Structural Alterations in the Placenta of Wistar Rats Following Administration of a Common Nigerian Herbal Preparation During Pregnancy

The use of herbal preparations during pregnancy is prevalent across all geopolitical zones of Nigeria, driven by cultural practice and limited access to antenatal services. Many of these preparations have not been evaluated for their effects on placental structure and function, raising concerns about placenta-mediated foetal developmental effects. This study aims to evaluate placental structural alterations in pregnant Wistar rats administered a standardised aqueous extract of a commonly used Nigerian herbal mixture at clinically estimated doses during the second and third trimesters. Forty pregnant Wistar rats will be randomised into control, low-dose, medium-dose, and high-dose extract groups. At term, placentas will be harvested and processed for light microscopy. Haematoxylin and eosin sections will be examined for labyrinthine zone thickness, junctional zone integrity, decidual cell morphology, and trophoblast layer architecture. Placental weight and morphometry will be recorded. Foetal weight and crown-rump length will be measured as proxies of placental function. The study anticipates providing experimental anatomical evidence on the potential placentotoxic effects of this herbal preparation and supporting evidence-based counselling of pregnant women regarding herbal use during antenatal care in Nigeria.

Keywords: placental histology, herbal preparation, pregnancy, Wistar rats, placentotoxicity