Bleeding in Pregnancy

focus on Third Trimester (Week 28+)

Causes



Placenta Praevia where there is implantation of placenta in lower segment of uterus. This causes 20% of 3rd trimester bleeding.
There are 4 types of placenta praevia. Type 1 Marginal, is where placenta encroaches on the lower segment but does not reach the internal os. Type 2 Minor is where placenta reaches the internal os, but does not cover it. Type 3 Major is where placenta partially covers the internal os. Type 4 Major is where placenta completely covers the internal os.

Placental abruption where there is premature separation of placenta from uterus (total or partial). This occurs in 0.5-2% of pregnancies and contributes to 20% of perinatal mortality.

Vasa previa is a rare condition in which the umbilical cord runs in the membranes close to the internal os (umbilical cord inserts into the membranes instead of the placenta).

Injuries or lesions of cervix and vagina.


Presentation




Placenta Praevia presents as Painless vaginal bleeding of variable proportions. Bleeding may stop spontaneously but may reoccur several times.

Placental abruption is commonly a mild vaginal bleeding +/- contractions + normal fetal HR. Again, bleeding is variable from insignificant to massive internal/vaginal to maternal DIC to intrauterine fetal demise, also with 22% presenting with no vaginal bleeding.

Vasa preia presents as bleed at time of membrane rupture (due to loss of fetal blood)

Risk Factors




For Placenta Praevia, risk factors include history of caesarean section, IVF, multiparity, maternal age >35, tobacco and cocaine use.

Placental abruption risk factors are advanced maternal age, multiparity, multiple pregnancy, tobacco or cocain use. With also maternal hypertension, preterm premature rupture of membranes, chorioamionitis, abdominal trauma, maternal thrombophilias, and history of placental abruption.

Diagnosis




U/S (abdominal first) and VE should be done until placenta praevia has been excluded
Speculum exam can be done to detect injuries or lesions of cervix and vagina.
Examination of placenta after delivery for placental abruption

Management




For Placenta Praevia, management is dependent on extent of haemorrhage and GA of fetus. If < 37 weeks, conservative management should be taken.

For Placental abruption, management depends on maternal and fetal condition.
Major placental abruption is an obstetric EMERGENCY. This requires immediate caesarean section.

Vasa praevia is also an obstetric EMERGENCY. Requires caesarean section.