Once pregnancy is confirmed by a urine hCG, pregnancy dating should be established. When pregnancy dating cannot be reasonably determined by other means, ultrasound should be used (NAF CPG 2020). Its use is not a requirement for medication abortion provision (NAF, SFP, ACOG, FDA, Ipas, WHO). Studies demonstrate the safety of eliminating routine ultrasound from medication abortion care (Raymond 2018, Schonberg 2014, Clark 2007, Bracken 2011). This helps streamline care, and avoid cost and delays.
Ultrasound Indications for Medical Abortion
(Adapted from RHEDI, NAF)
- Data supports accuracy of pregnancy dating by LMP alone with low rates of over- and under-estimation through mid-first trimester (<63 days LMP). This can likely be reasonably extended to include pregnancies to 70 days and beyond, depending on your practice setting, though explicit evidence is lacking.
The absence of the pregnancy (gestational sac or embryo depending the US findings prior to MAB) and the presence
|PERSISTENT GESTATIONAL SAC
AFTER MEDICATION ABORTION
This transvaginal ultrasound shows the presence of an empty gestational sac. Patients can choose their preferred management option: waiting for spontaneous completion, repeat misoprostol (expels GS > 60% of time (Reeves 2008)), or an aspiration procedure. (Or repeat mifepristone and misoprostol but minimal data on efficacy).