing cytotrophoblastic cells and number of Hofbauer cells in term group as compared to preterm group.