Effect of needle diameter on pain during oocyte retrieval—a randomized controlled trial

Use of a thinner retrieval needle results in significantly and clinically relevantly lower pain scores during and after oocyte retrieval.

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VOLUME 115, ISSUE 3, P683-691, MARCH 01, 2021


Erato Terpsichori Iduna Antigoni Buisman, M.D.,a,b Jan Peter de Bruin, M.D., Ph.D.,a
Didi Dorothea Maria Braat, M.D., Ph.D.,b and Jan Willem van der Steeg, M.D., Ph.D.a



To study pain in women undergoing oocyte retrieval with a reduced needle (20/17 gauge) compared to a standard needle (16 gauge).


Single-center randomized controlled trial.


Fertility clinic.


Women undergoing their first oocyte retrieval for in vitro fertilization or intracytoplasmic sperm injection.


Oocyte retrieval with a reduced needle (20/17 gauge) or with a standard needle (16 gauge).

Main Outcome Measures

The primary outcome measure was intraoperative pain on an 11-point visual analogue scale (VAS). Secondary outcome measures included the following: dosage of fentanyl requested; pain at 5, 15 and 30 minutes after retrieval; and pain and analgesia until 4 days after retrieval.


A total of 47 women were randomized for the reduced needle (RN) and 48 for the standard needle (SN). Pain scores were significantly lower during and after retrieval with the RN. During retrieval, mean VAS scores in the RN group were 4.3 versus 6.3 in the SN group. Pain remained significantly lower in the RN group after retrieval, with VAS-scores of 1.2 vs. 2.1 directly after retrieval, 0.0 versus 2.0 5 minutes after retrieval, and 0.0 versus 1.0 30 minutes after retrieval. In the RN group, three patients (6.4%) requested more fentanyl during the procedure, versus 16 (33.3%) in the SN group. A total of 79 patients submitted their follow-up questionnaire (response rate 83%). Pain on the first 2 days following retrieval was significantly less in the RN group, with VAS scores of 1.6 versus 2.4 in the SN group, and 1.2 versus 2.5. In line with this finding, fewer patients in the RN group took analgesia on the days after the procedure. This difference was statistically significant only on day 3.


Use of a thinner needle results in significantly and clinically relevant lower pain scores during oocyte retrieval, and patients in the reduced needle group requested significantly less analgesia during oocyte retrieval than patients in the standard needle group. Pain scores remained significantly lower up until 2 days after the procedure.

Dutch Trial Registration Number

Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders.