Last reviewed: January 29, 2021
- Cervical preparation is recommended after 12-14 weeks gestation. Before 12-14 weeks gestation, cervical preparation may be considered, but should not be routinely used.
- Recommended methods for cervical preparation include:
- Misoprostol 400mcg sublingually 1-3 hours before the procedure.
- Misoprostol 400mcg vaginally or buccally 3 hours before the procedure.
- Osmotic dilators placed in the cervix 6-24 hours before the procedure.
- Mifepristone 200mg orally 1-2 days before the procedure.
Strength of recommendation: Strong
Quality of evidence: Moderate
Benefits of cervical preparation
A meta-analysis of 51 randomized controlled clinical trials of cervical preparation through 13 weeks gestation found that procedure time was shorter with cervical preparation but there were no differences in serious complications, such as cervical laceration or uterine perforation, in women given cervical preparation compared to those given placebo (Kapp, Lohr, Ngo, & Hayes, 2010). In the largest multicenter randomized controlled trial, which included 4,972 women given either misoprostol 400mcg vaginally or placebo three hours before a vacuum aspiration, there was no difference in the rates of cervical laceration, perforation or infection between the two groups (Meirik, Huong, Piaggio, Bergel, & von Hertzen, 2012). However, a significant decrease in the risk of incomplete abortion was observed in those who received misoprostol for cervical preparation (<1%) compared to the placebo group (2%), but side effects were more frequent for women who were given misoprostol. For women at higher risk of complications during cervical dilation (young women, women with cervical abnormalities or prior cervical surgery) or for inexperienced providers, there may be a benefit from cervical preparation before 12-14 weeks gestation (Allen & Goldberg, 2016; Grimes, Schulz, & Cates, 1984; Kaunitz, Rovira, Grimes, & Schulz, 1985).
Side effects of cervical preparation
In the largest randomized controlled trial of misoprostol for cervical preparation, 55% of women who took misoprostol complained of pre-procedure abdominal pain and 37% had vaginal bleeding, compared to 22% and 7% in the placebo group (Meirik et al., 2012). In addition, cervical preparation adds cost, complexity and time to an abortion, as women must visit the clinic a day before the procedure to have osmotic dilators placed or to receive mifepristone, or must wait in the health center for misoprostol to take effect. Because abortion before 13 weeks gestation is very safe, the gestational age at which the benefit of routine cervical preparation outweighs the side-effects is not known (Kapp et al., 2010). Women’s satisfaction with cervical preparation has not been systematically studied in randomized controlled trials but is an important consideration for quality of care and service delivery (Kapp et al., 2010).
Choice of methods
The choice of misoprostol, mifepristone or osmotic dilators for cervical preparation depends on availability, expense, convenience and preference. Sublingual misoprostol has superior effectiveness but more gastrointestinal side effects than vaginal misoprostol (Kapp et al., 2010; Saav, Kopp Kallner, Fiala, & Gemzell-Danielsson, 2015; Saxena, Sarda, Salhan, & Nanda, 2008). Mifepristone given 24 hours prior to the abortion is superior to misoprostol but adds time and expense to the abortion procedure (Ashok, Flett, & Templeton, 2000; Kapp et al., 2010). Misoprostol and osmotic dilators have similar effectiveness but dilator placement is associated with increased pain, increased time to procedure and reduced satisfaction for women (Bartz, et al., 2013; Burnett, Corbett, & Gertenstein, 2005; MacIsaac, Grossman, Balistreri, & Darney, 1999).
Adolescents may benefit from cervical preparation due to their increased risk of cervical injury during abortion (Allen & Goldberg, 2016; Schulz et al., 1983). This risk is independent of nulliparity (Meirik et al., 2014); adolescents have physiologically immature cervices that may be more difficult to dilate regardless of obstetric history (Allen & Goldberg, 2016; Schulz et al., 1983). There are no clinical trials examining the use of cervical preparation in this patient population.
Allen, R., & Goldberg, A. (2016). Society of Family Planning Clinical Guideline 20071: Cervical dilation before first trimester surgical abortion (< 14 weeks gestation). Contraception, 93(4), 277-291.
Ashok, P. W., Flett, G. M., & Templeton, A. (2000). Mifepristone versus vaginally administered misoprostol for cervical priming before first-trimester termination of pregnancy: A randomized, controlled study. American Journal of Obstetrics & Gynecology, 183(4), 998-1002.
Bartz, D., Maurer, R., Allen, R., Fortin, J., Kuang, B., & Goldberg, A. (2013). Buccal misoprostol compared with synthetic osmotic cervical dilator before surgical abortion: A randomized controlled trial. Obstetrics & Gynecology, 122, 57-63.
Burnett, M. A., Corbett, C. A., & Gertenstein, R. J. (2005). A randomized trial of laminaria tents versus vaginal misoprostol for cervical ripening in first trimester surgical abortion. Journal of Obstetrics and Gynaecology Canada, 27(1), 38-42.
Grimes, D. A., Schulz, K. F., & Cates, W. J., Jr. (1984). Prevention of uterine perforation during curettage abortion. Journal of American Medical Association, 251(16), 2108-2111.
Kapp, N., Lohr, P. A., Ngo, T. D., & Hayes, J. L. (2010). Cervical preparation for first trimester surgical abortion. The Cochrane Database of Systematic Reviews (2), CD007207.
Kaunitz, A. M., Rovira, E. Z., Grimes, D. A., & Schulz, K. F. (1985). Abortions that fail. Obstetrics & Gynecology, 66(4), 533-537.
MacIsaac, L., Grossman, D., Balistreri, E., & Darney, P. (1999). A randomized controlled trial of laminaria, oral misoprostol, and vaginal misoprostol before abortion. Obstetrics & Gynecology, 93(5 Pt 1), 766-770.
Meirik, O., Huong, N. T., Piaggio, G., Bergel, E., & von Hertzen, H. (2012). Complications of first-trimester abortion by vacuum aspiration after cervical preparation with and without misoprostol: A multicentre randomised trial. The Lancet, 379(9828), 1817-1824.
Saav, I., Kopp Kallner, H., Fiala, C., & Gemzell-Danielsson., K. (2015). Sublingual versus vaginal misoprostol for cervical dilatation 1 or 3 h prior to surgical abortion: A double blinded RCT. Human Reproduction, 30(6), 1314-1322.
Saxena P., Sarda, N., Salhan, S., & Nandan, D. (2008). A randomised comparison between sublingual, oral and vaginal route of misoprostol for pre-abortion cervical ripening in first-trimester pregnancy termination under local anesthesia. Australian and New Zealand Journal of Obstetrics and Gynaecology, 48(1), 101-6.
Schulz, K. F., Grimes, D. A., & Cates, W., Jr. (1983). Measures to prevent cervical injury during suction curettage abortion. The Lancet, 1(8335), 1182-1185.
World Health Organization. (2014). Clinical practice handbook for safe abortion. Geneva: World Health Organization Press.