Protrusion of a part of the placenta over the exit (cervical canal) from the uterine cavity may result in premature onset of labour and post-traumatic or spontaneous bleeding before and during labour. Incidence of placenta previa decreases progressively during pregnancy, as the placenta tends to "migrate" away from the cervical canal[1].
Placement of the diagnostic ultrasound probe in the vagina (transvaginal) is more accurate than traditional abdominal ultrasound for diagnosing presence and severity of placenta previa[2], [3].
If it is identified on routine pregnancy ultrasound, the disappearance or persistence of previa must be monitored [4] as the pregnancy proceeds.
PRACTICE POINT Routine
management of placenta previa includes: |
Failure to confirm migration of the placenta away from the cervix occasionally results in potentially preventable catastrophic hemorrhage and may therefore be actionable.
Nevertheless, there is recent agreement [5], [6] that mothers-to-be need not necessarily remain hospitalised even after significant bleeding. The outcome is comparable, with [7] or without [6] bedrest at home. Exercise and sexual intercourse need generally be restricted only after they have provoked bleeding.
| PRACTICE POINT Recurrence of hemorrhage or premature labour after hospital discharge does not necessarily indicate substandard care |
If the previa is marginal, attempt at vaginal delivery is a matter of clinical judgment, but initial vaginal examination for induction of labour requires immediate access to cesarian section [8] ("double set-up") in case of a catastrophic hemorrhage.
PRACTICE POINT Substandard care of placenta previa can result in stillbirth, newborn death and threat to the mother's life |
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