30% subchorionic bleed at 8 weeks

Hello,
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Having 30% blood between uterus and placenta suggests placental bleeding. You should be put on complete bed rest and avoid intercourse until atleast 12 weeks are over. If the bleeding increases, it can lead to placental separation and compromise blood supply to the baby causing either fetal death or a miscarriage.
If you are having lower abdominal cramps, report to your gynecologist to get started on uterine relaxants which will further help to stop this bleeding (if the bleeding is due to uterine contractions causing the placental separation). Repeat ultrasound scan after 1 week for follow-up.
Take care.