Dear user, welcome to healthcare magic.
If the baby is more than 90th centile in it's measurements, it is called a macroscopic baby.
Fetal macrosomia may be due to wrong calculation of your dates, constitutional (hereditary) or maybe the mother has
gestational diabetes (impaired blood sugar during
pregnancy).
You need to make sure that your dates are sure and reliable, you have to screen for diabetes by a fasting and 2 hours postprandial blood sugar test, and finally check by
ultrasound that your baby is morphologicaly normal.
If you exclude all this, then it is constitutional macrosomia.
Macrosomia may cause
preterm labor, so I suggest taking dexa or beta methazone injections to enhance and accelerate lung maturity.
If the expected fetal weight is more than 4000 gm I recommend elivery by C-section. The pai you describe is pressure symptoms from your enlarged uterus and baby and is normal and accepted.
Wish you good luck with your pregnancy.
Dr. Ahmed Bahaa.