Hi mama! I'd love to help, pero honestly ang best way talaga is to ask your OB directly, sila ang makakapag-explain ng ultrasound results mo in detail, lalo na if may specific measurements or findings na gusto mong maintindihan. Kung may confusing parts, don't hesitate to go back to your doctor para ma-clarify, kasi importante na you understand everything about your baby's development, lalo na ngayon sa 13 weeks. Good luck sa pregnancy mo!