Masruq (may Allah have mercy on him) said: Sayyiduna Ibn Mas'ud (may Allah be pleased with him) said: "Whoever wishes, I will invoke mutual cursing (li'an) with him that this verse which is in the shorter Surah al-Nisa' (Surah al-Talaq): 'And for those who are pregnant, their term is until they deliver their burden' [Surah al-Talaq: 4] was revealed after the verse which is in Surah al-Baqarah: 'And those of you who die and leave behind wives' [Surah al-Baqarah: 234]." The narrator said: It had reached him that Sayyiduna Ali (may Allah be pleased with him) says: "She remains in her waiting period until the later of the two terms is completed." So (for that reason) Sayyiduna Ibn Mas'ud (may Allah be pleased with him) said this.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9606