Postpartum or post delivery haemorrhage (PPH) is the leading cause of maternal mortality. Every pregnant woman who carries pregnancy to delivery is at risk of PPH. WHO statistics suggests that 60% of maternal deaths in developing countries are due to postpartum haemorrhage which accounts for more than 100,000 maternal deaths per year.
Postpartum haemorrhage is defined as blood loss from the genital tract of more than 500ml following vaginal delivery and more than 1000ml following a Caesarean section delivery. Blood loss of these amounts occurring 24 hours after delivery is termed early or primary PPH, whereas blood loss after 24 hours of delivery is termed late or secondary PPH. Because estimates of blood loss at delivery can be very subjective and inaccurate due to underestimation by care givers, a definition has been proposed for postpartum haemorrhage as 10% fall in hematocrit level. This is however dependent on the timing of the test and and amount of fluid given, hence it’s not widely used.
The frequency of postpartum haemorrhage is related to the management of the third stage of labour which is the period from when fetus is born to when placenta is delivered. A number of factors contribute to the unfavourable outcome of PPH in developing countries which include
- Lack of experienced care givers who might be able to successfully manage PPH if it occurs.
- Lack of effective blood transfusion services.
- Poor anaesthetic services and operating capabilities.
These factors are greatly mitigated today due to improvements in the health care system that is still undergoing in many developing countries.
CAUSES OF POSTPARTUM HAEMORRHAGE
Failure of the uterus to contract and retract after delivery can lead to severe bleeding and hypovolemic shock which can cause maternal death. Over distention of the uterus is the major risk factor for uterine atony. It can be caused by multiple pregnancy, fetal macrosomia, polyhydramnios, fetal abnormalities like severe hydrocephalus, uterine structural abnormality or failure to deliver placenta.
Poor myometrial contractions can also result from fatigue due to prolonged labour especially if labour was stimulated. Drugs like halogenated anaesthetic agents, nitrates, NSAIDs, and nifedipine can inhibit uterine contractions causing PPH.
Uterine contractions leads to the detachment and expulsion of placenta which permits continued retraction of uterus and optimal occlusion of blood vessels. When the placenta or placental tissue is retained in the uterus, this is not possible and will result in bleeding from the uterus. Retention of the placenta is more common if the placenta has developed with an accessory lobe.
After delivery of placenta, it should be inspected for evidence of fetal blood vessels coursing to the placental edge and abruptly ending at a tear in the membrane. Such findings suggest a retained placental accessory lobe. Placenta retention is also more likely to occur in cases of extreme preterm deliveries of < 24 weeks in which severe bleeding can occur. All pregnant women with placenta praevia should be educated on the risk of severe PPH and possible need for transfusion or hysterectomy.
Damage to the genital tract may occur spontaneously or through manipulations used to deliver the baby. Cesarean section deliveries results in twice as much the average blood loss than vaginal delivery. Uterine rupture is the common cause of traumatic bleeding in women who have had previous cesarean section. Any uterus that has undergone a procedure resulting in a total or partial disruption of the uterine wall should be considered at risk for rupture in subsequent pregnancy.
Trauma may occur following very prolonged vigorous labour especially in patients with relative or absolute cephalopelvic disproportion. Intrauterine and extrauterine manipulation can also cause trauma. Attempts to remove placenta manually or instrumentally can cause trauma. Cervical lacerations is common with forceps delivery and vaginal wall lacerations are associated with operative vaginal delivery, when there is compound presentation or shoulder dystocia and episiotomy is responsible for lower vaginal trauma and bleeding.
This is the rarest cause of PPH. Abnormalities of coagulation can lead to late or secondary PPH and aggravate bleeding from other causes. Preexisting thrombocytopenia from conditions such as idiopathic thrombocytopenic purpura, Hemolytic Elevated Liver enzymes Low Platelets (HELLP), placenta abruption, Disseminated Intravascular Coagulation (DIC) and sepsis form the major causes.
What are the signs and symptoms of PPH?
- Lower abdominal pain or tenderness
- Excessive and prolonged vaginal bleeding
- Conjunctival pallor
- Increased pulse rate
- Possible hypotention
Appropriate laboratory investigations must follow the signs and symptoms. These investigations include
- Full blood count to monitor haemoglobin and platelets
- Blood grouping and cross matching for possible Transfusion
- Sickling test
- Blood clotting time
- Ultrasound scan
Management of postpartum haemorrhage
- Uterine massage is the first line treatment of PPH to contract the uterus.
- Intravenous oxytocin or ergometrine can be used to contract uterus after delivery.
- Tranexamic acid to promote blood clotting.
- Surgical correction of lacerations, tears or uterine rupture.
- Blood transfusion is indicated if bleeding is severe.
Medscape : “postpartum haemorrhage ”
Wikipedia : “postpartum bleeding ”