Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 19-08: Spontaneous Abortion + Key Features Download Section PDF Listen +++ +++ 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 + Clinical Findings Download Section PDF Listen +++ +++ 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 + Diagnosis Download Section PDF Listen +++ +++ 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 + Treatment Download Section PDF Listen +++ +++ 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 + Outcome Download Section PDF Listen +++ +++ 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 + References Download Section PDF Listen +++ + +American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 142: Cerclage for the management of cervical insufficiency. Obstet Gynecol. 2014 Feb; 123(2 Pt 1):372–9. [Reaffirmed 2016] [PubMed: 24451674] + +American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 200: Early pregnancy loss. Obstet Gynecol. 2018 Nov;132(5):e197–207. [PubMed: 30157093]