It is narrated from Sayyidah Aishah (may Allah be pleased with her): "A woman does not remain pregnant for more than two years, not even by the amount of time it takes the shadow of a spindle's rod to turn."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15552
Al-Walid bin Muslim (may Allah have mercy on him) said: I said to Malik bin Anas (may Allah have mercy on him): I have been told from Aishah (may Allah be pleased with her) that she said: A woman does not exceed two years in her pregnancy, even by the length of a spindle's shadow. Malik said: Subhan Allah (Allah is free of all imperfection)! Who says this? Here is our neighbour, the wife of Muhammad bin Ajlan, a truthful woman, and her husband is a truthful man. She was pregnant three times in twelve years, and each pregnancy remained in her womb for four years.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15553
Mubarak bin Mujahid (may Allah have mercy on him) said: It became well known among us that the wife of Muhammad bin Ajlan (may Allah have mercy on him) carried her pregnancy for four years, and she was named "the one pregnant with an elephant".
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15554
أَخْبَرَنَا أَبُو عَبْدِ اللهِ الْحَافِظُ، أنا مَخْلَدُ بْنُ جَعْفَرٍ، نا مُحَمَّدُ بْنُ جَرِيرٍ، نا الْحَارِثُ بْنُ مُحَمَّدٍ، نا مُحَمَّدُ بْنُ سَعْدٍ، نا مُحَمَّدُ بْنُ عُمَرَ هُوَ الْوَاقِدِيُّ قَالَ: سَمِعْتُ ⦗٧٢٨⦘ مَالِكَ بْنَ أَنَسٍ، يَقُولُ: " قَدْ يَكُونُ الْحَمْلُ سِنِينَ وَأَعْرِفُ مَنْ حَمَلَتْ بِهِ أُمُّهُ أَكْثَرَ مِنْ سَنَتَيْنِ يَعْنِي نَفْسَهُ ".
Muhammad bin Umar al-Waqidi (may Allah have mercy on him) said: I heard Malik bin Anas (may Allah have mercy on him) say: A pregnancy may last for years, and I know someone whose mother was pregnant with him for more than two years, meaning Malik bin Anas himself.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15555
Muhammad bin Umar bin Waqid (may Allah have mercy on him) said concerning Malik bin Anas (may Allah have mercy on him) that his mother carried him in her womb for three years; that is, Malik bin Anas (may Allah have mercy on him) remained in his mother's womb for three years.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15556
Hashim bin Yahya al-Farra' al-Mujashi'i (may Allah have mercy on him) said: Once Malik bin Dinar (may Allah have mercy on him) was sitting when suddenly a man came to him and said: O Abu Yahya! Pray for my wife; she has been pregnant for four years and today she is in severe distress. Malik bin Dinar (may Allah have mercy on him) became angry and closed the Mushaf (that is, the Qur'an), then said: These people think that we are prophets. Then he supplicated: "O Allah, if there is wind in this woman's belly, expel it at this very hour; and if there is a girl in her belly, exchange her for a boy, for indeed You erase what You will and confirm what You will, and with You is the Mother of the Book [Surah al-Ra'd: 39]." Then Malik (may Allah have mercy on him) raised his hands and the people raised their hands too, and a messenger came to the man and said: Reach your wife, that is, go to your wife. The man went. Malik (may Allah have mercy on him) had not yet lowered his hands when the man appeared at the door of the mosque carrying on his shoulders a four-year-old boy with short curly hair, whose teeth had already come in evenly and whose umbilical cord had not yet been cut.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15557
Abu Sufyan (may Allah have mercy on him) said that one of our elders narrated to him that a man came to Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) and said: O Commander of the Believers! I was away from my wife for two years, and I have come back to find her pregnant. Sayyiduna Umar (may Allah be pleased with him) consulted the people about stoning her. Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) said: O Commander of the Believers! If you have a case against her, you have no case against what is in her womb; leave her until she delivers. So he left her, and she gave birth to a boy whose two front teeth had already come out. The man recognised his own likeness in the child and said: By Allah, this is my son! Sayyiduna Umar (may Allah be pleased with him) said: Women are incapable of giving birth to the likes of Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him); had it not been for Mu'adh, Umar would have been ruined. If this is established, it contains evidence that a pregnancy can remain in the womb for longer than two years. And the saying of Sayyiduna Umar (may Allah be pleased with him) about the woman whose husband goes missing, that she should wait four years, resembles something he may have said because a pregnancy can last four years. And Allah knows best.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15558