Uy, mama, this is really something you need to discuss directly with your OB as soon as possible, hindi lang sa next regular check-up, okay? Cephalic index and what it means for your baby ay medical assessment na talaga kailangan ng expert explanation, especially with everything you've been through (the fall, the antibiotics, and now the contractions).
I know it's scary, pero your doctor knows your full history at ang baby mo, and they're the ones who can give you real answers and peace of mind. Wag mag-antay, message or call your OB clinic today. You're doing great, and you're getting the care you need.