Medication Abortion and Uterine Aspiration for Undesired Pregnancy of Unknown Location: A Retrospective Cohort Study
Authors: Borchert Karen , Thibodeau Chelsea , Varin Paige , Wipf Heidi , Traxler Sarah , Boraas Christy M. 
Published: September 2023

Uncertain diagnosis can complicate the evaluation and treatment of patients presenting for undesired pregnancy termination at early gestational ages. Pregnant patients with no ultrasonography-identifiable pregnancy location receive classification of pregnancy of unknown location (PUL). Until receiving a definitive intrauterine pregnancy (IUP), ectopic pregnancy, or early pregnancy loss diagnosis, these patients are often managed expectantly with serial serum human chorionic gonadotropin (hCG) measurements and ultrasonography. Immediate treatment of undesired PUL with low-risk for ectopic pregnancy can be performed in ways that minimize the risk.

This retrospective cohort study reviewed outcomes of pregnancies for PUL-diagnosed patients presenting at Planned Parenthood in Minnesota, North Dakota, and South Dakota to receive induced abortions between July 1, 2016, and December 31, 2019. Care of patients with PUL included assessment of health history, counseling, and ectopic pregnancy precaution reviews. Clinicians then proceeded to triage patients into low- and high-risk groups based on transvaginal ultrasonography findings and patient symptoms. For PUL patients deemed low risk for ectopic pregnancy, the choices of expectant management or induced abortion were given. Patients proceeding with induced abortions then proceeded with uterine aspiration or medication abortion.

The primary objective compared the diagnosis of pregnancy location to time for 3 groups, which included the groups of patients choosing immediate treatment (via uterine aspiration or medical management), and the group of patients who initially chose expectant management (delay for diagnosis). Time to diagnosis, as measured in days, was recorded from initial PUL diagnosis until final pregnancy location diagnosis. A spontaneous decline of serum hCG after 48–72 hours in the delay-for-diagnosis group was recorded as a spontaneously resolved PUL consistent with spontaneous abortion. Incidence of ectopic pregnancies, complications such as transfusion-requiring hemorrhages, and failure to adhere with follow-up guidelines (greater than 60 days from PUL diagnosis without clinical contact and/or a pregnancy diagnosis) were also recorded.

From a total of 19,151 abortion counters across the study period, 2.9% of patients (553) were diagnosed with PUL. High-risk diagnoses were given to 9.4% of patients (52), based on concerns from symptoms and ultrasounds (27 of these had ectopic pregnancies [51.9%]). Low-risk diagnoses were given to 90.6% of the remaining patients (501), who were given a choice of management. When compared with expectant management, results indicated that low-risk patients with undesired PUL experienced fewer days to diagnosis with immediate treatment by uterine aspiration (and a similar time frame to diagnosis with abortion via medication). For uterine aspiration, abortion treatment using simultaneous serial hCG trending was effective. Although this study lacked statistical power to detect differences between groups, there was an overall low complication rate (0.2%).

Strengths of the study include the exclusive focus on true-PUL patients, as well as the large sample size. Generalizability was potentially increased by the fact that various physicians triaged PUL patients in the study setting without increases in complications. A weakness of the study was that even with a 60-day follow-up window, the 27% follow-up nonadherence rate was higher than the 16% of Goldberg et al. In addition, the retrospective nature of the study was also a weakness. Finally, given the inability to observe direct comparison for efficacy of delayed medication versus immediate abortion due to higher rates of spontaneous abortion in the delay-for-diagnosis group, the outcomes of the study are limited by small numbers.

This study shows that proceeding with an induced abortion in patients with PUL and undesired pregnancy are effective and safe as long as a plan for close follow-up with hCG is in place.