This review aims to sum up the current knowledge about biological factors of pregnancy related anxiety (PrA) and the most common consequences for both mother and child, thereby identifying the most crucial concerns and suggesting the course of further research in this field. We pursued a literature review using PubMed. Scientists have shown a significant connection between prenatal anxiety and hormonal changes. These alterations include HPA-axis regulation, thyroid function, oxytocin, prolactin, and progesterone levels. PrA is proven to be a multifactorial condition. Several psychological factors correlate with it, e.g., insufficient social support, unplanned pregnancy, lack of physical activity, and a high level of distress. Although pregnancy is a significant change in one’s life and may be a stressful event, it seems inadequate to believe that clinically relevant prenatal anxiety should be explained only by these psychological factors. Pregnancy-related anxiety is a common mental health disorder in pregnancy, and further studies are needed to minimize the risk of its severe consequences.