An ectopic pregnancy is defined as the implantation of the blastocyst outside the endometrial lining of the uterine cavity. Ectopic pregnancy is an important cause of maternal morbidity and mortality during the first half of pregnancy in the United States. There is an overall incidence of 2% and an incidence of 1.8% in women presenting to the emergency department (ED) with either first trimester bleeding and/or abdominal pain.5 Higher rates of mortality in adolescents are largely due to delays in seeking care. Greater than 95% of ectopic pregnancies are located in the fallopian tube.5 Risk factors include prior ectopic pregnancy, prior tubal surgery, genital tract infections leading to pelvic inflammatory disease (PID), and intrauterine device.5
Most cases present within the first 8 weeks of gestation with abdominal pain or abnormal vaginal bleeding. Pelvic or abdominal pain and exquisite tenderness are the most common complaints. Others present with a late menstrual cycle and abnormal vaginal bleeding, which can be confused with menses. In the case of a ruptured ectopic with intra-abdominal hemorrhage and hypovolemia, the clinical presentation may include dizziness and/or presyncope.6
The classically described but rare presentation of ectopic pregnancy is tenderness on abdominal examination, shock, and an adnexal mass. More commonly, the abdominal examination may be unremarkable or there may be adnexal and/or cervical motion tenderness. Laboratory and radiographic modalities that aid in the diagnosis are listed in Table 100-1.5
TABLE 100-1Diagnosis of Ectopic Pregnancy ||Download (.pdf) TABLE 100-1 Diagnosis of Ectopic Pregnancy
Urine beta-HCG: positive
Transvaginal ultrasound showing an empty uterus ± adnexal mass with a serum beta-HCG level greater than 1500–2000 mIU/mL (International Reference Preparation)
Serum progesterone: <5 ng/mL → nonviable fetus (ectopic vs. dead fetus) **
If ectopic pregnancy is suspected, consider ordering a CBC and ABORh
In an unruptured ectopic pregnancy, methotrexate, a folic acid antagonist, can be used for the medical management of an early ectopic pregnancy. Factors that favor improved success with methotrexate include hemodynamic stability without maternal hemorrhage, beta-HCG <15,000 mIU/mL, <3.5 cm gestational sac, and absence of fetal heart tones.5 Contraindications to medical management include unstable vital signs, maternal hemorrhage, tubal rupture, known liver or renal disease, or other contraindications to methotrexate; if contraindicated or not desired, then surgical management is appropriate. In a patient with a ruptured ectopic pregnancy, emergency management includes assurance of airway and breathing and cardiovascular stabilization. Rapid management of hypovolemic or hemorrhagic shock and early obstetric consultation for surgical management with transfer of care as necessary are critical.
Placenta previa is defined as a placenta that overlies or is in close proximity to the internal cervical os (Table 100-2)7 and is seen in approximately 0.3% to 0.5% of births in the United States.7 It is the primary cause of painless third trimester bleeding. Risk factors include previous cesarean delivery or uterine surgery, smoking, increased maternal age, multiparity, cocaine use, and a multiple pregnancy.7 It is thought to be caused by scarring of the endometrium.7
TABLE 100-2Classification of Placenta Previa ||Download (.pdf) TABLE 100-2 Classification of Placenta Previa
Complete: placenta completely covers internal cervical os
Partial: placenta partially covers internal os, typically only found when cervix is dilated
Marginal: edge of placenta just reaches the internal os but does not cover it
Low lying placenta: extends into the lower uterine segment but does not reach the internal os
The classic presentation of placenta previa is painless, bright red bleeding from the vagina during the late second or third trimester. The uterus usually remains soft; however, contractions may occur. Examination of the cervix may exacerbate hemorrhage with catastrophic results. Digital examination is contraindicated, and thus the use of ultrasonography is necessary to make the diagnosis. Transvaginal ultrasonography is more accurate than transabdominal ultrasonography for diagnosis but should be performed by an experienced individual with careful attention to not place the vaginal probe into the cervix. When placenta previa is diagnosed, especially in women with a history of previous cesarean delivery, placenta accreta, invasion of the previa into the myometrium, should be considered. The placenta can be evaluated by transvaginal ultrasonography or if needed by MRI for evidence of placenta accreta.
Management of known placenta previa with no acute bleeding in the ED is typically expectant and includes pelvic rest, limiting long-distance travel, and maintaining a safe hemoglobin level. Patients with hemorrhage should be stabilized with insertion of two large-bore IV catheters and given crystalloid fluids and blood transfusions, if needed. At time of delivery, cesarean delivery is required due to increased risk for hemorrhage. Delivery may ultimately lead to a hysterectomy. Thus, obstetric consultation and transfer to a facility capable of managing the mother and newly born should be initiated early as placenta previa is associated with both maternal and neonatal morbidity and mortality.7
Placental abruption is the premature separation (partial or total) of a normally implanted placenta presenting with concealed hemorrhage or vaginal bleeding. It usually occurs during the latter half of pregnancy and is seen in 1% of all pregnancies.8 It has significant perinatal mortality with 119 deaths per 1,000 pregnancies usually due to preterm delivery.8 Maternal risk factors includes previous history of placenta abruption, elevated blood pressure (due to either chronic hypertension or preeclampsia), cocaine use, cigarette smoking, multiple gestation, premature rupture of membranes, oligohydramnios, and chorioamnionitis.8 The classic presentation of placental abruption typically includes vaginal bleeding, abdominal pain, uterine tenderness, and contractions. The amount of bleeding does not correlate with the severity of abruption. In more severe cases of placental abruption, severe hemorrhage, uterine tetany, maternal hypotension, coagulopathy, fetal distress, and fetal death can be seen.8 Ultrasonography is insensitive and unreliable in the diagnosis of placental abruption; in most mild cases, the clinical diagnosis is made and confirmed postpartum on inspection of the placenta.
The management of a patient with suspected placenta abruption includes stabilizing the airway, 100% oxygen, two large-bore IV catheters, fluid resuscitation, and careful monitoring of the mother and fetus. Laboratory evaluation includes a CBC including a platelet count, coagulation studies, fibrinogen, and type and cross for matched blood.8 Early obstetric consultation and transfer to facility capable of caring for the mother and newly born must be initiated early.