Background: Normal and abnormal development of anorectum is still under debate. Etiology of abnormal development of anorectum is poorly understood. Caffeine is a vasoconstrictor that has been implicated in abnormal anorectal development and is a major constituent of Kola nut (Cola nitida). It is consumed heavily by pregnant women in Nigeria to control vomiting. 

Objectives: We examined the teratogenic effects of oral administration of aqueous extract of Cola nitida (AECON) on foetal growth and development of distal gastrointestinal tract in wistar rats. 

Methods: Twelve pregnant Wistar rats used for this study were divided into the Control group that received distilled water and experimental groups E1, E2 and E3 that received 200mg/kg, 400mg/kg, 600mg/kg of AECON respectively orally throughout the period of pregnancy. Gross and microscopic examinations of the pups recovered were conducted to observe the various external and internal congenital malformations in the different groups. Recorded data were analyzed using one-way ANOVA followed by Dunnette test. Values were considered statistically significant at p<0.05. 

Results: There was a progressive reduction in the number of litters with increasing dosage of AECON in the experimental groups. Also, the weight of the pups in the experimental groups were reduced in comparison with the control group. None of the pups in all the groups had anorectal malformations or other associated congenital anomalies.Histopathological and biochemical changes were evident following administration of the extract.

Conclusion: Oral administration of AECON during pregnancy does not have teratogenic effect on the rats but has adverse effects on foetal development and also affected biomarkers of liver damage.