A 28-year-old woman comes to the office after a positive home pregnancy test. The patient is at 5 weeks gestation by a sure, regular last menstrual period. She has had some breast tenderness but no dysuria, vaginal bleeding, or cramping. The patient has no chronic medical conditions or prior surgeries. This is her first pregnancy, and she has no history of sexually transmitted infections. Vital signs and physical examination are unremarkable. Transvaginal ultrasound shows a slightly thickened endometrial stripe but no intrauterine gestation or adnexal masses. Quantitative β-hCG is 1,100 mIU/mL and a repeat 48 hours later is 1,370 mIU/mL. The patient undergoes a diagnostic uterine dilation and curettage, and the next day β-hCG level is 1,566 mIU/mL. Which of the following is the best next step in management of this patient?

Question

A 28-year-old woman comes to the office after a positive home pregnancy test.  The patient is at 5 weeks gestation by a sure, regular last menstrual period.  She has had some breast tenderness but no dysuria, vaginal bleeding, or cramping.  The patient has no chronic medical conditions or prior surgeries.  This is her first pregnancy, and she has no history of sexually transmitted infections.  Vital signs and physical examination are unremarkable.  Transvaginal ultrasound shows a slightly thickened endometrial stripe but no intrauterine gestation or adnexal masses.  Quantitative β-hCG is 1,100 mIU/mL and a repeat 48 hours later is 1,370 mIU/mL.  The patient undergoes a diagnostic uterine dilation and curettage, and the next day β-hCG level is 1,566 mIU/mL.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

Explanation: This patient has a pregnancy of unknown location (ie, no visible intrauterine or extrauterine gestation on ultrasound), which may indicate an ectopic pregnancy or an early intrauterine pregnancy (viable or nonviable). Because over 99% of viable intrauterine pregnancies have a ≥35% rise in β-hCG levels over 48 hours, this patient's pregnancy (with β-hCG rise of only 25%) is likely an ectopic or an abnormal, nonviable intrauterine pregnancy (eg, anembryonic gestation). ectopic pregnancy To distinguish between an ectopic pregnancy and nonviable intrauterine pregnancy, patients may undergo diagnostic dilation and curettage, a procedure that samples tissue within the endometrial cavity. The procedure confirms the abnormal pregnancy's location based on the postprocedure β-hCG level: A negative or decreased β-hCG level confirms that the patient had a nonviable intrauterine pregnancy; these patients require reassurance and observation only because the products of conception have been removed by the dilation and curettage (Choice D). In contrast, a persistent rise in β-hCG level after dilation and curettage is diagnostic for an ectopic pregnancy (ie, the uterus has been evacuated but an extrauterine pregnancy continues to produce β-hCG). These patients require additional management. Methotrexate is the medical therapy for ectopic pregnancies in patients with hemodynamic stability; no renal, hepatic, or hematologic disorders (due to drug toxicity); and low β-hCG level (ie, <5000 mIU/mL). Methotrexate is a folate antagonist that inhibits DNA synthesis and cell growth preferentially in rapidly dividing cells (eg, trophoblasts). After treatment, patients require monitoring of β-hCG levels until they become undetectable to ensure that treatment is complete. (Choice A) Levonorgestrel (ie, Plan B) can be used for emergency contraception in nonpregnant women by inhibiting ovulation. It is not used for ectopic pregnancy management. (Choice C) Mifepristone (progesterone antagonist) and misoprostol (prostaglandin E1 agonist) cause uterine contractions and are used for the medical management of spontaneous abortions; they are not used to treat ectopic pregnancy. (Choice E) Higher serum progesterone levels are usually associated with normal, viable intrauterine pregnancies (and lower levels with ectopic or nonviable intrauterine pregnancies). However, levels are not diagnostic for ectopic pregnancy due to low sensitivity and specificity; therefore, measurement is not indicated. Educational objective: Ectopic pregnancy (ie, pregnancy implanted in an extrauterine location) can be diagnosed by a persistent rise in β-hCG level following diagnostic dilation and curettage. Medical therapy is with methotrexate, a folate antagonist that inhibits DNA synthesis in rapidly dividing cells (eg, trophoblasts).

A 28-Year-Old Woman Comes to the Office After a Positive