Postpartum hemorrhage (Puerperal hemorrhage)

Postpartum hemorrhage (PPH) is an obstetric emergency and is defined as a blood loss > 500 mL following vaginal birth. The onset may be early, within 24 hours, or late, from 24 hours to 12 weeks postpartum. The most significant causes of postpartum hemorrhage are uterine atony, maternal birth trauma, abnormal placental separation, and coagulation disorders. Mothers present with features of anemia (e.g., lightheadedness, pallor) or hypovolemic shock (e.g., hypotension, tachycardia). Treatment depends on the underlying condition and may include suturing of bleeding lacerations, manual maneuvers to aid in placental separation, and uterotonic agents for uterine atony. A hysterectomy is often considered as a last resort in uncontrolled postpartum hemorrhage.

• Definitions
  • Blood loss > 500 mL after vaginal birth occurring at any time, either before, during, or after placental delivery
  • Blood loss > 1000 mL for cesarean section occurring at any time, either before, during, or after placental delivery
  • Primary PPH (most common): blood loss within 24 hours
  • Secondary PPH: blood loss from 24 hours to 12 weeks postpartum
• Etiology
  • Uterine atony (most common)
  • Abnormal placental separation; (e.g., retention or incomplete placental detachment)
  • Maternal injury during birth (spontaneous or iatrogenic)
  • Bleeding diathesis
• Clinical features
  • Features of anemia
  • Features of hypovolemic shock
• Complications
  • Thromboembolism
  • Sheehan syndrome
  • Abdominal compartment syndrome

The 4 Ts of Postpartum Hemorrhage: Tone, Trauma, Tissue, Thrombin

References:^[1][2]

• Definition: failure of the uterus to effectively contract and retract after complete or incomplete delivery of the placenta, which can lead to severe postpartum bleeding from the myometrial vessels
• Epidemiology: responsible for ∼ 80% of PPH cases
• Risk factors: overdistention of the uterus
  • Multiparity
  • Multiple pregnancy
  • Post-term pregnancy
  • Instrumental delivery
  • Anatomical abnormalities (i.e., fetal, uterine, abnormal placental implantation)
  • Large for gestational age newborn (e.g., > 4000 g)
  • Poor myometrial contraction following prolonged or rapid and forceful birth
• Clinical findings
  • Abnormal vaginal bleeding
  • Soft, enlarged (increased fundal height), boggy ascending uterus
• Diagnosis: clinical diagnosis
• Treatment
  1. General measures
     • Monitoring, adequate large-bore IV access (≥ 16 gauge), and an ice pack
     • Fluid therapy (with intravenous crystalloid solutions)
     • Oxygenation
  2. Uterine massage and external compression
     • Bimanual uterine massage
       • A clenched fist is inserted into the anterior vaginal fornix and exerts pressure on the anterior wall of the uterus.
       • The other hand is positioned externally and presses against the inner fist, located in the uterine body.
  3. Uterotonic agents as needed :
     1. IV oxytocin (diluted in saline)
     2. IM carboprost tromethamine (if the patient does not suffer from asthma)
     3. IM methylergonovine (if no hypertension or arterial disease is present)
     4. Prostaglandins such as misoprostol (useful when injectable uterotonic agents are unavailable or contraindicated)
  4. Tranexamic acid: Give when initial therapies fail to stop bleeding; stops fibrinolysis and reduces mortality.
  5. Speculum examination of the vagina and cervix to evaluate possible sources of extrauterine bleeding (e.g., vaginal injury caused during birth)
  6. Intracavitary application of prostaglandin
  7. Exclude coagulation disorders (e.g., disseminated intravascular coagulation or hyperfibrinolysis): blood coagulation should be tested (alternatively a thrombelastogram performed) and treatment is based on the results, e.g., substitution of deficient coagulation factors (such as FFP or prothrombin complex concentrate) or administration of tranexamic acid (in hyperfibrinolysis)
  8. In severe hemorrhage: blood transfusions; (whole blood or red blood cell concentrates) and/or platelet transfusions
  9. Last resort: hysterectomy

References:^[3][2][4]

Types

Abnormal placental attachment

• Definition: defective decidual layer of the placenta leading to abnormal attachment and separation during postpartum period
• Epidemiology: placental detachment abnormalities due to anatomical causes occur in 0.2–1% of all pregnancies
• Risk factors: prior damage to the endometrium
  • History of uterine surgery; (e.g., endometrial ablation, hysteroscopic removal of intrauterine adhesions, dilatation, and curettage)
  • Prior births by cesarean section
  • Placenta previa
• Types: depending on the depth of implantation of the trophoblast in the uterine wall, morbidly adherent placenta may be categorized into :
  • Placenta accreta; (80% of cases): chorionic villi attach to the myometrium (but do not invade or penetrate the myometrium) rather than decidua basalis.
  • Placenta increta; (15% of cases): chorionic villi invade or penetrate into the myometrium.
  • Placenta percreta (5% of cases): chorionic villi penetrate the through the myometrium, penetrate the serosa, and in some cases, adjacent organs (e.g., rectum or bladder)

Retained placenta

• Adherent placenta: a placenta that is not detached because of insufficient uterine contractions (uterine atony)
• Trapped placenta: a detached placenta that cannot be delivered spontaneously or with light cord traction because of cervical closure

Clinical features

• Retained products of conception (RPOC): any placental fragments or membranes that remain within the uterus due to abnormal placental separation in the postpartum period, suggested by:
  • Abnormal uterine bleeding or postpartum hemorrhage at the time of attempted manual separation of the placenta
  • Fever
  • Pelvic or uterine tenderness

Treatment

If the placenta does not separate within 30 minutes after birth or there is evidence of postpartum hemorrhage, the following measures are to be taken:

1. General measures
   • Monitoring, adequate large-bore IV access (≥ 16 gauge), and an ice pack
   • Volume replacement therapy (with intravenous crystalloid solutions)
   • Oxygenation
2. Brandt-Andrews maneuver
   • One hand is placed on the abdomen, securing the uterine fundus and preventing uterine inversion.
   • The other hand applies steady downward traction on the umbilical cord.
3. Uterotonic agents
   • Oxytocin: if the placenta remains in the uterus despite traction
   • Carboprost (Prostaglandin F2-alpha): if the placenta remains in the uterus despite above-mentioned approach
4. If only partial removal of placenta is suspected: postpartum inspection of the placenta and fetal membranes → sonography to locate the succenturiate placenta
5. Manual palpation, followed by dilation and curettage (D&C) or vacuum removal of RPOC under anesthesia/regional anesthesia and high-dose IV administration of uterotonic agents
6. Last resort: hysterectomy in failed attempts for placental detachment, persistent bleeding, and prostaglandin resistance

Uterine-preserving measures are relatively contraindicated in placental implantation disorders (placenta increta/percreta)!

References:^[6][7][8][9]