I have heard many times that in order for a woman to use a contraceptive pill, a heter is required from a moreh horaah. I understand the need with regard to halachically questionable forms of contraception, but I don’t understand why this is necessary in the instance of using a pill. If someone knows on his own that based on his situation (for example he has already a boy and a girl and more than one or two of each) that it would be difficult to have another child, why can’t the decision be made without a rav?
Thank you for your question.
Even if a person has a boy and a girl, there is still the concept of לערב אל תנח ידיך, meaning that a person should continue having children as long as they can. If they feel that doing so will be detrimental to either themselves or their children, they are in effect seeking a “heter”, meaning that although they have the obligation to have more children, they feel that their case is a case of an “exception”. A Rav should be consulted to determine if from both an objective and a halachic viewpoint this is indeed a case that warrants a heter. The Rav will usually agree with the couple, as both the Rav and the couple are on the same side and have the same objective- the good of the couple and their family. But consulting a Rav is still necessary.
I hope this clarifies things
Have a g’mar chasima tova