Histological Evaluation of Placentas in Idiopathic Intrauterine Growth Restriction.

Background Idiopathic intrauterine growth restriction (IUGR) is a condition in which there is no discernible cause, such as problems with the mother's health, and the fetus does not grow to the expected size for its gestational age. In cases of IUGR, the placental trophoblast exhibits reduced invasiveness, leading to a less extensive invasion of uterine spiral arteries and increased resistance in the uteroplacental circulation. The consequences of these early histopathological alterations are long-lasting, resulting in compromised blood flow to the placenta and diminished transport of nutrients and oxygen from the mother to the fetus. The placentas of neonates with idiopathic IUGR may provide crucial insights into the underlying causes of this growth restriction. The present study was designed to evaluate various microscopical changes in placentas of idiopathic intrauterine growth-restricted cases, qualitatively and quantitatively. Methods After getting the ethics committee's approval, the placental samples were collected from Duhok Obstetrics and Gynecology Hospital, Duhok, Iraq. A total of 55 placentas were gathered from women aged 20-40 years who had full-term (37-40 weeks) singleton pregnancies. Control cases were selected randomly, while idiopathic IUGR cases were selected purposively. Out of 55, 35 placentas were taken from idiopathic IUGR (birth weight less than 2500 g), and 20 placentas were taken from normal pregnancies (control group) with no history of confounding maternal and fetal factors. The maternal and neonatal data (age, weight of neonate, gestational period, and gender of neonate) were recorded. Immediately after delivery of the baby, the placenta was taken, washed with tap water, and dried. Then central and peripheral biopsies were taken for qualitative and quantitative histopathological examination, which includes the following: the number of terminal villi, stromal fibrosis, fibrinoid necrosis, syncytial knots, hyalinization, chorangiosis, congestion, and calcification. Statistical analyses were done using Student's t-tests and chi-square tests. Results In the idiopathic IUGR group, the qualitative features of the microscopic study corresponded with quantitative measurements. There was a significant decrease in the mean number of terminal villi (p=0.02), a highly significant increase in syncytial knots (p=0.001), a highly significant increase in fibrinoid necrosis (p=0.003), a highly significant increase in the mean number of stromal fibrosis (p=0.001), and a significant decrease in hyalinization (p=0.05). There was an insignificant increase in the calcification, medial coat proliferation of medium-sized blood vessels, chorangiosis, congestion, and fatty degeneration. Conclusions The reduction of terminal villi, accompanied by an increase in syncytial knots, fibrinoid necrosis, and stromal fibrosis, may have reduced the surface area for fetomaternal exchange. This led to chronic placental insufficiency. As a result, fetal growth and development are restricted. Therefore, IUGR infants may need more scientific and clinical attention.