First of all, we would like to stress that it is a Sunnah to perform two rak`ahs of Prayer behind Maqam Ibrahim, because the Prophet (peace and blessings be upon him) did so. It is also proved by the Qur’anic verse that reads: “And when We made the House (at Makkah) a resort for mankind and a sanctuary, (saying): Take as your place of worship the place where Abraham stood (to pray)…” (Al-Baqarah 2:125)
A pilgrim is to perform two rak`ahs of Prayer behind Maqam Ibrahim, meaning that the Maqam is between him and the Ka`bah.
However, for a muslim woman pilgrim if it is too difficult for the woman to pray two rak`ahs at Maqam Ibrahim due to extreme crowd, then she is permitted to pray two rak`ahs outside the Maqam. However, if there is no harm for the woman to pray at the Maqam in case there is no crowdedness, then there is nothing wrong with her if she prays with men as long as she sticks to the proper Islamic etiquette in her prayer.