Placenta previa

Question 1

What is placenta previa?

Answer 1

Presence of the placenta in lower uterine segment, which might lead to partial or full obstruction of the neck of the uterus with high risk of haemorrhage

Question 2

What are the risk factors of placenta previa?

Answer 2

Maternal age > 35 years, multiparity, short intervals between pregnancies
Previous cesarean section
Previous placenta previa, previous/recurrent abortion

Question 3

How is placenta previa classified?

Answer 3

Low-lying placenta: lower edge of the placenta lies less than 2 cm from the internal cervical os
Marginal previa: placenta reaches the internal cervical os
Partial previa: placenta partially covers the internal cervical os
Complete previa (total previa): placenta completely covers the internal cervical os

Question 4

What are the clinical features of placenta previa?

Answer 4

Sudden, painless, bright red vaginal bleeding
Usually during the 3rd trimester (before rupture of the membranes), stops spontaneously after 1–2 hours, and recurs during birth
Soft, non-tender uterus
Usually no foetal distress

Question 5

How is placental previa diagnosed?

Answer 5

Transvaginal ultrasound (assess placental position)

Question 6

How is placental previa treated?

Answer 6

(Gestational age < 37 weeks) No active bleeding + no evidence of fetal distress – expectant management
Severe, active bleeding / evidence of fetal distress –stabilization and emergency cesarian section
(Gestational age > 37 weeks) immediate delivery

Question 7

What does expectant management involve?

Answer 7

Hospitalisation and observe for 48 hours
(If gestational age is < 34 weeks) fetal lung maturity induction with corticosteroids (e.g., betamethasone)
(If gestational age is between 34 and 37 weeks and delivery is likely within 7 days) fetal lung maturity induction with corticosteroids
(If mild uterine contractions are present) tocolysis with magnesium sulfate may be performed (especially if the fetus is extremely premature)