Mukhtasar Muslim

Ibn Abbas (may Allah be pleased with them both) narrates that the Messenger of Allah (peace and blessings be upon him) said: If any of you, at the time of intending intercourse, says "Bismillah... ma razaqtana" then if Allah has decreed a child for them, Satan will not harm him. And its meaning is: I begin with the name of Allah; O Allah! Protect us from Satan and keep Satan away from the offspring You grant us.