It is generally not recommended to apply castor oil on the belly during pregnancy, especially without consulting with a healthcare professional. While some people believe that applying castor oil can help induce labor or promote bowel movements, there is limited scientific evidence to support these claims. In fact, using castor oil as a laxative during pregnancy can lead to dehydration and electrolyte imbalances, which can be harmful to both the mother and baby. Additionally, applying castor oil topically may cause skin irritation or allergic reactions. It is always best to consult with your healthcare provider before trying any new remedies or treatments during pregnancy. They can provide personalized advice based on your specific situation and medical history.