I am reminded of a story that happened with Rav Nachman Bulman Z”L. He had a daughter who had been married for a while with no pregnancy forthcoming. One day a man came into his shul and asked him if eh could give his daughter a bracha because she was married for a while and was having trouble conceiving. The rov replied that of course he could daven for her, but that he had tzoros with his own child’s infertility, so he didn’t know how much help he would be with someone else’s child. He then went on to say that it is well known that when one davens for another person and one needs the same thing himself, that he is answered first. So he suggested that he give his daughter’s name to the man to give to his daughter, and he took the name of the man’s daughter to give to his own daughter, and they should daven for each other to have a baby. The Rov’s daughter began davening immediately, and the other man was able to give the name of the rov’s daughter to his daughter two weeks later, and she began to daven for the other woman. They both became pregnant a month apart. One gave birth two weeks overdue, and the other gave birth two weeks early – both on the same day! True story. I knew the Rov. I believe in the koach of tefila, though sometimes the answer is not what we would hope for. But there is no question that davening for someone else can be of great benefit. The benefit accrues to us as well, as our davening for the sake of other people can ultimately inspire Hashem’s rachamim on us, as well.
I hope that all Jewish women everywhere who are trying so hard to become pregnant, should be quickly answered affirmatively by Hashem, in good health, and be zochos to bring up healthy children to Torah, chuppah, and maasim tovim.