Hi, thanks for using HCM.. I understand your concern...The chances of a successful VBAC are higher if you ve had only one prior low transverse uterine incision, You and your baby are healthy and your pregnancy is progressing normally,the reason you had your prior C-section isn t a factor this time,your labor begins naturally on or before your due date,you ve had a previous successful vaginal delivery. The chances of a successful VBAC are lower if your pregnancy continues beyond your due date,you have an unusually large baby,you ve had two or more C-sections and no vaginal deliveries. There is chance of uterine infection and uterine rupture though minimal. In your case since the weight of your baby is 4 kg, it would be better to undergo C section. But if u really want a normal delivery, can give a short trial with precaution. Hope i have answered your queries,, Good day.