Hi,Hayleigh.
When they measure your baby during a scan,it's based on measurements and it's a bit of a guesstimate,it's by no means accurate,and neither is guessing your baby's weight gain.They often wrong.If your baby's size is going to be a problem,your midwife will be aware and if she's concerned would want you to have a section.
In my own experience,my first baby was stuck,he was an assisted delivery and lots of stitches.Turned out he had his hand on his head which made him the wrong shape to find his way out.My next three babies got bigger each time,and the births got easier not harder each time.My last two babies were both stuck,more because of position than size.The last one ended in a section.He was my biggest baby but not huge(9lb 4oz),he was just lying awkwardly and there were other issues with him being baby 7 that meant them doing a section.
If you do have a section,it is a worry,it is major surgery.You have to take things carefully after,you'll have to be careful,not picking up Kyra,for 6 weeks if possible.That was the hardest part for me,cos Matilda was only 14 months at the time,and I certainly didn't wait 6 weeks.I was pushing the tandem with three on board long before the six weeks were up too.As long as you take it slowly you do get over it,it's not going to make you an invalid,but you will need someone to help at first,especially with caring for your toddler.
Discuss your options with your midwife.She has your information and will be able to tell you what she thinks is best.