• Clinical science

Pregnancy loss

Abstract

Pregnancy loss can occur even in previously healthy pregnancies. If it occurs before 20 weeks' of gestation (∼ 10% of pregnancies), it is called early pregnancy loss, miscarriage, or spontaneous abortion. If it occurs after 20 weeks' gestation, it is called stillbirth or intrauterine fetal demise. The majority of spontaneous abortions are due to fetal aneuploidy. Other common causes of spontaneous abortion are maternal disease, trauma, and congenital anomalies. Stillbirth can be caused by maternal disease, placental disorders, umbilical cord complications, or fetal congenital anomalies. In many cases, the cause of spontaneous abortion or stillbirth is unknown. The management of pregnancy loss depends on the week of gestation and clinical presentation. Most commonly, it involves medication-induced evacuation of the pregnancy, surgical evacuation of the pregnancy, or expectant management. After a spontaneous abortion, the products of conception should undergo histopathological examination. Similarly, fetal autopsy should be performed after a stillbirth in order to determine the underlying cause and address any modifiable etiologies.

Definition

References:[1]

Etiology

Spontaneous abortion

Stillbirth

References:[2][1][3]

Clinical features

Type Findings Cervical os Prognosis
Threatened abortion
  • Vaginal bleeding
  • Fetal activity
closed reversible
Inevitable abortion
  • Vaginal bleeding, and visible/palpable products of conception
  • Fetal activity may be present.
dilated irreversible
Missed abortion
  • No bleeding
  • No expulsion of the products of conception
  • No fetal activity
closed irreversible
Incomplete abortion
  • Vaginal bleeding; products of conception within the cervical canal or uterus
  • Usually occurs > 12 weeks' gestation
dilated irreversible
Complete abortion
  • Vaginal bleeding; products of conception completely outside of the uterus
  • Usually occurs < 12 weeks' gestation
closed irreversible
Stillbirth
  • Absence of fetal movements and cardiac activity
variable irreversible

References:[1][4]

Diagnostics

Spontaneous abortion (< 20 weeks' gestation)

  • Doppler ultrasound is always used to detect fetal heart beats during prenatal visits. Absence of fetal cardiac activity should raise suspicion of spontaneous abortion.
  • Pelvic examination should be performed in all cases of vaginal bleeding. In cases of suspected spontaneous abortion, visualization of the cervix is necessary to confirm that the source of bleeding is uterine.
  • Transvaginal ultrasound is the best imaging test once there is absence of fetal cardiac activity or confirmed uterine bleeding. Findings consistent with a spontaneous abortion include:
    • Absence of fetal cardiac motion
    • Abnormalities of the yolk sac or gestational sac
  • A downtrending B-hCG is consistent with a failed pregnancy.

Stillbirth (> 20 weeks' gestation)

  • Ultrasound examination is the best diagnostic modality to confirm loss of fetal heart activity and fetal demise.
  • Fetal autopsy is recommended to ascertain the cause of death.

References:[1][3]

Treatment

Spontaneous abortion (< 20 weeks' gestation)

Prevention

  • Minimize risk with treatment of maternal disease and adequate prenatal care.

Threatened abortion

  • Expectant management (symptoms will resolve or will progress to inevitable, incomplete, or complete abortion)
  • Avoid strong physical activity
  • Weekly pelvic ultrasound
  • Rule out treatable causes of vaginal bleeding; during pregnancy (see differential diagnosis of vaginal bleeding).
  • Rh(D)-negative women should receive Rh(D)-immune globulin in cases of vaginal bleeding during pregnancy.

Inevitable, incomplete, or missed abortions

The management of uncomplicated spontaneous abortions depends mostly on patient preference. Possibilities include:

  • Expectant management (option for women < 14 weeks gestation): Surgical evacuation is usually recommended if evacuation does not occur after 4 weeks.
  • Medical evacuation: Misoprostol is used to induce cervical ripening and expulsion of the products of conception.
    • Disadvantage: more cramping and bleeding compared to surgical evacuation or expectant management
  • Surgical evacuation (dilation and curettage); : preferred method in septic abortion or if there is heavy bleeding or significant maternal disease
    • Shorter time to completion
    • Procedure:
      • Conscious sedation given → the cervix is dilated → suction evacuation → curettage (scraping) of the uterus to confirm no remaining tissue
  • Rh(D)-negative women should receive Rh(D)-immune globulin in all cases of vaginal bleeding during pregnancy.

Complete abortion

  • No treatment required
  • Confirm that the cervical os is closed and that uterus is equal or smaller in size than expected for gestational age.

Stillbirth (>20 weeks' gestation)

  • Do not rush delivery unless maternal health is at risk (i.e., preeclampsia, infection).
    • Parents need time to grieve and accept the diagnosis.
  • Spontaneous labor usually begins within 2 weeks of intrauterine fetal death. However, labor may be induced with oxytocin if maternal disease develops (e.g., coagulation abnormalities) or if the patient prefers induction.
  • Vaginal delivery is safer than cesarean section, but many patients will prefer cesarean section.
  • Express empathy and acknowledge patient grief; provide privacy and emotional support.
  • Patients should be offered a fetal autopsy to determine the cause of death.

References:[5][6][7][8]

Medical abortion

  • Definition: method for terminating unwanted pregnancy in an early stage
  • Treatment: combination of a progesterone antagonist (mifepristone) and a prostaglandin analog (e.g., misoprostol)

References:[6][9][10][11]

Complications

References:[6]

We list the most important complications. The selection is not exhaustive.