Comparison of medication abortion outcomes at less than and greater than 6 weeks gestation

To compare outcomes and characteristics of two cohorts of patients: those receiving medication abortion (MAB) at ≤42 days gestation and those at 43 to 56 days gestation.

We conducted a retrospective cohort study in 2022, comparing 142 patients accessing MAB at ≤42 days with 200 patients at 43 to 56 days. We sought to detect a 7% difference in MAB success with 80% power and alpha of 0.05. We assessed follow-up responses and unscheduled contacts with the health care system.

Abortion success rates were similar between the ≤42-day and 43 to 56-day groups (94.3% vs 97%, p = 0.226). Those ≤42 days had more unscheduled office visits (13% vs 6%, p = 0.01) but no difference in phone calls or emergency room visits. More patients with successful MAB in the ≤42-day group answered that bleeding (11.7% vs 1.9%, p = 0.006) and cramping (10.5% vs 2.9%, p = 0.035) were not heavier or worse than a period and that they had no pregnancy symptoms prior to the abortion (15.8% vs 6.0%, p = 0.034). Patients ≤42 days gestation less often had a pretreatment ultrasound (48% vs 64%, p = 0.004). Patients without prior ultrasound more often needed uterine aspiration to complete the abortion (6.8% vs 2%, p = 0.027).

Patients undergoing MAB at ≤42 days have similar success rates but more unscheduled office visits, and more ambiguous symptoms when using standardized questions for evaluating abortion success. Clinicians should adapt anticipatory guidance and counseling for this population.

Access to very early abortion is increasingly relevant as legal restrictions on abortion increase. Earlier gestations may have different responses to standard follow-up questions despite a successful MAB and may have more interactions with the health care system.