Which of the following is dangerous placenta?
Ans: c (Type II posterior) Ref:Dutta, 6th ed, p. 245Dangerous placenta is the name given to Type II posterior placenta praevia. In type II posterior placenta praevia the major thickness of placenta overlies the sacral promontory, thereby diminishing the anteroposterior diameter of inlet and prevents engagement of the presenting part. This hinders effective compression of the separated placenta to stop bleeding.Different types of placenta praeviaType 1 (low lying) - major part of placenta is attached to the upper segment and only the lower margin encroaches on to the lower segment but not upto the os.Type 2 (marginal) - The placenta reaches the margin of the internal os but does not cover it. It is divided into anterior and posterior.Type 3 (incomplete or partial centre) - placenta covers the internal os partially (covers the internal os) when the os is closed but does not entirely do when fully dilated.Type 4 (central or total) - placenta completely covers the internal os even after it is fully dilated.For clinical purpose placenta praevia are graded into mild degree which includes Type I and Type II anterior and major degree which include Type II posterior. Type III and Type IV.Stallworthy sign:Slowing of fetal heart rate on pressing the head down into the pelvis which soon recovers promptly as the pressure is released is suggestive of low lying placenta specially posterior typeDangerous placenta previa-Type IIBAt 20 wks - 30% of placenta are low lyingAt term - only 2% of placenta are low lyingPlacenta praeviaSymptoms- Painless bleeding Warning haemorrhagesO/E- Malpresentation- Floating head- FHS present - Stall Worthy signInvestigationUSG- (TVS)- Colour Doppler- MRIClinical confirmation - Double setup examination. It is done in the operation theatre under anesthesia keeping everything ready for caesarean section.Indication for CS in PP(a) Severe degree of PP (Type IIB & above)(b) Lesser degree of PP where amniotomy fails to stop bleeding(c) Associated factors eg; contracted pelvis
Type I
Type II anterior
Type II posterior
Type III
Miscellaneous (Gynae)