Pain control in first-trimester and second-trimester medical termination of pregnancy: a systematic review

Abstract

Background: Pain is a predictable feature of medical abortion in both the first trimester and the second trimester. We sought to evaluate optimal analgesia regimens during medical abortion.

Study design: We searched the PubMed and Cochrane databases from inception to March 2010 for publications of trials comparing methods of pain control during first-trimester medical abortion (<12 completed weeks' gestation) and second-trimester medical abortion (13-24 completed weeks' gestation). Standard data abstraction templates were used to systematically assess and summarize data.

Results: Of 363 articles, 10 articles reporting the results of nine studies met inclusion criteria. Heterogeneity of analgesia regimens and medical abortion protocols prevented meta-analysis. Four studies conducted in women with pregnancies <8 completed weeks' gestation found that prophylactic acetaminophen, acetaminophen+codeine, ibuprofen or alverine did not reduce medical abortion pain; however, administration of ibuprofen after onset of cramping reduced pain and subsequent analgesia use. In second-trimester medical abortion, one study found that women treated with fentanyl (50 mcg) patient-controlled analgesia (PCA) had better satisfaction and pain relief than women treated with fentanyl (25 mcg) or morphine PCA, but found no difference in delivery/demand ratio; three studies found little effect of adjuvant treatment with metoclopramide or paracervical block on pain; one study found that women at >15 weeks' gestation who received diclofenac with the first misoprostol dose required less opioid analgesia than women who received acetaminophen+codeine.

Conclusion: Few studies examine pain management during medical abortion, and heterogeneity of existing data limits comparison. Further research is needed to determine the optimal analgesia regimens for first-trimester and second-trimester medical termination of pregnancy. To facilitate comparability of data, researchers should use contemporary medical abortion regimens, outcomes and study instruments to measure pain.