Excessive consumption of red meat is harmful to our health (cardio-vascular disease, cancer, diabetes) and to the environment. However, its effects on pregnancy are still poorly understood. The aim of this literature review was to examine the effects of a diet rich in red meat or, on the contrary, a vegetarian diet, on the course of pregnancy and fetal development. A correlation was found between a high intake of red meat and the risk of developing gestational diabetes, while a vegetarian diet, although associated with a risk of vitamin B12 and iron deficiency, does not appear to pose a risk if it is well balanced. However, current data on this subject is insufficient and should be further developed, especially in the context of the climate crisis.