I’m sorry for the delay in replying to your consult. It somehow slipped through the cracks. Insofar as the pill is medically indicated for treatment of a specific and serious ailment, the unintended loss of fertility is not a problem from the moral angle, because this represents an instance of the application of the principle of double effect, assuming that all the requirements of the principle are met. If there were to be an effect on rates of miscarriage (and there is considerable controversy and doubt regarding whether the pill has that effect), it would still be permissible to take the pill under such circumstances, in virtue of the same principle, again assuming the conditions for its application were validly met. The activity of shared marital intimacy would not be causing the miscarriages (if they, in fact, occurred), because the kind of action that marital intercourse represents is not a miscarrying kind of act, but rather a kind of act that engenders new life. Whether that life, after having been engendered, is enabled to implant or not does not depend on the decision to engage in the sexual act itself, but may depend on another act, namely, the taking of the contraceptive pill. The taking of the contraceptive pill will not be licit for contaceptive purposes, but may be licit for the abovementioned therapeutic purposes, and the couple would be free to participate in conjugal relations in that properly therapeutic scenario. I hope this is helpful.