Medication abortion and uterine aspiration for undesired pregnancy of unknown location: A retrospective cohort study.

Objective: To compare days to diagnosis of pregnancy location for same-day medication abortion and same-day uterine aspiration with delayed treatment (expectant management) in patients with undesired pregnancy of unknown location (PUL).

Study Design: We conducted a retrospective cohort study at a single Planned Parenthood health center in Minnesota. We reviewed electronic health records and included patients presenting for induced abortion diagnosed with PUL (positive high-sensitivity urine pregnancy test and no evidence of intrauterine or extrauterine pregnancy on transvaginal ultrasonography) without symptoms or ultrasonographic imaging concerning for ectopic pregnancy (low risk). The primary outcome was days to pregnancy location clinical diagnosis.

Results: Of 19,151 abortion encounters in 2016-2019, 501 (2.6%) had a low-risk PUL. Participants chose delay-for-diagnosis before treatment (148, 29.5%), immediate treatment medication abortion (244, 48.7%), or immediate treatment uterine aspiration (109, 21.8%). Median days to diagnosis were significantly lower in the immediate treatment uterine aspiration group (2 days, IQR 1-3 days, p < 0.001) and similar for immediate treatment medication abortion (4 days, IQR 3-9 days, p = 0.304) compared with delay-for-diagnosis (3 days, IQR 2-10 days). Thirty-three low-risk participants (6.6%) were treated for ectopic pregnancy, but no difference in ectopic rate was detected among groups (p = 0.725). Participants in the delay-for-diagnosis group were more likely to be nonadherent with follow-up (p < 0.001). For participants who completed follow-up, abortion completion rate was lower for immediate treatment medication abortion (85.2%) compared with immediate treatment uterine aspiration (97.6%, p = 0.003).

Conclusions: For patients with undesired PUL, diagnosis of pregnancy location was fastest with immediate treatment uterine aspiration and similar for expectant management and immediate treatment medication abortion. Medication abortion efficacy may be reduced in treatment of undesired PUL.

Implications: For PUL patients desiring induced abortion, the option of proceeding at initial encounter may help improve access and patient satisfaction. Uterine aspiration for PUL may help diagnose pregnancy location more quickly.