A randomized controlled study comparing pain experience between a newly designed needle with a thin tip and a standard needle for oocyte aspiration

Abstract

BACKGROUNDUltrasound-guided transvaginal oocyte retrieval is often performed under local anaesthesia on an outpatient basis. The objective of this study was to compare the overall pain experience of a newly designed reduced needle (RN) compared with a thicker standard needle (SN).METHODSA prospective, randomized, multi-centre study was performed at four different clinics from June to December 2009. The oocyte aspiration was performed under local anaesthesia, either with a needle with a reduced diameter (0.9 mm) for the last 50 mm from the tip (RN) or with a SN (1.4 mm). A total of 257 patients were randomized (RN: n = 129; SN: n = 128). The primary endpoint was the overall pain experience self-assessed and registered by the patient on a visual analogue scale (VAS 0 mm = no pain to 100 mm = unbearable pain) immediately after the oocyte retrieval. Secondary end-points such as vaginal bleeding and several embryological parameters were also registered.RESULTSThe overall pain during the oocyte retrieval procedure was significantly lower in the RN group than in the SN group (mean 21.0 mm, SD 17.5 mm and median 19.0 mm versus mean 26.0 mm, SD 19.9 mm and median 24.0 mm; P = 0.040, difference between groups mean−5.0 mm, 95% CI: 9.7 to−0.4). This was also true when adjusting for baseline characteristics such as number of follicles, number of previous oocyte pick-up, body mass index and age, by a multiple linear regression analysis. Significantly more patients (40 of 126) had less than expected vaginal bleeding in the RN group when compared with the SN group (24 of 124; 32 versus 19%; P = 0.03 and 95% CI 1.7–23.0%). No differences were found between the two needles with regard to additional i.v. analgesia, aspiration time, oocyte recovery, fertilization, cleavage rate, number of good quality embryos, number of embryos for freezing and pregnancy rate.CONCLUSIONSOocyte aspiration performed with the newly designed thinner-tipped needle resulted in significantly less overall pain and less vaginal bleeding, without prolonging the retrieval procedure or influence the oocyte recovery rate, when compared with a SN.Clinicaltrials.gov: NCT00924885

Degenerated oocyte in the cohort adversely affects IVF outcome

“…In multivariate analysis, we found that using 17-20G needle was significantly correlated with a higher number of DEG oocytes at OPU and a significantly worse morphokinetics score. However, in agreement with Wikland et al [ 30 ] our study did not show any difference between the two needles in pregnancy rates.…”

A pilot trial of large versus small diameter needles for oocyte retrieval

“…The main limitation of our study is that our patient population consisted of favorable prognosis patients; therefore, our findings cannot be necessarily, extrapolated to a more adversely selected patient population with diminished ovarian reserve. Post-operative pain and blood loss were not evaluated in this study since these parameters have been found to decrease with decreasing needle diameter [7,8,12]. A larger randomized study including poor prognosis patients would be helpful to determine whether a specific subgroup of patients would benefit from routine use of the small diameter needles.…”

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