Absolutely not. Castor oil has a powerful impact on your bowels and entire body, so it's not an option to be used without proper knowledge or need. It should only be used when past forty weeks, and when other less invasive options have not worked. At thirty-four weeks, a baby's lungs and brain have not finished development, and your baby hasn't gained all the weight and functions that develop in the last four weeks of pregnancy. A baby born at thirty-four weeks will end up in special care, and likely have difficulty with feeding, temperature control and be at higher risk of health issues. If you feel that the pregnancy is too painful or uncomfortable, find a medical practitioner or qualified natural health practitioner who can assess the problems and offer ways of dealing with them, without giving birth this early.