Just enquiring! not going to take it without advice from health professional.

I’ve heard castor oil can cause labour to start and that ISN’T what I want. However I am severely constipated at 35 weeks and castor oil is something that has come up as a suggestion within my searches for methods to help , I’ve tried everything else and thinking this is the last resort, if there is a way I can take it without causing premature labour? Advice please , is it possible to take it without causing labour