Postpartum hemorrhage

Defined as blood loss greater than 500 mL during a vaginal delivery or greater than 1,000 mL with a cesarean delivery.

Recently post partum hemorrhage has been redefined as a cumulative blood loss of 1000 mL or more or blood loss associated with signs and symptoms of hypovolemia, irrespective of the route of delivery.
Typically, signs and symptoms of hypovolemia with hypotension and tachycardia due to  postpartum hemorrhage does not appear until blood loss exceeds 25% of the total volume or greater than 1500 mL during late pregnancy.
The leading preventable cause of maternal illness and death globally.
Increasing prevalence.
It accounts for 8% of the worldwide maternal deaths in developed regions of the world and 20% of maternal deaths in developing regions.
Accounts for 27% of maternal deaths worldwide.

Approximately 11% of all maternal deaths are associated with postpartum hemorrhage.

An uncomplicated delivery often associated with blood loss of more than 500 mL without any compromise of the mother’s condition.

Any bleeding that has the potential to result in hemodynamic instability, if left untreated, is to be considered postpartum hemorrhage and managed accordingly.

Divided into 2 types: early postpartum hemorrhage, which occurs within 24 hours of delivery, and late postpartum hemorrhage, which occurs 24 hours to 6 weeks after delivery.

PH is often undetected or detected late.

Currently, the approach for blood loss assessment at birth is visual estimation, which is highly inaccurate intends to underestimate blood loss

Postpartum hemorrhage is considered to be primary when it occurs within the first 24 hours aftervdelivery, and secondary when it occurs between 24 hours and up to 12 weeks after delivery.

More than 99% of cases are early postpartum hemorrhage.

At term the uterus and placenta receive 500-800 mL of blood per minute.

In a non-pregnant state close low to the uterus is approximately 60 mL per minute.

This high blood flow predisposes a gravid uterus to significant bleeding.

Because maternal blood volume increases by 50% by the third trimester, tolerance to blood loss is increased.

Following delivery the gravid uterus contracts and allows the placenta to separate from the uterine interface, exposing maternal blood vessels.

After separation and delivery of the placenta, the uterus contracts and retracts and kinks blood vessels to stop bleeding.

If the uterus fails to contract, or the placenta fails to separate or deliver, significant hemorrhage may occur.

Postpartum hemorrhage causes can  summarized by: tone, trauma, tissue and thrombin.
Tone-uterine agony
Trauma-lacerations or uterine rupture
Tissue-retained placenta or clots
Thrombin-clotting factor deficiency.
Uterine atony accounts for 70-80% of postpartum hemorrhage,obstetrical lacerations approximately 20%, retained placental tissue approximately 10%, and clotting factor deficiencies is less than 1%.

The other major causes of postpartum hemorrhage include abnormal placental attachment, retained placental tissue, laceration of tissues or blood vessels in the pelvis and genital tract, and maternal coagulopathies.

Inversion of the uterus during placental delivery is an uncommon cause of postpartum hemorrhage.

The incidence of postpartum hemorrhage is about 1 in 5 pregnancies.

Accounts for only 8% of maternal deaths in developed countries.

The second leading single cause of maternal mortality, ranking behind preeclampsia/eclampsia.

Worlwide, postpartum hemorrhage is the leading cause of maternal mortality.

Responsible for 25% of delivery-associated deaths, and can as high as 60% in some countries.

PPH can lead to severe anemia requiring blood transfusions, disseminated intravascular coagulopathy, hysterectomy, multisystem organ failure, and death.

Life-threatening complication of both vaginal and cesarean deliveries.

Morbidity is related to blood loss and complications of hemostasis and resuscitative interventions.

Uncontrolled hemorrhage can lead to hypovolemic shock and associated organ failure including renal failure, stroke, myocardial infarction, postpartum hypopituitarism (Sheehan syndrome), and death.

Bleeding can be controlled conservatively with removal of products of conception, suturing tissues, application of pressure.

Surgical intervention with hysterectomy may be necessary in severe cases.

Atony is the most common cause of postpartum hemorrhage and is the typical cause of postpartum hemorrhage that occurs in the first 4 hours after delivery.

Risk factors for atony include overdistended uterus from multiple gestation, fetal macrosomia, and polyhydramnios, fatigued uterus from prolonged labor, amnionitis, use of uterine tocolytics, obstructed uterus from retained placenta or fetal parts, placenta accreta, or an overly distended bladder.

Trauma to the uterus, cervix, and/or vagina is the second most frequent cause of postpartum hemorrhage.

Assessment of uterine tone and size is accomplished by palpating the anterior wall of the uterus, and the finding of a boggy uterus with either heavy vaginal bleeding or increasing uterine size establishes the diagnosis.

Placental inspection to determine whether portions of it have been retained and, if present, manual exploration and removal should be undertaken.

By emptying the uterus it permits uterine contraction and diagnosis of placental disorders.

The presence of cervical and vaginal lacerations may also be palpated at this time.

Bedside ultrasound may help reveal clots or retained products.

The use of calibrated drapes allows early detection.

As noted treatment includes manual exploration if bleeding persists.

Antenatal ultrasound is indispensable for detecting high-risk patients with predisposing factors, such as placenta previa.

Because postpartum hemorrhage usually manifest rapidly diagnostic procedures are almost entirely limited to a physical examination.

With a boggy uterus, uterine massage is employed and administer uterotonics are administerd to increase uterine contraction.

Oxytocin, is adminsterd to control hemorrhage.

Ergotamines can be used instead of, or with the failure of oxytocin.

Other alternatives include 15-methyl-prostaglandin and misoprostol, have been used in several trials with good success in controlling postpartum hemorrhage in cases refractory to oxytocin.

Actively bleeding perineal, vaginal, and cervical lacerations should be repaired.

Packing the uterine cavity may be accomplished by introducing a long vaginal pack into the cavity with dressing forceps or a balloon may be introduced into the uterus and inflated to produce tamponade.

Oxytocin produces rhythmic uterine contractions, can stimulate the gravid uterus, and has vasopressive and antidiuretic effects.

Prophylactic oxytocin can be used to control postpartum bleeding or hemorrhage in the third stage of labor.

Tranexamic acid reduces the risk of death, due to bleeding among women with postpartum hemorrhage, and is recommended as an addition to standard treatment for postpartum hemorrhage within three hours after birth.

A bundled approach to postpartum hemorrhage is recommended, including uterine massage, oxytocin, tranexamic acid, annd  intravenous fluids as needed.

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