3 May 2011
Clinical Update: Very early surgical abortion
By Patricia A. Lohr, Medical Director, BPAS.
Q) What is meant by very early surgical abortion?
This typically refers to abortion carried out at gestations under 7 weeks. Early studies showed that the risk of a failed abortion was higher under 7 weeks’ gestation especially when a suction cannula with a diameter in millimetres smaller than the gestational age in weeks was used for the procedure. (1) In this study, abortions performed at less than or equal to 6 weeks’ gestation had a failure rate of 5.6/1000 compared to 1.9/1000 for those performed at 7 to 12 weeks’ gestation. As a result, most providers would not perform a surgical procedure in the earliest weeks of pregnancy, deferring the woman’s procedure until after 7 or sometimes 8 weeks’ gestation.
Q) Why has very early surgical abortion not always been used?
Advisory bodies have been cautious about recommending vacuum aspiration for very early abortions in light of the evidence about method failure. The 2004 guideline of the Royal College of Obstetricians and Gynaecologists (RCOG) stated that, unless a particular rigorous protocol was used, suction termination ‘is better deferred until the pregnancy exceeds 7 weeks of gestation’. The availability of medical abortion with mifepristone and misoprostol, which had been studied from the earliest weeks of pregnancy and shown to be highly effective, was also seen as a valid, if not better, alternative.
Q) What has changed with regard to very early surgical abortions?
In the past, urine and serum pregnancy tests were not very sensitive, there was limited access to ultrasound, the products of conception were rarely examined, and very early surgical abortions had been shown to have a higher risk of continuing pregnancy. There was also a concern about missing an ectopic pregnancy because the collection of blood in the uterus which can occur with an extra-uterine gestation can have the appearance of a very early gestational sac. So, if a pseudosac was seen on ultrasound and the abortion performed without looking at the aspirate to make sure a gestational sac had been removed, women might be reassured inappropriately following the procedure.
Today, vaginal ultrasound is more readily available and we have a better understanding of the importance of checking the uterine aspirate to make sure a gestational sac is seen. When a gestational sac is not seen, an immediate transvaginal ultrasound can be done to see if the sac was missed and if it was not, serum beta-hCG testing can be performed. The purpose of the serum beta-hCG measurements is to check whether the hormone level is declining rapidly (as one would expect with a successful abortion), going up (as with a continuing pregnancy), or not changing (which may be indicative of an ectopic pregnancy). Importantly, there have been two large case series published (2) that have shown that using a protocol employing these measures leads to a safe, successful abortion almost all of the time and picks up problems, like missed abortions and ectopic pregnancies, very rapidly.
Perhaps most importantly, pregnancy is now detectable by women using home testing kits as early as the third or fourth week of gestation. This has led to an increased demand for early abortion. The increasing availability of early medical abortion has also raised expectations that termination can be accessed very early in pregnancy and has very likely contributed to the increase in abortions performed below 10 weeks’ gestation in England and Wales. (3) But for some women, medical abortion may be neither preferable nor advisable, and having a surgical option is important to them. Women find being told to wait for a surgical abortion until they are ‘pregnant enough’ both stressful and counter-intuitive. The evidence certainly supports women’s feelings with regard to safety; the earlier an abortion is performed, the lower the risks. (4)
Q) What is the protocol for very early surgical abortion?
In the paper by Creinin and Edwards, careful gestational age dating was performed with vaginal scanning and when a sac wasn’t seen in the uterus, a serum beta-hCG level was obtained to make sure it was below the level at which one would expect a sac to be visible on scan. If the level was above this discriminatory zone, the woman would be immediately referred for an ectopic pregnancy work-up. For anyone else, which included some women in which no sac was seen in the uterus, an evacuation was done with a manual vacuum aspirator and a size 7 cannula and the aspirate inspected to ensure the sac was seen. In cases where it was not seen, a vaginal scan was performed straight away and a re-aspiration done if the sac remained in the uterus. If a sac was not seen on scan, serum beta-hCGs were done with referral for an ectopic pregnancy work up if indicated by the levels. With this protocol, they reported a failed abortion rate of 1.3/1000 which was comparable to the rate reported in the Kaunitz study for gestations of 7 to 12 weeks.
Q) Is there a difference between EVA and MVA?
There is some limited evidence that evacuation using a manual vacuum aspirator causes less destruction to the gestational sac, making it easier to visualise in the aspirate. (5) One large case series has been published which allowed electric vacuum aspiration or manual vacuum aspiration to be used in a similar protocol to that described by Creinin and Edwards reported a higher failure rate. (6) In this study, the failure rate was slightly higher in the EVA group, but in general more failed procedures were reported in this study than in the series by Creinin and Edwards (1.5%, 95% CI 0.9%-2.4%). What is still needed is a randomised trial comparing manual and electric vacuum aspiration to determine which is better.
Q) What method is used at BPAS?
At BPAS, we have a protocol that is very similar to the one described by Creinin and Edwards. Evacuation using a manual vacuum aspirator is allowed as soon as a gestational sac is seen on scan and diligent inspection of the aspirate must confirm that a gestational sac was removed. Where a complete evacuation cannot be confirmed, referral is made to an Early Pregnancy Assessment Unit to ensure that the woman does not have an ectopic pregnancy. In the event that she does have an ectopic pregnancy, she is in the right place to be treated promptly.
We have had a positive response to the availability of very early surgical abortion, but there are still challenges to be addressed. These include the need to train surgeons in this technique and ensuring access to serum beta hCG testing, which means collaborating closely with our colleagues in the NHS or developing that capability at bpas. It would also be very valuable to have a randomised controlled trial performed comparing outcomes with early medical abortion using mifepristone and misoprostol and surgical abortion using these methods.
While we feel it is important to offer women a choice of procedures at every gestation, we also recognise that accurate counselling about the relative risks and benefits of any procedure we provide is an essential part of good patient care. The results of a head-to-head trial would help this greatly, but in the end it is for patients to weigh up the profile of any given treatment option and choose what is right for her. Retaining choice in abortion treatments, buttressed by better evidence of a safe method of providing early surgical abortion, has underpinned this service’s development at BPAS.
Patricia Lohr’s Clinical Update column appears in the Spring 2011 print edition of Abortion Review. Download a .pdf of the print edition here.
Abortion Review topic archive: Clinical Update Q&A
(1) Kaunitz AM, Rovira EZ, Grimes DA, Schulz KF. Abortions that fail. Obstetrics and Gynecology. 1985 Oct;66(4):533-7.
(2) Creinin MD, Edwards J. Early abortion: surgical and medical options. Current Problems in Obstetrics, Gynecology and Fertility 1997;20:6–32; Paul ME, Mitchell CM, Rogers AJ, Fox MC, Lackie EG. Early surgical abortion: efficacy and safety. American Journal of Obstetrics and Gynecology 2002;187:407–11.
(3) Department of Health. Statistical Bulletin 2010/1:Abortion Statistics, England and Wales: 2009. London:Crown, 2010.
(4) Bartlett LA. Berg CJ, Shulman HB, Zane SB, Green CA, Whitehead S, Atrash HK. Risk factors for legal induced abortion-related mortality in the United States. Obstetrics and Gynecology 2004;103:729–37.
(5) Goldberg AB, Dean G, Kang MS, Youssof S, Darney PD. Manual versus electric vacuum aspiration for early first-trimester abortion: a controlled study of complication rates. Obstetrics and Gynecology 2004 Jan;103(1):101-7.
(6) Paul ME, Mitchell CM, Rogers AJ, Fox MC, Lackie EG. Early surgical abortion: efficacy and safety. American Journal of Obstetrics and Gynecology 2002 Aug;187(2):407-11.