Morphology and morphometric analysis of stromal capillaries in full term human placental villi of smoking mothers: an electron microscopic study.

Objectives: The capillaries of placental villi play a very important role in the feto-maternal exchange of gases and nutrients. A morphological change in their structure may lead to the impairment of placental function. In this study an attempt has been made to find out the morphological and morphometric features of the capillaries in full term placental villi of non smoking mothers as well as active and passive smoking mothers under an electron microscope.

Materials And Methods: A total number of 163 placentae from active, passive and nonsmoking mother (n = 61+42+60) were processed for electron microscopic study. The ultrathin sections were examined under electron microscope and images were recorded. Morphometry and statistical analysis were carried out with the help of software.

Results: The study revealed that the endothelial cells of stromal capillaries of the placental villi were oedematous and the cytoplasm was rich in dilated endoplasmic reticulum, mitochondria, fibrils and fine filaments in both groups of the smokers' placenta in comparison to control. Morphometric analysis showed a significant reduction in the perimeter of the stromal capillary of the tertiary villi of placenta in both active and passive smokers from mean value of 71.65 ± 47.82 µ to mean value of 59.77 ± 29.72 µ (p = 0.07) and 49.49 ± 20.94 µ (p = 0.0005) respectively. In case of passive smoker, area of the capillary (µm²) reduced significantly (p = 0.00004) from mean value of 266.29 ± 331.86 µm² to 116.64 ± 83.62 µm² whereas the number of capillary per villus increased significantly (p = 0.046) from mean value 2.42 ± 1.84 to 4.2 ± 3.16. The thickness of basement membrane of the endothelial cells of stromal capillaries of the placenta increased significantly in active as well as passive smokers (p = 0.00001).

Conclusions: The ultrastructural changes noticed in the endothelial cells of placental villi may be due to hypoxia resulting from tobacco consumption either in active or passive form by the pregnant mothers. Thus, targeted therapy may be implicated for hypoxia, which is one of the major cause of the life threatening disorders of pregnancy.