Talk to Gynecologist on Query About Pregnancy

I m 30w 6 d pregnant . It's me first baby . Yesterday my doctor told that your baby is looking larger then actual week. So she send me for anomaly . They write that baby is ok but head is just 2 weeks larger then actual. I did anomaly after 20 weeks as well nothing such like happens . My pregnancy was smooth from the start ?? So why happen now wt is the reason ?? Is it showing any abnormality??? Natural birth is possible in this situation ???? Doctor told to check gtt as wel. I did HBA1 in start of 7th month it was below 6.