There is strong evidence for the use of routine antibiotic prophylaxis in patients undergoing uterine aspiration for abortion. Patients who received antibiotics were 0.59 times as likely to experience post-abortal infection compared to those who received placebo in a Cochrane review of 15 randomized controlled trials (Low 2012). This protective effect was evident in patients with and without risk factors (history of PID, positive CT, or pre-procedural BV). Limited evidence suggests that routine antibiotics are optional for asymptomatic patients undergoing uterine aspiration for EPL (Prieto 1995).

Evidence supports pre-procedure dosing of prophylactic antibiotics for the maximal effect, and the shortest possible course to give the lowest risk of adverse reactions and antibiotic resistance (Achilles 2011). Effective regimens include metronidazole or tetracyclines (e.g. doxycycline) or azithromycin. Despite varying practices in choice of antibiotic and duration of use, there is little data to support post-procedure antibiotics (Achilles 2011) which are often used to maintain NPO status prior to an abortion.


There has been much research into the role of misoprostol and other methods of cervical ripening for uterine aspiration. Cervical preparation with misoprostol is generally safe and may decrease procedure time for some patients, but it is not routinely indicated prior to a first trimester uterine aspiration due to increased waiting time, bleeding, cramping, other side effects, and minimal demonstrated benefit in terms of ease of dilation or pain (Ipas 2016,  Kapp 2010, Allen 2007). Its use can be considered on an individual basis when a challenging dilatation is anticipated (such as history of difficult dilation). An early study suggests the priming interval for first trimester may be 1 hour after sublingual administration, but with vaginal and buccal administration, 2 to 3 hours provides a better effect (Saav 2015).  The most common regimen prior to first trimester aspiration abortion is 400 mcg.


While past guidelines recommended all Rh-negative patients be tested and receive anti-D immunoglobulin regardless of gestational age or procedure type, new evidence has called this into question. New flow cytometry studies show fetal red blood cell exposure in the first trimester is below the calculated threshold for maternal Rh sensitization (Horvath 2020, Hollenbach 2019).  It is postulated that risk of sensitization is lower in medication abortion and early pregnancy loss, and somewhat higher with aspiration or curettage. The following recommendations have emerged (NAF CPGs 2020, Mark 2019)  and may evolve with research:

  • Only patients > 56 days from LMP with unknown Rh status should have Rh status documented.
  • Patient report is adequate for documentation. If patient does not know Rh status, spot, slide, or Eldon card testing methods may be used.
  • Rh status or informed waiver declining Rh testing must be documented >56 days.
  • Rh testing may be omitted if patient wants no future children, or declines testing.
  • When Anti-D IG indicated, use: 50 mcg at < 13 wks, or 300 mcg at > 13 wks.
  • Second injection only indicated if last was > than 3 weeks earlier (Bichler 2003).
  • Anti D antibodies may be present if a patient had anti-D IG injection within the last 3 months or was sensitized from a prior pregnancy.
  • For those sensitized, an additional anti-D IG injection will not prevent isoimmunization.


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