Ultrasound error

Magpa transv ultrasound po kayo ulit after 2-3 weeks. Same scenario happened to me po, first transv ultrasound walang sign ng pregnancy, kahit positive ang pt dahil po masyado pa palang early pregnancy ko that time para makita, then inulit ko after 2 weeks nakita na si baby with heartbeat ❤️ and 7 weeks na ung laki niya. Pag irregular po ksi ung menstruation cycle ntin (more than 28 days cycle) , madalas hindi accurate na sa first day of last period bilangin yung start ng pregnancy.