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