INTRODUCTION

Section 2 of 11  

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Background

An ectopic pregnancy occurs when a fertilized ovum implants at a site other than the endometrial lining of the uterus. Ectopic pregnancies occur in the fallopian tube in 97% of cases, with 55% in the ampulla; 25% in the isthmus; 17% in the fimbria; and 3% of cases within the abdomen, ovary, and cervix.

Pathophysiology

Ectopic pregnancies are primarily due to prior tubal/genital infection or surgery, fallopian anatomic abnormalities, or endometrial abnormalities. Abnormal implantation sites include the fallopian tube, interstitium (formerly cornu), ovary, cervix, and peritoneum.

Frequency

United States

The incidence of ectopic pregnancy in 1992 based on aggregated inpatient and outpatient data was 108,800, or 19.7 per 1000 reported pregnancies. Females taking fertility drugs have a higher risk of ectopic pregnancy than that of females not taking such drugs.

Mortality/Morbidity

• Ectopic pregnancy is the leading cause of pregnancy-related death in the first trimester, and it is a cause of significant morbidity. It is responsible for 10% of maternal deaths.
• Surveillance data for pregnancy-related deaths in the United States for 1987-1990 revealed 1,459 deaths. Ectopic pregnancy accounted for 10.8% of these deaths.

Race

African American teenagers and teenagers of other minority races have a mortality rate that was almost 5 times higher than that of white teenagers.

Age

Most ectopic pregnancies occur in women aged 25-34 years.

• Surveillance data of pregnancy-related deaths (from all causes) in 1987-1990 demonstrated that women aged 30 years or older had a higher risk for pregnancy related death than that of younger women.
• Women aged 35-39 years had a 2.6-fold higher risk for death than that of women aged 25-29 years; the risk was 5.9-fold higher for women aged 40 years or older.

CLINICAL

Section 3 of 11  

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History

The history of patients with an ectopic pregnancy may include the following features:

• History of late or delayed menses
• Abdominal and/or pelvic pain and cramping
• Vaginal bleeding (may be absent)
• Shoulder pain
• Faintness
• Marked or painful fetal movements

Physical

Physical examination is unreliable for clinicians who face this significant diagnostic challenge. Abbott et al and Stovall et al reported an alarming rate of missed and/or delayed diagnoses in the ED. Although findings at physical examination may be variable, they may include the following:

• Vaginal bleeding may be mild or absent. Up to 30% of patients with ectopic pregnancies have no vaginal bleeding.
• Abdominal pain may be minimal or severe.
• Shoulder pain is suggestive of peritoneal free fluid (significant hemorrhage).
• Ectopic pregnancies can be accompanied by sloughing material, which is suggestive of a miscarriage.
• Adnexal masses may be palpable in only 60% of patients (under anesthesia).
• Tenesmus or syncope may occur.
• Decidual cast may be passed.
• Clinical shock may occur after rupture.
• No combination of physical findings may reliably exclude the diagnosis of ectopic pregnancy.

Causes

Causes of ectopic pregnancy may include the following:

• Previous tubal pregnancy or surgery
• Pelvic inflammatory disease (PID)
• Endometriosis
• Salpingitis isthmica nodosa
• Pelvic adhesions
• Pelvic tumors
• Atrophic endometrium
• Septate uterus
• Presence of an intrauterine device (IUD)
• Oral contraceptive use

DIFFERENTIALS

Section 4 of 11  

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Other Problems to be Considered

Abortion, postabortion bleeding
Abortion, retained products
Ruptured corpus luteum cyst
Cornual myoma or abscess
Ovarian tumor
Endometrioma
Cervical cancer
Cervical phase of uterine abortion

WORKUP

Section 5 of 11  

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Lab Studies

• Human chorionic gonadotropin (HCG) levels may be analyzed quantitatively.
• • The quantitative level of beta-HCG varies in ectopic pregnancy; low levels of beta-HCG can occur.
  • Serum beta-HCG levels correlate with the size and gestational age in normal embryonic growth.
  • The discriminatory zone of beta-HCG levels is the level above which a normal intrauterine pregnancy reliably is visualized.
  • The absence of an intrauterine pregnancy when the HCG level is above the level in the discriminatory zone represents an ectopic pregnancy or a recent abortion.
• Serial blood cell counts should be determined to quantify blood loss.
• A serum progesterone level may be useful in identifying patients with a miscarriage.
• The serum creatine kinase level has been proposed as a marker of ectopic pregnancy.

Imaging Studies

• The use of bedside ultrasonography in the ED is fast, feasible, and accurate; it is associated with improved patient outcome. Endovaginal ultrasonography may be used at the bedside to rule-in an intrauterine pregnancy.
• • A definite intrauterine pregnancy is present when a gestational sac with a sonolucent center (>5 mm in diameter) is surrounded by a thick, concentric, echogenic ring located within the endometrium and contains a fetal pole, yolk sac, or both.
  • A probable abnormal intrauterine pregnancy occurs when a gestational sac larger than 10 mm in diameter is present without a fetal pole or when a definite fetal pole is present without cardiac activity.
  • A definite ectopic pregnancy is characterized by the presence of a thick, brightly echogenic, ringlike structure outside the uterus, with a gestational sac containing an obvious fetal pole, yolk sac, or both.
  • Pregnancy of unknown location occurs with an empty uterus on endovaginal sonograms in patients with serum beta-HCG levels greater than the discriminatory cutoff value. In this case, an ectopic pregnancy is considered present until proven otherwise. An empty uterus may also represent a recent abortion.
  • Other ultrasonographic findings include an adnexal mass, free cul-de-sac fluid, and/or severe adnexal tenderness upon palpation with the probe. Patients with no definite intrauterine pregnancy and the aforementioned findings are thought to have a high risk for ectopic pregnancy.
• An appreciation for the spectrum of ultrasonographic findings in ectopic pregnancy may enable recognition of an early ectopic pregnancy. Findings include the following:
• • Tubal ring: This is an echogenic ringlike structure outside of the uterus. This finding represents an early ectopic pregnancy.
  • Extrauterine mass: The presence of a tender adnexal mass at ultrasonography suggests an ectopic pregnancy. The findings of one study suggest that the presence of any adnexal mass other than a simple cyst is the most significant ultrasonographic finding in the diagnosis of ectopic pregnancy.
  • Interstitial ectopic pregnancy: An interstitial ectopic pregnancy is one that implants at the highly vascular region of the uterus near the insertion of the fallopian tube. These types can grow larger than can those within the fallopian tube because the endometrial tissue is more expandable. Because of the increased size and partial endometrial implantation, these advanced ectopic pregnancies can be misdiagnosed as an intrauterine pregnancy. A clue to the diagnosis of an interstitial ectopic pregnancy is the eccentric location of the gestational sac. It is important to evaluate the amount of uterine myometrium surrounding the gestational sac and echogenic decidual layer. This thickness is called the myometrial mantle. At least 5 mm of myometrium should be present. A finding of less than 5 mm suggests the diagnosis. Another sonographic finding is the interstitial line sign.
  • Heterotopic pregnancy: This is a combined intrauterine and ectopic pregnancy. It is thought to occur in approximately 1 in 3000 pregnancies and is more common in patients taking fertility agents.
  • Extrauterine empty gestational sac: The presence of an extrauterine mass with a thick brightly echogenic band (rind) may represent an ectopic pregnancy.
  • Hemosalpinx: The fallopian tubes may fill with blood or free fluid. One study found hematosalpinx as pathognomonic of ectopic pregnancy.
  • Ruptured ectopic pregnancy: Findings on sonograms include free fluid or clotted blood in the cul-de-sac or intraperitoneal gutters, such as the Morison pouch.

Procedures

• Culdocentesis can be performed to diagnose fluid in the cul-de-sac; however, ultrasonography is relatively noninvasive and is sensitive for cul-de-sac fluid.
• Endometrial biopsy may be performed.
• Dilatation and curettage may be performed.

TREATMENT

Section 6 of 11  

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Prehospital Care

Patients in shock require prehospital care to treat hypotension.

Emergency Department Care

• Endovaginal ultrasonography can be performed rapidly at the patient's bedside to identify a definite intrauterine pregnancy.
• Many protocols are used for patients with possible ectopic pregnancy; however, early endovaginal ultrasonography permits a rapid identification and treatment of patients with vaginal bleeding, abdominal pain, or risk factors for ectopic pregnancy.
• Laparotomy is required for ovarian, abdominal, and intraligamentous pregnancy.
• Careful curettage, packing of the cervix and uterine cavity, bilateral internal iliac artery ligation, or even hysterectomy may be required for a cervical pregnancy.
• An unruptured tubal pregnancy of less than 4 mm in diameter may be treated by salpingostomy by means of laparoscopy.

Consultations

An obstetrician routinely should be consulted to streamline patient care in the ED and to perform outpatient follow-up for patients who requiring it.

MEDICATION

Section 7 of 11  

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The goal of therapy is to prevent complications.

Drug Category: Anti-Metabolite

These agents are used to terminate pregnancy.

FOLLOW-UP

Section 8 of 11  

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Further Outpatient Care

• Patients with no definite intrauterine pregnancy, no significant incidental findings on endovaginal sonograms, or very low beta-HCG levels, should undergo follow-up with an obstetrician/gynecologist, and preclinical beta-HCG levels should be determined within 2-3 days.

Transfer

• Patients who have a definite ectopic pregnancy, as depicted on sonograms; those with free fluid; and those with a suspicious extrauterine mass should undergo emergency laparoscopy or laparotomy.
• If these services are unavailable, such as in the case of a freestanding facility, the patient should be transferred to a facility that provides a higher level of care.

Deterrence/Prevention

• Reliable contraception may help prevent ectopic pregnancy.

Complications

• When performing sonography for the diagnosis of ectopic pregnancy, the following potential diagnostic pitfalls should be considered:
• • Low beta-HCG levels: Beta-HCG levels must be considered carefully in conjunction with ultrasonographic findings. Low beta-HCG levels may be misleading. Kaplan et al found that 29% of ectopic pregnancies with beta-HCG levels less than 1000 were ruptured. Indeterminate sonographic findings in pregnant patients should prompt further workup despite beta-HCG levels.
  • Location of the gestational sac: An ectopic pregnancy may be mistaken for a hemorrhagic corpus luteal cyst or bowel. Advanced ectopic pregnancies are misdiagnosed as intrauterine pregnancies when the gestational sac and contents have a normal appearance but when the sonographer overlooks the extrauterine position of the sac. A systematic approach using the longitudinal and transverse imaging planes of the uterus and adnexa is mandatory. The ultrasonographic examination in not complete when an intrauterine pregnancy is identified.
  • Pseudogestational sac: A pseudogestational sac can be confused with a gestational sac or embryonic demise. An ectopic pregnancy may stimulate the endometrium, causing fluid collection within the endometrium.
• Hemorrhage and hypovolemic shock
• Infection
• Loss of reproductive organs following surgery
• Infertility
• Urinary and/or intestinal fistulas following complicated surgery
• Disseminated intravascular coagulation

Prognosis

• The prognosis with an ectopic pregnancy is good for patients with an early diagnosis.
• Fertility may be preserved in patients with an early ectopic pregnancy, such as those with a tubal ring.

Patient Education

• Patients with a previous ectopic pregnancy should be educated regarding the potential increased risk for another ectopic pregnancy.
• Patients taking fertility drugs should also be aware of the increased risk of ectopic pregnancy.
• For excellent patient education resources, visit eMedicine's Pregnancy and Reproduction Center. Also, see eMedicine's patient education articles Miscarriage, Ectopic Pregnancy, Abortion, Dilation and Curettage (D&C), Birth Control Overview, and Birth Control FAQs.

MISCELLANEOUS

Section 9 of 11  

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Medical/Legal Pitfalls

• Failure to properly diagnose an ectopic pregnancy

MULTIMEDIA

Section 10 of 11  

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• Multimedia
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Media file 1:  Pregnancy, ectopic. An endovaginal sonogram reveals an intrauterine pregnancy at approximately 6 weeks. A yolk sac (ys), gestational sac (gs), and fetal pole (fp) are depicted.
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Media type:  Image

Media file 2:  An endovaginal sonogram demonstrates an early ectopic pregnancy. An echogenic ring (tubal ring) found outside of the uterus can be seen in this view.
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Media type:  Image

Media file 3:  An endovaginal sonogram reveals a complex mass outside of the uterus with a small yolk sac present within. The mass is more echogenic than the uterus above it and represents an ectopic pregnancy.
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Media type:  Image

Media file 4:  A pseudogestational sac of an ectopic pregnancy can be confused with embryonic demise. A pseudogestational sac is produced when an ectopic pregnancy stimulates the endometrium, with degeneration of the central decidual reaction.
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Media type:  Ultrasound

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Clinical
• Differentials
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Article Last Updated: Jun 8, 2006