Clinical Updates in Reproductive Health

Paracervical block

Last reviewed: January 13, 2020

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.
  • Midlevel providers 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. Where available and where staff have been trained to do so, sodium bicarbonate (1mL of 8.4% sodium bicarbonate for every 10mL of anesthetic solution) may be added to the paracervical block.

Strength of recommendation: Strong

Quality of evidence: Moderate

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 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, Sangkomkamhang, Lumbiganon, & Laopaiboon, 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. Women who received the paracervical block had less pain during dilation and aspiration compared to women who received the sham injection (Renner, Nichols, Jensen, Li, & Edelman, 2012). Deeper injection of anesthetic (3cm) improves pain management compared to superficial (1.5cm) injection (Cetin, & Cetin, 1997; Renner, Jensen, Nichols, & Edelman, 2010). Adding sodium bicarbonate (1mL of 8.4% sodium bicarbonate for every 10mL of anesthetic solution) to lidocaine decreased pain during paracervical block injection in one study (Wiebe & Rawling, 1995), and during cervical dilation in another (Wiebe, 1992); however differences in reported pain between groups in each of these studies were small. Adding sodium bicarbonate increases the cost and complexity of using a paracervical block. Furthermore, 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 women’s 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).

There are no trials that directly compare a block composed of 20mL of 1% lidocaine to one that contains 10mL of 2% lidocaine during abortion. It is unclear if the volume of anesthetic administered influences pain relief; two studies show that women who received a 20mL block reported lower pain scores than those who received a 10mL block (Allen, Kumar, Fitzmaurice, Lifford, & Goldberg, 2006; Wiebe, 1992).  However, confounding factors such as different doses of anesthetic and different injection techniques between study groups may have influenced the outcome. When using a paracervical block composed of 10mL of 2% lidocaine, providers should avoid inadvertent intravascular injection to limit potential dose-related lidocaine toxicity (Lau, Lo, Tam, & Yuen, 1999); furthermore, they should consider  the two-point injection technique rather than the four-point technique.

In women who receive 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, Ng, Ngai, & Ho, 2002). When women receive general anesthesia, there is no additional benefit to administering paracervical block (Hall, Ekblom, Persson, & Irestedt, 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 one randomized controlled trial of 41 women undergoing D&E which found significantly decreased pain during osmotic dilator placement when paracervical block was used (Soon, Tschann, Salcedo, Stevens, Ahn, & Kaneshiro, 2017).

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 women’s pain (Andersson, Benson, Christensson, & Gemzell-Danielsson, 2016; Winkler, Wolters, Funk, & Rath, 1997).

Midlevel providers

In an international, randomized multi-center study examining 2,894 procedures, midlevel providers had similar complication rates as physicians when performing vacuum aspiration with paracervical block (Warriner et al., 2006). The midlevel providers experienced no complications related to use of paracervical block.

Technique

More information on paracervical block technique can be found in the “Paracervical block technique” section and in the Paracervical Block Technique Job Aid below.

Resources

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. Contraception74(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.

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 anesthesiaContraception80(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. Contraception79: 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.

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.

Warriner, I. K., Meirik, O., Hoffman, M., Morroni, C., Harries, J., My Huong, N. T., & Seuc, A. H. (2006). Rates of complication in first-trimester manual vacuum aspiration abortion done by doctors and midlevel providers in South Africa and Vietnam: A randomised controlled equivalence trial. The Lancet, 368(9551), 1965-1972.

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.

Wiebe, E. R., & Rawling, M. (1995). Pain control in abortion. International Journal of Gynecology & Obstetrics, 50, 41-46.

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.