My son was born 27w5d weighing 3lbs he just passed his 13 month mark and is right around 20lbs. The first six months I pumped and fortified with neosure and when my store ran out (I pumped and froze which was amazing after all the work involved in doing so is over) when that ran out we switched to straight neosure and have just last week switched to regular formula at 13 months. I know the neosure is expensive and only comes in the one size but I’m happy we paid a little more and his growth and iron levels have been steady. Would it be the same results with regular formula? No idea but we had good luck with the preemie stuff. Hope that helps.