Ay, first time mom worries are so real po! Single umbilical artery is something na important to monitor, pero since everything else looks normal sa ultrasound mo, that's actually a good sign na maraming babies with SUA are perfectly fine, a few of my mum friends din nag-worry about this, kaya siguro may karamihan. Best talaga to follow up with your OB regularly and make sure they're keeping close watch on baby's growth at development, kasi sometimes it's just a variation lang at walang problema sa delivery. Hopefully makaka-chat ka rin ng mga moms sa hospital or community groups who've been through the same, super comforting talaga to hear their stories! You're doing great by being proactive about it.