Clinical Updates in Reproductive Health

Paracervical block

Last reviewed: October 7, 2022

Recommendation:

  • Paracervical block with local anesthetic is an effective method of pain management and should be a part of all vacuum aspiration, osmotic dilator placement and dilatation and evacuation (D&E) procedures.
  • Many types of health care workers-including associate and advanced associate clinicians, nurses, midwives, traditional and complementary medicine professionals, auxiliary nurses and auxiliary nurse midwives-can safely and effectively provide paracervical anesthesia.
  • Paracervical block is not effective for managing pain associated with fetal expulsion during medical abortion at or after 13 weeks gestation.
  • A paracervical block composed of 20mL of 1% lidocaine, injected to a depth of 3cm is recommended. If 1% lidocaine is unavailable, 10mL of 2% lidocaine may be substituted, although evidence supporting the use of 2% lidocaine is sparse. Either a two-point or a four-point paracervical injection technique should be used.

    In practice:

  • Paracervical block should be used for uterine evacuation procedures performed for both induced abortion and postabortion care.

Strength of recommendation: Strong

Quality of evidence: High

Local anesthesia for pain management

Vacuum aspiration

A 2013 systematic review evaluating paracervical block for gynecologic procedures requiring cervical dilation, including aspiration abortion before 13 weeks and uterine evacuation for incomplete abortion, found that paracervical block reduced pain during cervical dilation and uterine interventions, although not post-procedure pain, when compared to placebo or no anesthesia (Tangsiriwatthana et al., 2013). In the highest-quality study available on the use of paracervical block during vacuum aspiration, 120 women undergoing abortion before 11 weeks gestation were randomized to receive either a paracervical block – containing 20mL of 1% lidocaine buffered with sodium bicarbonate and injected to a depth of three centimeters at four paracervical points – or a sham injection where a capped needle was touched to the cervicovaginal junction to mimic administration of paracervical block. Participants who received the paracervical block had less pain during dilation and aspiration compared to those who received the sham injection (Renner et al., 2012). Deeper injection of anesthetic (3cm) improves pain management compared to superficial (1.5cm) injection (Cetin, & Cetin, 1997; Renner et al., 2010). A subsequent randomized controlled trial found the addition of sodium bicarbonate (1mL of 8.4% sodium bicarbonate for every 10mL of anesthetic solution) to a paracervical block containing 1% lidocaine did not decrease pain scores at the time of injection or at cervical dilation when compared to lidocaine only (Chin et al., 2020). It is unclear whether a four-point injection technique is superior to a two-point injection technique. In one randomized trial, a four-point technique was superior to a two-point technique, however differences in pain were small (Renner et al., 2016). In a different randomized trial, no differences in pain were found between two- and four-point techniques (Glantz & Shomento, 2001). A waiting period between injection and cervical dilation is not necessary, as it does not improve pain control (Phair, Jensen, & Nichols, 2002; Renner et al., 2016; Wiebe & Rawling, 1995).

It is unclear if the volume of anesthetic administered influences pain relief; a randomized trial including 114 people having uterine aspiration found no difference in reported pain when people received a 40mL 0.5% lidocaine or a 20mL 1% lidocaine paracervical block (Crouthamel et al., 2022), while two observational studies with significant confounding (variables?) showed that people who received a 20mL block reported lower pain scores than those who received a 10mL block (Allen et al. 2006; Wiebe, 1992).  Providers should avoid inadvertent intravascular injection to limit potential dose-related lidocaine toxicity (Lau et al., 1999), and may prefer a two-point injection technique when using a smaller volume of anesthetic.

For people receiving deep sedation for pain management, it is unclear if there is additional benefit to administering paracervical block (Kan, Ng, & Ho, 2004; Renner et al., 2010; Wells, 1992; Wong et al., 2002). When using general anesthesia, there is no additional benefit to administering paracervical block (Hall et al., 1997; Renner et al., 2010).

Dilatation and evacuation

No studies have evaluated paracervical block for pain management during D&E procedures without concomitant sedation or anesthesia. One randomized trial has examined paracervical block use during D&E when women also received deep sedation or general anesthesia; the addition of paracervical block did not improve postoperative pain (Lazenby, Fogelson, & Aeby, 2009). The recommendation to perform paracervical block for D&E has been extrapolated from data from vacuum aspiration studies and two randomized controlled trials assessing pain control during osmotic dilator placement before a D&E. One included 41 people and found significantly decreased pain during osmotic dilator placement when paracervical block was used (Soon et al., 2017). The other trial included 91 people and found that a smaller volume of anesthetic (12mL of 1% lidocaine) was noninferior to a larger volume (20mL of 1% lidocaine) in managing pain related to osmotic dilator placement (Shaw et al., 2021).

Medical abortion

No studies evaluate use of paracervical block for pain management during medical abortion before 13 weeks gestation. Two studies examining use of paracervical block during medical abortion at or after 13 weeks found no improvement in pain (Andersson et al., 2016; Winkler et al., 1997).

Who can perform paracervical block

The World Health Organization (WHO) makes service delivery recommendations for the provision of uterine aspiration, which includes routine administration of paracervical block (WHO, 2022). Health workers with the skills to perform a transcervical prodecure, and a bimanual pelvic examination to diagnose pregnancy and determine gestational age based on uterine size, can be trained to provide vacuum aspiration with paracervical block. WHO advises that uterine aspiration is within the scope of practice for specialty and general medical practitioners; and recommends the provision of vacuum aspiration by associate and advanced associate clinicians, midwives, and nurses based on moderate certainty evidence of safety and effectiveness. Traditional and complementary medical professionals are recommended to provide uterine aspiration based on low certainty evidence of safety and effectiveness, and WHO suggests that auxiliary nurses and auxiliary nurse midwives may be able to perform aspiration in settings where they provide basic emergency obstetric care (WHO, 2022). For more information about who can perform specific tasks related to abortion care, see Appendix C: World Health Organization recommendations for health worker roles in abortion care.

Technique

More information on paracervical block technique can be found in the Paracervical block technique job aid, linked below.

Resources

Pain Medication Table

Continuum of depth of sedation: Definition of general anesthesia and levels of sedation/analgesis

Paracervical Block Technique Job Aid

References

Allen, R. H., Kumar, D., Fitzmaurice, G., Lifford, K. L., & Goldberg, A. B. (2006). Pain management of first-trimester surgical abortion: Effects of selection of local anesthesia with and without lorazepam or intravenous sedation. Contraception, 74(5), 407-413.

Andersson, I. M., Benson, L., Christensson, K., & Gemzell-Danielsson, K. (2016). Paracervical block as pain treatment during second-trimester medical termination of pregnancy: An RCT with bupivacaine versus sodium chloride. Human Reproduction, 31(1), 67-74.

Cetin, A., & Cetin, M. (1997). Effect of deep injections on local anesthetics and basal dilatation of cervix in management of pain during legal abortions. A randomized, controlled study. Contraception, 56, 85-87.

Chin, J., Kaneshiro, B., Elia, J., Raidoo, S., Savala, M. & Soon R. (2020). Buffered lidocaine for paracervical blocks in first-trimester abortions: a randomized controlled trial. Contraception X, 18(2), 100044.

Crouthamel, B., Economou, N., Averback, S., Rible, R., Kully, G., Meckstroth, K., & Mody, S. (2022). Effect of paracervical block volume on pain control for dilation and aspiration: A randomized controlled trial. Obstetrics & Gynecology, 140(2), 234-242.

Glantz, J. C., & Shomento, S. (2001). Comparison of paracervical block techniques during first trimester pregnancy termination. International Journal of Gynecology & Obstetrics, 72, 171-8.

Hall, G., Ekblom, A., Persson, E., & Irestedt, L. (1997). Effects of prostaglandin treatment and paracervical blockade on postoperative pain in patients undergoing first trimester abortion in general anesthesia. Acta Obstetricia et Gynecologia Scandinavia, 76, 868-872.

Kan, A. S., Ng E. H., & Ho, P. C. (2004). The role and comparison of two techniques of paracervical block for pain relief during suction evacuation for first-trimester pregnancy termination. Contraception, 70, 159-163.

Lau, W. C., Lo, W. K., Tam, W. H., & Yuen, P. M. (1999). Paracervical anesthesia in outpatient hysteroscopy: A randomized double-blind placebo-controlled trial. BJOG: An International Journal of Obstetrics & Gynaecology,  106(4), 356-9.

Lazenby, G. B., Fogelson, N. S., & Aeby, T. (2009). Impact of paracervical block on postabortion pain in patients undergoing abortion under general anesthesia. Contraception, 80(6), 578-582.

O’Connell, K., Jones, H. E., Simon, M., Saporta, V., Paul, M., & Lichtenberg, E. S. (2009). First-trimester surgical abortion practices: A survey of National Abortion Federation members. Contraception, 79: 385–392.

Phair, N., Jensen, J. T., & Nichols, M. (2002). Paracervical block and elective abortion: The effect on pain of waiting between injection and procedure. American Journal of Obstetrics & Gynecology, 186, 1304-1307.

Renner, R.M., Jensen, J.T., Nichols, M.D., & Edelman, A. (2010). Pain control in first trimester surgical abortion: A systematic review of randomized controlled trials. Contraception, 81, 372-388.

Renner, R. M., Nichols, M. D., Jensen, J. T., Li, H., & Edelman, A. B. (2012). Paracervical block for pain control in first-trimester surgical abortion: A randomized controlled trial. Obstetrics & Gynecology, 119(5), 1030-1037.

Renner, R. M., Edelman, A. B., Nichols, M. D., Jensen, J. T., Lim J. Y., & Bednarek, P. H. (2016). Refining paracervical block techniques for pain control in first trimester surgical abortion: A randomized controlled noninferiority trial. Contraception, 95(5), 461-466.

Shaw, K.A., Lerma, K., Hughes, T., Hastings, C., Fok, W.K., & Blumenthal, P.D. (2021). A comparison of paracervical block volumes before osmotic dilator placement: A randomized controlled trial. Obstetrics & Gynecology, 138(3), 443-448.

Soon, R., Tschann, M., Salcedo, J., Stevens, K., Ahn, H. J., & Kaneshiro, B. (2017). Paracervical block for laminaria insertion before second-trimester abortion: A randomized controlled trial. Obstetrics & Gynecology, 130, 387-392.

Tangsiriwatthana, T., Sangkomkamhang, U.S., Lumbiganon, P., & Laopaiboon, M. (2013). Paracervical local anesthesia for cervical dilatation and uterine intervention. Cochrane Database of Systematic Reviews, 9, CD005056.

Wiebe, E. R. (1992). Comparison of the efficacy of different local anesthetics and techniques of local anesthesia in therapeutic abortion. American Journal of Obstetrics & Gynecology, 167, 131-4.

Winkler, M., Wolters, S., Funk, A., & Rath, W. (1997). Second trimester abortion with vaginal gemeprost-improvement by paracervical anesthesia? Zentralblatt fur Gynakologie, 119, 621-624.

Wells, N. (1992). Reducing distress during abortion: A test of sensory information. Journal of Advanced Nursing, 17(9), 1050-1056.

Wong, C. Y., Ng, E. H., Ngai, S. W., & Ho, P. C. (2002). A randomized, double-blind, placebo-controlled study to investigate the use of conscious sedation in conjunction with paracervical block for reducing pain in termination of first trimester pregnancy by suction evacuation. Human Reproduction, 17, 1222-1225.

World Health Organization. (2022). Abortion care guideline. Geneva: World Health Organization.

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