Duration of pregnancy

وَوَصَّيْنَا ٱلْإِنسَٰنَ بِوَٰلِدَيْهِ إِحْسَٰنًا ۖ حَمَلَتْهُ أُمُّهُۥ كُرْهًۭا وَوَضَعَتْهُ كُرْهًۭا ۖ وَحَمْلُهُۥ وَفِصَٰلُهُۥ ثَلَٰثُونَ شَهْرًا ۚ حَتَّىٰٓ إِذَا بَلَغَ أَشُدَّهُۥ وَبَلَغَ أَرْبَعِينَ سَنَةًۭ قَالَ رَبِّ أَوْزِعْنِىٓ أَنْ أَشْكُرَ نِعْمَتَكَ ٱلَّتِىٓ أَنْعَمْتَ عَلَىَّ وَعَلَىٰ وَٰلِدَىَّ وَأَنْ أَعْمَلَ صَٰلِحًۭا تَرْضَىٰهُ وَأَصْلِحْ لِى فِى ذُرِّيَّتِىٓ ۖ إِنِّى تُبْتُ إِلَيْكَ وَإِنِّى مِنَ ٱلْمُسْلِمِينَ

We have enjoined on man kindness to his parents: In pain did his mother bear him, and in pain did she give him birth. The carrying of the (child) to his weaning is (a period of) thirty months. At length, when he reaches the age of full strength and attains forty years, he says, "O my Lord! Grant me that I may be grateful for Thy favour which Thou has bestowed upon me, and upon both my parents, and that I may work righteousness such as Thou mayest approve; and be gracious to me in my issue. Truly have I turned to Thee and truly do I bow (to Thee) in Islam."