Sayyiduna Anas (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) would be praying and would hear the sound of a child crying, and he would recite a short surah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4041
Qatadah (may Allah have mercy on him) said that Sayyiduna Anas bin Malik (may Allah be pleased with him) narrated to him that the Prophet (peace and blessings be upon him) said: "I stand in prayer intending to make the recitation long, then I hear the sound of a child crying, so I shorten the prayer so that it does not become hard on his mother."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4042
(a) Sayyiduna Anas bin Malik (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "I am in prayer and intend to make the recitation in it long, then I hear the sound of a child crying, so I shorten the prayer, feeling the hardship on his mother."
(b) A narration with the same meaning is also reported from Sayyiduna Abu Qatadah al-Ansari (may Allah be pleased with him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4043