Abortion, Spontaneous

Essentials of Diagnosis

• Intrauterine pregnancy < 20 weeks

• Low or falling levels of human chorionic gonadotropin (hCG)

• Bleeding or midline cramping pain, or both

• Open cervical os

• Complete or partial expulsion of products of conception

General Considerations

• Defined as termination of gestation prior to the 20th week of pregnancy

• 75% of cases occur before the 16th week, with 75% of these before the 8th week

• Almost 20% of clinically recognized pregnancies terminate in spontaneous abortion

• More than 60% of cases result from chromosomal defects

• About 15% of cases are associated with

  • Maternal trauma

  • Infection

  • Dietary deficiency

  • Diabetes mellitus

  • Hypothyroidism

  • The antiphospholipid antibody syndrome

  • Anatomic malformations

  • There is no evidence that psychic stimuli such as severe fright, grief, anger, or anxiety can induce termination

• There is no evidence that electromagnetic fields are associated with an increased risk of termination

• It is important to distinguish women with incompetent cervix from more typical early abortion, premature labor, or rupture of the membranes

Demographics

• Predisposing factors

  • History of incompetent cervix

  • Cervical conization or surgery

  • Cervical injury

  • Diethylstilbestrol exposure

  • Anatomic abnormalities of the cervix

Symptoms and Signs

• Incompetent cervix

  • Classically presents as "silent" cervical dilation (without contractions) between weeks 16 and 28

• Threatened abortion

  • Bleeding or cramping without termination

  • The cervix is not dilated

• Inevitable abortion

  • The cervix is dilated and membranes may be ruptured

  • Passage of products of conception has not occurred but is considered inevitable

• Complete abortion

  • The products of conception are completely expelled

  • Pain ceases, but spotting may persist

  • Cervical os is closed

• Incomplete abortion

  • Some portion of the products of conception remains in the uterus

  • Cramps are usually mild; bleeding is persistent and often excessive

• Missed abortion

  • The pregnancy has ceased to develop, but the conception has not been expelled

  • There may be brownish vaginal discharge but no active bleeding

  • Symptoms of pregnancy disappear

Differential Diagnosis

• Ectopic pregnancy

• Hydatidiform mole

• Incompetent cervix

• Anovular bleeding in a nonpregnant women

• Menses or menorrhagia

• Cervical neoplasm or lesion

Laboratory Tests

• Falling levels of hCG

• Complete blood count should be obtained if bleeding is heavy

• Rh type should be determined and Rho(D) Ig given if the type is Rh negative

• All recovered tissue should be preserved and assessed by a pathologist

Imaging Studies

• Transvaginal ultrasound can identify the gestational sac 5–6 weeks from the last menstrual period, a fetal pole at 6 weeks, and fetal cardiac activity at 6–7 weeks

• Diagnostic criteria of early pregnancy loss

  • Crown-rump length of 7 mm or more and no heartbeat

  • Mean sac diameter of 25 mm or more and no embryo

Medications

• Antibiotics should be used only if there is evidence of infection

• Data are lacking to support the administration of progestins to all women with a threatened abortion

• If an infection is diagnosed (ie, urinary tract infection), it should be treated

• Medically induced first trimester termination with prostaglandins

  • Misoprostol, 200–800 mcg orally or vaginally once is safe, effective, less invasive, and more private than surgical intervention

  • If unsuccessful or if there is excessive bleeding, a surgical procedure may be needed

Surgery

• Inevitable or incomplete or abortion is treated with prompt removal of any remaining products of conception to stop bleeding and prevent infection

Therapeutic Procedures

• Threatened abortion

  • Bed rest for 24–48 hours followed by gradual resumption of usual activities has been offered in the past, no benefit has been seen in studies

  • Abstinence from sexual activity has also been suggested without proven benefit

• Inevitable or missed abortion

  • If medically induced first-trimester termination with prostaglandins (ie, misoprostol) is unsuccessful or if there is excessive bleeding, a surgical procedure (dilation and curettage) may still be needed

• Incompetent cervix

  • Treated with cerclage and restriction of activities

  • Testing for Neisseria gonorrhoeae, Chlamydia trachomatis, and group B streptococci should be obtained before the procedure

Follow-Up

• With recurrent first-trimester losses (three or more) chromosomal analysis of tissue may be informative

Complications

• Retained tissue and prolonged bleeding can occur with prostaglandin use

When to Refer

• Patient with history of two second-trimester losses

• Vaginal bleeding in a pregnant patient that resembles menstruation

• Patient with an open cervical os

• No signs of uterine growth in serial examinations of a pregnant patient

• Leakage of amniotic fluid

When to Admit

• Open cervical os

• Heavy vaginal bleeding

• Leakage of amniotic fluid