Threatened Abortion and Spontaneous Abortion Case File

Threatened Abortion and Spontaneous Abortion Case File

Eugene C. Toy, MD, Patti Jayne Ross, MD, Benton Baker III, MD, John C. Jennings, MD

CASE 42

Scenario 1: An 18-year-old G1P0 female, who is pregnant at 7 weeks’ gestation by last menstrual period (LMP), complains of a 2-day history of vaginal spotting and lower abdominal pain. Her blood pressure (BP) is 130/60 mm Hg, heart rate (HR) is 70 beats per minute, and temperature is 99°F (37.2°C). The abdomen is nontender and without masses. On pelvic examination, the uterus is 4-week size and nontender, and there are no adnexal masses. The cervix is closed. The serum beta-human chorionic gonadotropin (β-hCG) level is 700 mIU/mL and a transvaginal ultrasound reveals an empty uterus and no adnexal masses.

» What is your next step in the management of this patient?

Scenario 2: A 35-year-old woman at 8 weeks’ gestation complains of crampy lower abdominal pain and vaginal bleeding. She states that the pain was intense last night, and that something that looked like liver passed per vagina. After that, the pain subsided tremendously as did the vaginal bleeding. Her blood pressure (BP) is 130/80 mm Hg, heart rate (HR) is 90 beats per minute, and temperature is 98°F (36.6°C). Her abdominal examination is unremarkable. The pelvic examination reveals normal external female genitalia. The cervix is closed and nontender.

» What is the most likely diagnosis?

» What is your next step in management?

ANSWER TO CASE 42:

Threatened Abortion and Spontaneous Abortion                                   

Summary of Scenario 1: An 18-year-old adolescent female at 7 weeks’ gestation by LMP complains of a 2-day history of vaginal spotting and lower abdominal pain. The physical examination reveals a 4-week-sized uterus and unremarkable adnexa. The β-hCG level is 700 mIU/mL and no intrauterine gestational sac is noted on endovaginal sonography.

• Next step in management: Follow-up β-hCG level in 48 hours.

Summary of Scenario 2: A 35-year-old woman at 8 weeks’ gestational age had intense crampy lower abdominal pain and vaginal bleeding last night; after passing what looked like “liver,” her pain and bleeding subsided tremendously. On examination, her cervix is closed.

• Most likely diagnosis: Completed abortion.
• Next step in management: Follow hCG levels to zero.

ANALYSIS

Objectives

1. Understand the concept of the hCG discriminatory zone or threshold, and its utility with transvaginal sonography.
2. Understand the principle of obtaining a follow-up hCG level when a patient is asymptomatic and has an hCG level that is below the discriminatory zone.
3. Know that a normal ultrasound examination does not rule out the presence of an ectopic pregnancy.
4. Know the typical characteristics of the different types of spontaneous abortions.
5. Understand the clinical presentations of and the treatments for the different types of abortions.

Considerations

In scenario 1, this 18-year-old patient complains of lower abdominal pain and vaginal spotting. Although there are numerous possible causes, the priority should be to assess for possible pregnancy and especially possible ectopic pregnancy. She does not have a history of sexually transmitted diseases, which if present would be a risk factor for an ectopic pregnancy. The physical examination is unremarkable and ultrasound does not show any adnexal masses. Of note, the hCG level is below the threshold whereby transvaginal sonography should reveal an intrauterine pregnancy (IUP; hCG threshold of 1500-2000 mIU/ mL). Thus, the next step in management is to determine whether this pregnancy is a normal intrauterine gestation or an abnormal pregnancy. This may be accomplished by following serial hCG levels. In a normal intrauterine pregnancy, if the follow-up hCG level at 48 hours rises by at least 66%, then the patient most likely has a normal intrauterine pregnancy. If the follow-up hCG does not rise by 66% (particularly, if it rises by only 20%), then she most likely has an abnormal pregnancy. A subnormal rise in hCG does not indicate whether the abnormal pregnancy is in the uterus or the tube. The gestational age based on last menstrual period is not very reliable. Thus, the hCG levels and transvaginal ultrasound are generally the best tools for evaluating a possible ectopic pregnancy.

In scenario 2, the patient is pregnant at 8 weeks’ gestation, which is in the first trimester. She noted intense cramping pain the night before and passed something that looked like liver to her. This may be tissue, although the gross appearance of presumed tissue can be misleading. The patient’s pain and bleeding have subsided since the passage of the “liver.” This is consistent with the complete expulsion of the pregnancy tissue. The clinical picture of passage of tissue, resolution of cramping and bleeding, and a closed cervical os are consistent with a completed abortion. To confirm that all of the pregnancy (trophoblastic) tissue has been expelled from the uterus, the clinician should follow serum quantitative hCG levels. It is expected that the hCG levels should halve every 48 to 72 hours. If the hCG levels plateau instead of falling, then the patient has residual pregnancy tissue (which may be either an incomplete abortion or an ectopic pregnancy). Notably, this patient is of advanced maternal age, and spontaneous abortions are more common in older patients. The most common cause identified with spontaneous abortion is a chromosomal abnormality of the embryo.

APPROACH TO:

Threatened Abortion and Spontaneous Abortion                                         

DEFINITIONS

THREATENED ABORTION: Pregnancy with vaginal spotting during the first half of pregnancy. This does not delineate the viability of the pregnancy.

ECTOPIC PREGNANCY: Pregnancy outside of the normal uterine implantation site. Most of the time, this means a pregnancy in the fallopian tube.

HUMAN CHORIONIC GONADOTROPIN: “The pregnancy hormone,” which is a glycoprotein that is secreted by the chorionic villi of a pregnancy. It is the hormone on which pregnancy tests are based. The normal pregnancy will have a logarithmic rise in early pregnancy.

hCG THRESHOLD: Level of serum hCG such that an intrauterine pregnancy should be seen on ultrasound. For endovaginal sonography, this level is 1500 to 2000 mIU/mL. When an intrauterine pregnancy is not seen on sonography and the hCG level exceeds the threshold, then it is highly probable that an ectopic pregnancy is present.

INEVITABLE ABORTION: A pregnancy <20 weeks’ gestation associated with cramping, bleeding, and cervical dilation; there is no passage of tissue.

INCOMPLETE ABORTION: A pregnancy <20 weeks’ gestation associated with cramping, vaginal bleeding, an open cervical os, and some passage of tissue per vagina, but also some retained tissue in utero. The cervix remains open due to the continued uterine contractions; the uterus continues to contract in an effort to expel the retained tissue.

COMPLETED ABORTION: A pregnancy <20 weeks’ gestation in which all the products of conception have passed; the cervix is generally closed. Because all the tissue has passed, the uterus no longer contracts, and the cervix closes.

MISSED ABORTION: A pregnancy < 20 weeks’ gestation with embryonic or fetal demise but no symptoms such as bleeding or cramping.

CLINICAL APPROACH

Threatened Abortion

When a pregnant woman <20 weeks’ gestation has vaginal bleeding, it is described as threatened abortion. The more difficult assessment is in the first 6 to 7 weeks of gestation when the status of the pregnancy and location of the pregnancy are uncertain. The gestational age based on LMP of patients with threatened abortion is unreliable due to the irregular bleeding. In general, patients with threatened abortion fall into three possible etiologies:

• Viable intrauterine pregnancy (about 50%)—bleeding will abate and pregnancy will continue
• Spontaneous abortion (nonviable IUP—about 35%)—the bleeding indicates a nonviable intrauterine pregnancy
• Ectopic pregnancy (nonviable pregnancy in tube; about 15%)

Of the three possibilities, ectopic pregnancy is the most dangerous; thus, the strategy in assessing threatened abortion or pregnant women with abdominal pain is to evaluate for possible ectopic pregnancy. It is of paramount importance to determine if the woman is hypotensive, volume depleted, or has severe abdominal or adnexal pain. These patients will most likely need laparoscopy or laparotomy since ectopic pregnancy is probable. For asymptomatic women, the quantitative

human chorionic gonadotropin level is useful. When the hCG level is below the threshold for sonographic visualization of an intrauterine gestational sac, then repeat hCG level is generally performed in 48 hours to establish the viability of pregnancy. Another option would be a single progesterone level: levels > 25 ng/ mL almost always indicate a normal intrauterine gestation, whereas values < 5 ng/ mL usually correlate with a nonviable gestation. When a nonviable pregnancy is diagnosed either by an abnormal hCG rise or single progesterone assay (<5 ng/mL), it is still unclear whether the patient has a spontaneous abortion or an ectopic pregnancy. Many clinicians will perform a uterine curettage at this time to assess whether the patient has a miscarriage (histologic confirmation of chorionic villi) or an ectopic pregnancy (no villi from the curettage). Women with asymptomatic, small (< 3.5 cm) ectopic pregnancies are ideal candidates for intramuscular methotrexate. A nonviable intrauterine pregnancy may be managed expectantly, surgically via dilation and curettage, or medically with vaginal misoprostol. Vaginal misoprostol has been reported to be effective in evacuating the pregnancy in about 80% of cases.

When the hCG level is greater than the ultrasound threshold, a transvaginal sonogram will dictate the next step. A patient in whom an intrauterine gestational sac is seen may be sent home with a diagnosis of threatened abortion and should have close follow-up. There is still a significant risk of miscarriage. When the hCG level is above the threshold, and there is no sonographic evidence of intrauterine pregnancy, the risk of ectopic pregnancy is high (about 85%), and thus laparoscopy is often undertaken to diagnose and treat the ectopic pregnancy. Because an intrauterine gestation is possible in this circumstance (about 15% of the time), methotrexate is usually not given; however, a high hCG level in the face of a sonographically empty uterus is almost always caused by an extrauterine gestation (see Figure 42– 1 for one example of a management scheme). Finally, Rh-negative women with threatened abortion, spontaneous abortion, or ectopic pregnancy should receive RhoGAM to prevent isoimmunization.

Spontaneous Abortion

When the pregnancy is so early that a gestational sac is not able to be seen on ultrasound, then the status of the pregnancy is unsure. However, if the gestational sac or embryo is seen, or the patient presents with passage of tissue, then spontaneous abortion can be diagnosed. The history, physical examination, and/ or sonography usually point to the category of spontaneous abortion (Table 42– 1). Women with symptoms of spontaneous abortion should be instructed to bring in any passed tissue for histologic analysis.

Note: An inevitable abortion must be differentiated from an incompetent cervix. With an inevitable abortion, the uterine contractions (cramping) lead to the cervical dilation. With an insufficient cervix, the cervix opens spontaneously without uterine contractions and, therefore, affected women present with painless cervical dilation, usually in the second trimester. This disorder is treated with a surgical ligature at the level of the internal cervical os (cerclage). Hence, one of the main features used to distinguish between an insufficient cervix and an inevitable abortion is the presence or absence of uterine contractions.

The treatment of a missed or incomplete abortion includes expectant management for passage of tissue, medical management with mifepristone and misoprostol (misoprostol alone), and surgical management with dilatation and curettage of the uterus for immediate, definitive treatment. The primary complications of persistently retained tissue are bleeding and infection. A completed abortion is suspected by the history of having passed tissue and experiencing cramping abdominal pain, now resolved. The cervix is closed. Serum hCG levels are still followed to confirm that no further chorionic villi are contained in the uterus.

Figure 42–1. Algorithm for management of threatened abortion.

Differential Diagnosis

A pregnant patient who presents with abdominal pain and vaginal pain has a threatened abortion. The differential diagnosis includes: viable IUP, nonviable IUP, ectopic pregnancy, cervical or vaginal lesions/ laceration, and more rarely molar pregnancy.

Molar Pregnancy

An unusual type of abnormal pregnancy is a molar pregnancy (incidence 1:1200 pregnancies), which is trophoblastic tissue, or placenta-like tissue, usually without a fetus. The clinical presentation of molar pregnancy is vaginal spotting, absence of fetal heart tones, size greater than dates, and markedly elevated hCG levels. The diagnosis is by ultrasound, revealing a “snow storm”-like pattern in the uterus. Uterine suction curettage is the treatment. After curettage, patients are followed with weekly hCG levels because sometimes gestational trophoblastic disease persists after evacuation of the molar pregnancy. In these instances, chemotherapy is used.

CASE CORRELATION See also Case 43 (Ectopic Pregnancy). A patient with a threatened abortion may have a viable intrauterine pregnancy, a spontaneous abortion, or an ectopic pregnancy.

COMPREHENSION QUESTIONS

Match the single best treatment (A-E) with the clinical scenario (42.1-42.4).

A. Laparoscopy

B. Follow-up hCG level in 48 hours

C. Cervical cerclage

D. Dilation and curettage of uterus

E. Expectant management

42.1 A 19-year-old G1P0 woman at 18 weeks’ gestation, who had a prior cervical conization procedure, states that she has felt no abdominal cramping. She has a cervical dilation of 2 cm and effacement of 70%.

42.2 A 33-year-old woman at 10 weeks’ gestation complains of vaginal bleeding and passage of a whitish substance along with something “meat-like.” She continues to have cramping, and her cervix is 2 cm dilated.

42.3 A 20-year-old G2P1 woman at 12 weeks’ gestation has had no problems with this pregnancy prior to today. She complains of some slight vaginal spotting. No fetal heart tones are heard on Doppler, and a transvaginal ultrasound reveals no uterine gestational sac and no adnexal masses. The hCG level is 700 mIU/mL.

42.4 A 28-year-old G3P2 woman at 22 weeks’ gestation is noted to have vaginal spotting, and fetal heart tones are in the range of 140 to 145 bpm.

42.5 An 18-year-old adolescent female who is brought to the emergency room complains of vaginal spotting and lower abdominal pain. Her abdominal and pelvic examinations are normal. The hCG level is 700 mIU/mL and transvaginal sonogram shows no intrauterine gestational sac and no adnexal masses. Which of the following statements is most accurate regarding this patient’s situation?

A. She has an unruptured ectopic pregnancy.

B. She has a viable intrauterine pregnancy that is too early to assess on ultrasound.

C. She has a nonviable intrauterine pregnancy.

D. There is insufficient information to draw a conclusion about the viability of this pregnancy.

E. A magnetic resonance imaging (MRI) scan would be useful in further assessing the possibility of an ectopic pregnancy.

42.6 A 22-year-old woman, who is pregnant at 5 weeks’ gestation, complains of severe lower abdominal pain. On examination, she is noted to have a blood pressure of 86/ 44 mm Hg and heart rate of 120 bpm. Her abdomen is tender. The pelvic examination is difficult to perform due to guarding. The hCG level is 500 mIU/ mL and the transvaginal sonogram reveals no intrauterine gestational sac and no adnexal masses. There is some free fluid in the cul-de-sac. Which of the following is the best management for this patient?

A. Repeat hCG level in 48 hours to assess for a rise of 66%

B. Check the serum progesterone level

C. Immediate surgery

D. Intramuscular methotrexate

E. Repeat sonography in 48 hours

ANSWERS

42.1 C. The hallmark of cervical insufficiency is painless dilation of the cervix. Cervical conization is a risk factor for an insufficient cervix. Other risk factors for incompetent cervix include: congenital manifestations (ie, short cervix or collagen disorder), trauma to the cervix, prolonged second stage of labor, and uterine overdistention as with a multiple gestation pregnancy. No contractions were felt by the patient in this scenario, so the diagnosis is less likely to be inevitable abortion. Cervical insufficiency may be treated with a surgical ligature known as a cerclage.

42.2 D. An open cervical os, a history of passing tissue, and continued cramping are all findings consistent with an incomplete abortion. If the cramping had stopped and the cervix closed, this would have been a complete abortion. The treatment of an incomplete abortion is dilation and curettage (D&C) of the uterus to prevent complications of retained tissue such as hemorrhage and infection. The products of conception obtained from the curettage are sent for pathology to confirm the diagnosis and to look for rare complications such as molar pregnancy.

42.3 B. This patient has a threatened abortion. Her hCG level is below the threshold when a gestational sac should be seen on transvaginal sonography (1500-2000 mIU/mL). Thus, it is unclear with the information at this time to discern whether she has a normal early intrauterine pregnancy, or an abnormal pregnancy (miscarriage or ectopic). Follow-up hCG level in 48 hours would be judicious; an appropriate rise in hCG of at least 66% is consistent with a normal intrauterine pregnancy, whereas a rise < 66% is highly suggestive of an abnormal pregnancy.

42.4 E. This patient does not have an abortive process since she is at 22 weeks’ gestation; she has antepartum bleeding. Abortions are described as <20 weeks’ gestation. The two most common causes of antepartum bleeding are placenta previa and placental abruption. In abruption, the patient typically presents to triage with severe abdominal pain. The evaluation of this patient would include ultrasound to assess for placenta previa, and if this is ruled out, then speculum examination and assessment for abruption.

42.5 D. There is insufficient information in this scenario to establish viability of the pregnancy. A repeat hCG in 48 hours may be able to assess the state of the pregnancy. Since no conclusion may be drawn, it would be difficult to say whether this patient has an unruptured ectopic pregnancy, an intrauterine pregnancy that is too early to assess by ultrasound, or a nonviable intrauterine pregnancy. An MRI is not specific in evaluating for an ectopic versus viable intrauterine pregnancy; plus, it is costly and time consuming.

42.6 C. Surgery is indicated because this patient is hypotensive and tachycardic due to a likely ruptured ectopic pregnancy. This patient is in shock, and immediate surgery is indicated to prevent end-organ damage that may immediately lead to or eventually result in death. Delaying treatment or relying on intramuscular (IM) methotrexate is not indicated for a patient in hemodynamic instability. Considering the patient’s symptoms, methotrexate would be an ineffective treatment anyway since the ectopic pregnancy has most likely ruptured. A progesterone level would not be of use because tubal rupture in itself would indicate a nonviable gestation was present.

    CLINICAL PEARLS    

» Women with threatened abortion may have a viable IUP, a spontaneous abortion, or an ectopic pregnancy. » When the hCG level is above the threshold and no intrauterine pregnancy is seen on transvaginal ultrasound, the patient most likely has an ectopic pregnancy. » Early in the course of a normal intrauterine pregnancy, the β-hCG should rise by at least 66% over 48 hours. » The presence of a true intrauterine gestational sac on ultrasound makes the risk of ectopic pregnancy very unlikely. » Surgery is usually the best therapy in a patient with an early pregnancy who is hypotensive or has severe adnexal pain. » When a pregnant woman has an open cervical os with uterine cramping and history of passage of tissue, she usually has an incomplete abortion, best treated by uterine curettage. » The typical history of a completed abortion is resolution of cramping and vaginal bleeding following passage of tissue, and the finding of a small firm uterus and a closed cervical os. » The most common cause of a first-trimester miscarriage is a fetal karyotypic abnormality. » Cervical insufficiency, which is suspected with painless cervical dilation, is best treated with a cervical cerclage (ligature). » A molar pregnancy is an unusual type of pregnancy characterized by vaginal spotting, absence of fetal heart tones, and size greater than dates. The diagnosis is made by sonography.

REFERENCES

American College of Obstetricians and Gynecologists. Medical management of ectopic pregnancy. ACOG Practice Bulletin 94. Washington, DC; 2008. 

American College of Obstetricians and Gynecologists. Diagnosis and treatment of gestational trophoblastic disease. ACOG Practice Bulletin 53. Washington, DC; 2004. 

American College of Obstetricians and Gynecologists. Medical management of abortion. ACOG Practice Bulletin 67. Washington, DC; 2005. 

American College of Obstetricians and Gynecologists. Medical management of ectopic pregnancy. ACOG Practice Bulletin 94. Washington, DC; 2010. 

Katz VL. Recurrent and spontaneous abortion. In: Katz VL, Lentz GM, Lobo RA, Gersenson DM, eds. Comprehensive Gynecology. 5th ed. St. Louis, MO: Mosby-Year Book; 2007:359-388. 

Lobo RA. Ectopic pregnancy. In: Katz VL, Lentz GM, Lobo RA, Gersenson DM, eds. Comprehensive Gynecology. 5th ed. St. Louis, MO: Mosby-Year Book; 2007:389-410. 

Lu MC, Williams III J, Hobel CJ. Antepartum care: preconception and prenatal care, genetic evaluation and teratology, and antenatal fetal assessment. In: H acker NF, Gambone JC, Hobel CJ, eds. Essentials of Obstetrics and Gynecology. 5th ed. Philadelphia, PA: Saunders; 2009:71-90. 

Shamonki M, Nelson AL, Gambone JC. Ectopic pregnancy. In: H acker NF, Gambone JC, Hobel CJ, eds. Essentials of Obstetrics and Gynecology. 5th ed. Philadelphia, PA: Saunders; 2009:290-297. 

Z hang J. A comparison of medical management with misoprostol and surgical management of early pregnancy failure. N Eng J Med. 2005;253(8):761-769.

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