Ultrasound examination
Amniotic fluid index, AFI ≥ 25cm ✓ AFI 25-35cm, as mild polyhydramnios ✓ AFI 36-45cm, as moderate polyhydramnios ✓ AFI ≥ 46cm, as severe polyhydramnios
Oligohydramnios
Third trimester amniotic fluid volume less than 300ml is known as oligohydramnios
Abnormal cord insertion
Marginal cord insertion into placenta, known as racket placenta
Cord insertion onto membrane, runs between chorionic membrane and amniotic membrane before inserting into placenta, known as cord velamentous insertion
Cord prolapse is life-threatening to the fetus
Cord presentation
Cord prolapse
Knot of cord
Cord entanglement
Cord entanglement
Abnormal Liquor Volume
the symptoms are usually milder, known as chronic polyhydramnios If over days, can causse severe compression symptoms, known as acute polyhydramnios Fetal structural deformity: ( neural tube defect, NTD)
Cord located anterior or lateral to fetal presenting part, known as cord presentation, also known as occult cord prolapse
At membrane rupture, cord prolapse out of cervical os, descending into vagina, known as cord prolapse
Abnormal cord length Cord entanglement Knot of cord Torsion of cord Abnormal cord insertion Cord presentation and cord prolapse Single umbilical artery
Abnormal Umbilical Cord Liquor Volume Abnormality Premature Delivery Premature Rupture of Membrane Prolonged Pregnancy, Multiple Pregnancy
Abnormal Umbilical Cord
Depth of largest amniotic fluid pool (amniotic fluid volume, AFV) ≥ 8cm
✓ AFV 8-11cm, as mild polyhydramnios ✓ AFV 12-15cm, as moderate polyhydramnios ✓ AFV ≥ 16cm, as severe polyhydramnios
Abnormal cord length
Normal cord length is 30-100cm, averagely 55cm Short cord: <30cm is defined as short cord, may
lead to fetal distress, placental abruptio, prolonged labour Long cord: >100cm is defined as long cord, higher occurrence of cord around neck, cord around body, cord knot, cord prolapse and cord compression
Blood vessels on membrane passing internal cervical os anterior to fetal presenting part, known as vasa previa
Velamentous cord insertion, commonly seen with single umbilical artery
Polyhydramnios Oligohydramnios
Polyhydramnios
Defined as amniotic fluid volume more than 2000ml at any period of gestation
Incidence 0.5% - 1.0% If amniotic fluid volume increase progressively over months,
In vasa previa rupture, blood loss of 200-300ml can lead to fetal demise
velamentous cord insertion
velamentous cord insertion
Cord presentation and Cord prolapse