When we use the term 'people' in this summary, we mean individuals with a current ability to become pregnant.
Key messages
– A paracervical block, which is an injection of local anaesthetic around the cervix (neck of the womb), decreases pain with first trimester surgical abortion.
– Several studies examined ways to optimize the paracervical block such as depth of injection or number of injection sites.
– Overall people reported moderately high satisfaction with pain control and studies reported few side effects.
What is a first trimester surgical abortion?
First trimester surgical abortion is a medical procedure carried out by a trained healthcare provider to end a pregnancy at less than 14 weeks. Per year, 73 million abortions are performed worldwide. As the procedure is painful, it is important to offer effective pain management.
What did we want to find out?
It is unclear what the best method of management for this pain is. We were interested in what the evidence was for pain relief with local anaesthesia, including different types of local anaesthetics and the technique of using it.
Additionally, we wanted to know whether people were satisfied with their pain management or reported side effects.
What did we do?
We searched medical databases for studies that compared different pain management options for surgical abortion in the first 14 weeks of pregnancy. We summarized and compared the findings of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
We found 13 studies that involved 1992 people. All studies were conducted in hospitals or family planning clinics in five countries (the USA, Canada, Turkey, China, and Iran). The studies investigated different types of local anaesthesia.
Main results
A paracervical block decreases pain with a surgical abortion.
Several studies examined the best way to give the paracervical block. They found no benefit of giving people solutions that were less acidic, waiting longer after giving the injection to start the procedure, applying a gel rather than the injection, giving deeper injections, or giving more of them.
Overall people reported moderately high satisfaction with pain control and studies reported few side effects.
What are the limitations of the evidence?
Few studies compared the same treatment. As such, we could rarely compare their results. Our confidence in the evidence ranges from high to uncertain. This is because, for example, some results showed a very small difference in pain between study groups or the study only included people in an early stage of pregnancy (for example, seven weeks).
How up to date is this evidence?
The evidence is up to date to December 2022.
Evidence from this updated review indicates that a 20 mL 1% plain lidocaine PCB decreases pain during an abortion procedure. Evidence supports forgoing buffering lidocaine and a wait time between PCB injection and cervical dilation. A 1.5-cm deep injection as opposed to a 3-cm deep injection is sufficient. A two-site PCB injection as opposed to a four-site injection has similar effectiveness. Topical cervical anaesthesia (10 mL 2% lignocaine gel or 20 mg topical cervical lidocaine spray) as compared to placebo did not decrease pain based on moderate-certainty evidence, but then when compared to PCB, pain control was similar. Due to this inconsistency in evidence regarding the effectiveness of topical anaesthesia, its routine use is presently not supported. This review did not include studies of pain management with conscious sedation but, based on the results of our prior Cochrane review and the 2022 WHO guidelines, we recommend that the option of combination of pain management using conscious sedation plus PCB and non-steroidal anti-inflammatory drugs should be offered where conscious sedation is available as it further decreases pain.
Abortions prior to 14 weeks are among the most common outpatient surgical procedures performed on people capable of becoming pregnant. Various methods have been used to control pain; however, many people still experience pain with the procedure.
To evaluate the benefits and harms of local anaesthesia given for pain control during surgical abortion at less than 14 weeks' gestation.
We searched CENTRAL (Ovid EBM Reviews), MEDLINE (Ovid), Embase, POPLINE, and Google Scholar to December 2022 for randomized controlled trials of pain control in surgical abortion at less than 14 weeks' gestation using suction aspiration. We searched the reference lists of related reviews and articles.
We selected effectiveness and comparative effectiveness randomized controlled trials that studied local anaesthesia with common local anaesthetics and administration routes given for pain control in surgical abortion at less than 14 weeks' gestation using uterine aspiration. Outcomes included intraoperative pain, patient satisfaction, and adverse events.
We used standard Cochrane methods. We computed mean differences (MD) with 95% confidence intervals (CI) for continuous variables reporting a mean. We assessed the certainty of evidence using GRADE.
Thirteen studies with 1992 participants met the inclusion criteria. Due to heterogeneity of interventions, we could not pool more than two studies for any outcome. We used 13 mm improvement on a visual/verbal analogue scale to indicate a clinically meaningful difference in pain with surgical abortion (pain with dilation, aspiration, or during procedure). Based on type of pain control, we divided studies into three groups.
Paracervical block (PCB) effectiveness trials
A 20 mL 1% lidocaine PCB reduced pain with dilation (MD −37.00, 95% CI −45.64 to −28.36), and aspiration (MD −26.00, 95% CI −33.48 to −18.52) compared to a sham PCB (1 RCT, 120 participants; high-certainty evidence).
A PCB with 14 mL of 1% chloroprocaine resulted in a slight reduction in pain with aspiration compared to a PCB with normal saline injected at two or four sites (MD −1.50, 95% CI −2.45 to −0.55; 1 RCT, 79 participants; high-certainty evidence).
PCB comparative effectiveness trials
An ultracaine PCB probably results in little to no clinically meaningful difference in pain during procedure compared to topical cervical lidocaine spray (median 1 point higher, interquartile range (IQR) 0 to 3; P < 0.001; 1 RCT, 48 participants; moderate-certainty evidence). A 1000 mg dose of intravenous paracetamol probably does not decrease pain as much as ultracaine PCB during procedure (median 2 points higher, IQR 1 to 3; P < 0.001; 1 RCT, 46 participants; moderate-certainty evidence).
Various local anaesthetics in PCB comparative effectiveness trials
A 10 mL buffered 2% lidocaine PCB probably does not result in a clinically meaningful difference in pain with dilation compared to a plain lidocaine PCB (MD −0.80, 95% CI −0.89 to −0.71; 1 RCT, 167 participants; moderate-certainty evidence).
A buffered lidocaine PCB probably does not result in a clinically meaningful difference in pain with aspiration compared to plain lidocaine PCB (MD −0.57, 95% CI −1.01 to −0.06; 2 RCTs, 291 participants; moderate-certainty evidence).
Non-PCB local anaesthesia or PCB technique effectiveness trials
PCB: waiting versus no waiting
Waiting three to five minutes between 1% lidocaine PCB injection and dilation probably does not result in a clinically meaningful difference in pain with dilation compared to not waiting (MD −0.70, 95% CI −1.23 to −0.17; 2 RCTs, 357 participants; moderate-certainty evidence).
Topical cervical analgesia
Topical 10 mL 2% lignocaine gel probably does not result in a clinically meaningful difference in pain with aspiration compared to KY Jelly (MD −0.87, 95% CI −1.60 to −0.14; 1 RCT, 131 participants; moderate-certainty evidence).
In participants who also received a PCB, 20 mg topical cervical lidocaine spray probably does not result in a clinically meaningful difference in pain during the procedure compared to two pumps of normal saline spray (median −1 point, IQR −2 to −1; P < 0.001; 1 RCT, 55 participants; moderate-certainty evidence).
Intravenous paracetamol 1000 mg compared to two pumps of cervical lidocaine spray probably does not results in a clinically meaningful difference in pain procedure (median 1 point, IQR −2 to 2; P < 0.001; 1 RCT, 48 participants; low-certainty evidence).
Non-PCB local anaesthesia or PCB technique comparative effectiveness trials
Depth of PCB
The evidence suggests that a 3-cm deep PCB probably does not result in a clinically meaningful difference in pain with aspiration compared to a 1.5-cm deep PCB (MD −1.00, 95% CI −1.09 to −0.91; 2 RCTs, 229 participants; low-certainty evidence).
PCB: four sites versus two sites
A two-site (4-8 o'clock) 20 mL 1% lidocaine PCB does not result in a clinically meaningful difference in pain with dilation compared to a four-site (2-4-8-10 o'clock) PCB (MD 8.60, 95% CI 0.69 to 16.51; 1 RCT, 163 participants; high-certainty evidence).
Overall, participants reported moderately high satisfaction with pain control and studies reported few adverse events.