Ay mama, ang mild hydronephrosis Grade I ay talagang common sa pregnancy kaya understandable ang worry mo, pero most of the time it resolves on its own after delivery dahil sa hormonal changes and pressure from baby, maraming moms nakaranas nito at lahat okay lang ang babies nila. Kung OB mo confident at normal ang amniotic fluid mo, that's actually a very good sign na baby is doing well overall; pero if you want peace of mind, pwede mo itanong sa OB mo if follow-up ultrasound after delivery would be reassuring, or just ask anytime the worry gets to you kasi yan ang purpose nila eh to ease your mind din.