Pregnancy loss

Pregnancy loss can occur even in previously healthy pregnancies. If it occurs before 20 weeks' 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.

See also “Counseling on pregnancy loss” and “Induced abortion.”

Definition

• Spontanous abortion (early pregnancy loss, miscarriage): loss of pregnancy before 20 weeks' gestation
• Recurrent pregnancy loss: two or more pregnancy losses occurring before 20 weeks' gestation

Etiology

• Maternal
  • Abnormalities of the reproductive organs
    • Septate uterus
    • Uterine leiomyomas
    • Uterine adhesions
    • Cervical incompetence
  • Systemic diseases
    • Including diabetes mellitus, hyperthyroidism, hypothyroidism, genetic disorders, infections, hypercoagulability (e.g., antiphospholipid syndrome, which is associated with recurrent miscarriages)
• Fetoplacental
  • Chromosomal abnormalities account for up to half of all spontaneous abortions
  • Congenital anomalies
  • Anembryonic pregnancy
• Miscellaneous
  • Trauma
  • Iatrogenic (e.g., amniocentesis or chorionic villus sampling)
  • Environmental (exposure to toxins such as drugs or maternal smoking during pregnancy)
  • Unknown

Clinical features

Diagnostics

• Doppler ultrasound is always used to detect fetal heartbeats 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 β -hCG is consistent with a failed pregnancy.

Treatment

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 strenuous physical activity
• Weekly pelvic ultrasound
• Rule out treatable causes of vaginal bleeding; during pregnancy (see “Differential diagnosis of abnormal vaginal bleeding in women of reproductive age.”).
• 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.
  • When available, pretreatment with mifepristone 24 hours prior is recommended.
• Surgical evacuation (dilation and curettage)
  • Preferred method in septic abortion or if there is heavy bleeding or significant maternal disease
  • Complications include uterine perforation, hemorrhage, endometritis, and/or intrauterine adhesions ^[2]
• 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.

Complications

• Septic abortion
  • Complication of a missed, inevitable, or incomplete abortion, in which retained products of conception become infected
  • Clinical features
    • Fever
    • Abdominal and/or pelvic pain
    • Purulent vaginal discharge and/or bleeding
    • Uterine tenderness
    • Septic shock
  • Manage as any patient with sepsis
    • Broad-spectrum antibiotics
    • Surgical evacuation of uterine cavity
• Retained products of conception result in release of thromboplastin into systemic circulation → disseminated intravascular coagulation
• Endometritis

Definition

• Loss of pregnancy after 20 weeks' gestation (also called “intrauterine fetal demise”)

Etiology

• Maternal
  • Fetal-maternal hemorrhage
  • Diabetes mellitus
  • Hypertensive pregnancy disorders (especially if complicated by placental insufficiency or placental abruption)
  • Uterine rupture
  • Advanced age
  • Heavy smoking
• Fetoplacental
  • Intrauterine growth restriction (which is most commonly due to placental insufficiency)
  • Placental abnormalities (e.g., placental abruption, vasa previa)
  • Infection (especially following premature rupture of membranes)
  • Chromosomal abnormalities
  • Congenital malformations
  • Umbilical cord complications (nuchal cord or knot leading to fetal vascular compromise)
  • Fetal hydrops
• Miscellaneous
  • Unknown (in some studies, more than half of all stillbirths were of unknown etiology)
  • Environmental (exposure to toxins such as drugs or maternal smoking during pregnancy)

Clinical features

• Absence of fetal movements and cardiac activity
• Cervical os may be open or closed

Diagnostics ^[3]

• Ultrasonography confirms cessation of fetal heart activity
• The following are indicated in all cases of stillbirth to ascertain the cause of death:
  • Maternal and family history
  • Examination of the placenta, fetal membranes, and umbilical cord
  • Fetal autopsy
  • Genetic analysis (e.g., fetal karyotype)

Treatment

• Do not rush delivery unless maternal health is at risk (i.e., preeclampsia, infection).
• 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 delivery, but many patients will prefer cesarean delivery.
• Express empathy and acknowledge patient grief; provide privacy and emotional support.
• Offer contact between parents and the stillborn after delivery.
• Parents should be offered a fetal autopsy to determine the cause of death.

Complications

• Retained products of conception
• Endometritis