There are several different surgical techniques for early termination of pregnancy (abortion in the first three months). These are dilatation and curettage (D&C to scrape out the contents of the uterus), vacuum aspiration (sucking out the contents of the uterus with a manual or power-operated device). Hysterotomy (surgery through the uterus, like caesarean section) is not commonly used. The cervix (opening of the uterus) can be prepared beforehand with hormones to minimise the risk of damage. The review found that both, D&C and vacuum aspiration, are safe and effective methods for first trimester termination of pregnancy and complications are rare. The review does not reveal women's or surgeons' preference of one method over the other.
Complications for surgical first trimester abortion are rare. The included studies do not indicate overall benefits of one over the other method. MVA can be used for early first trimester surgical abortion, but maybe more difficult when used later in the first trimester. Duration of procedure is shorter with VA compared to D&C, which may be of importance when using local anaesthetics or for busy clinics. Outcomes such as women's satisfaction, the need for pain relief or surgeons preference for the instrument have been inadequately addressed. No long-term outcomes, such as fertility after surgical abortion, are available.
Different surgical methods for termination of pregnancy have evolved over the years: Dilatation and curettage, power operated vacuum aspiration (VA), manual vacuum aspiration (MVA) or hysterotomy. Local or general anaesthesia is used for all methods. Preabortion medical or mechanical cervical preparation may reduce the incidence of cervical or uterine injuries.
To compare the safety and efficacy of different surgical methods for first trimester abortion.
The Cochrane Controlled Trials Register has been searched. A search of the reference lists of identified trials was performed. An additional MEDLINE search was done using the Internet search service Pub Med.
Randomised controlled trials comparing different surgical methods for first trimester abortion were eligible.
Trials under consideration were evaluated for methodological quality and appropriateness for inclusion. Eleven trials were included, resulting in 3 comparisons: 1) vacuum aspiration versus dilatation and curettage, 2) flexible versus rigid vacuum aspiration cannula, 3) manual vacuum aspiration versus electrical vacuum aspiration. Results are reported as risk ratio for dichotomous data and weighted mean differences for continuous data.
There were no reports of maternal deaths in the trials identified.
Vacuum aspiration versus dilatation and curettage:
There were no statistically significant differences for excessive blood loss, blood transfusion, febrile morbidity, incomplete or repeat uterine evacuation procedure, re-hospitalisation, post operative abdominal pain or therapeutic antibiotic use. Duration of operation was statistically significantly shorter with vacuum aspiration compared to D&C in both gestational age subgroups : < 9 weeks: weighted mean difference (WMD) -1.84 minutes, 95% confidence interval (CI) [-2.542,-1.138]; =/> 9 weeks: WMD -0.600 minutes, 95% CI [-1.166,-0.034]).
Flexible versus rigid vacuum aspiration cannula:
There were no statistically significant differences with regard to cervical injuries, febrile morbidity, blood transfusion, therapeutic antibiotic use, or incomplete or repeat uterine evacuation procedure.
Manual vacuum aspiration versus electrical vacuum aspiration:
Severe pain was reported less often with MVA compared to VA in women with < 9 weeks of amenorrhoea ( RR 0.73; 95% CI 0.47 to 1.16). In women with amenorrhoea > 9 weeks, severe difficulty of the procedure was reported more frequently with MVA compared to VA ( RR 5.7; 95%CI 2.45 to 13.28). There was no difference in cervical injuries, excessive blood loss, blood transfusion, febrile morbidity, repeat uterine evacuation, duration of operation and women's preference between the two groups.