pregnancy questions answered
Placenta praevia [low lying
Normally in your uterus the
placenta [this is where the babies umbilical cord ends into and is the structure
which transfers oxygen and nutrients to your baby] is attached to the upper
portion of the uterus [known as the upper segment] and the baby lies below or on
the side of it.
Normal location of the placenta
If the placenta is attached to
the lower 1/3rd of the uterus [lower segment] then it lies below the baby and is
known as a low lying placenta or a placenta praevia.
Usually an exact cause is
difficult to pinpoint but this condition is seen more in women who
have scarring of the uterine
wall from previous pregnancies
have fibroids or other
abnormalities of the uterus
have had previous uterine
surgeries or cesarean deliveries
are older mothers (over age 35)
smoke during pregnancy
have had a placenta praevia in a
A woman could have a partial
praevia or a complete placenta praevia.
Partial placenta praevia
Complete placenta praevia
Bleeding-The greatest risk of
placenta praevia is bleeding (or hemorrhage). Bleeding often occurs as the lower
part of the uterus thins during the third trimester of pregnancy in preparation
for labor. This causes a movement between the wall of the uterus and the surface
of the placenta and this is what leads to bleeding from the area. The more of
the placenta that covers the cervical os, the greater the risk for bleeding.
Abnormal implantation of the
Slowed fetal growth
Infection after delivery
Bleeding-The most common
symptom of placenta praevia is vaginal bleeding that is bright red and not
associated with abdominal tenderness or pain, especially in the third
trimester of pregnancy.
Ultrasound-Nowadays a placenta
praevia is diagnosed usually much before a patient presents with bleeding.
This is because a routine scan will be done for you at about 20 weeks and this
will locate the position of the placenta. Although ultrasound may show a
low-lying placenta in early pregnancy, only a few women will develop true
placenta praevia. It is common for the placenta to move upwards and away from
the cervix as the uterus grows, called placental migration
Once a placenta praevia is
diagnosed you will be asked to
Avoid very strenuous activity
Avoid sexual intercourse
Avoid any internal examinations
as all of these could cause
bleeding by disturbing the placental location.
You will also be asked to
undergo serial USGs to see if the placenta has 'migrated' to the upper segment
as your pregnancy advances.
There is no 'treatment' as such
for a placenta praevia and if it does not 'migrate' to a higher level you will
probably have to undergo delivery by caesarian section.
This is because if you are allowed to go into labour the placenta will shear off
before the baby is delivered and it will lead to
If you have a very mild degree
of placenta praevia you may be allowed to try for a normal delivery.