The pain-relieving effect of electro-acupuncture and conventional medical analgesic methods during oocyte retrieval: a systematic review of randomized controlled trials

Elisabet Stener-Victorin

Department of Obstetrics and Gynaecology and Department of Physiology and Institute of Occupational Therapy and Physiotherapy, Sahlgrenska Academy, Göteborg University, Box 455, SE-405 30 Göteborg, Sweden.Email: elisabet.stener-victorin{at}fhs.gu.se


    Abstract
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
OBJECTIVE: The primary objective of the present review was to determine what pain-relieving effect had been reported for acupuncture and other conscious sedation methods in assisted reproduction therapy since 1990. The secondary objective was to determine pregnancy rates, when possible. METHODS: The data source was the Medline database of the National Library of Medicine covering the period January 1990–January 2004. Bibliographies of relevant publications and review articles were scanned. A systematic review and meta-analyses of randomized, controlled trials comparing the pain-relieving effect of acupuncture and other conscious sedation methods was carried out. RESULTS: Of the 30 trials identified, 12 met the selection criteria for this systematic review and were included in the analysis. Five of the 12 studies reported differences in pain experiences during oocyte aspiration, but it was only possible to group the three trials evaluating the effect of electro-acupuncture (EA). The outcomes of these three studies were homogenous except from maximal and average pain. CONCLUSION: No method could be regarded as being superior to another, and no consensus on which method is optimal for pain relief during oocyte retrieval was found. Low doses of lignocaine can, however, be recommended in paracervical block (PCB) as well as EA without pre-medication. The clinical pregnancy rates appeared to be similar between the studies. Since pain experience varies from individual to individual, the optimal method of conscious sedation may also be individualized.

Key words: acupuncture/analgesia/conscious/oocyte retrieval/pain relief


    Introduction
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Transvaginal ultrasound-guided follicle aspiration is the most common method of oocyte retrieval in assisted reproductive technologies. Pain during oocyte retrieval is caused by the passage of the needle through the vaginal wall and by mechanical stimulation of the ovary. The pain perceived during oocyte retrieval is often likened to the intense pain perceived during menstruation. Oocyte retrieval is usually quick, and the analgesic method used must be both effective and safe. It should be easy to administer and monitor, have a rapid onset, provide an ideal amount of pain relief and allow rapid recovery. In addition, the analgesic method must have no toxic effects on the oocytes and embryos since many agents have been detected in the follicular fluid shortly after administration (Wikland et al., 1990Go; Soussis et al., 1995Go; Christiaens et al., 1999Go; Ben-Shlomo et al., 2000Go).

Surprisingly few reports have evaluated the pain-relieving effect of different analgesic methods during oocyte retrieval. A wide variety of analgesic methods were used, but no clear consensus on the method of choice has been formed. One previous meta-analysis evaluated the effect of general and locoregional anaesthesia on reproductive outcome (Kim et al., 2000Go). In total, four studies were included, and the conclusion was that no anaesthetic technique could be definitively recommended as being most beneficial to the reproductive outcome.

Traditional analgesic methods used for transvaginal oocyte retrieval include local injection as a paracervical block (PCB) (Godoy et al., 1993Go; Corson et al., 1994Go; Ng et al., 1999Go, 2000Go, 2001Go, 2003Go); conscious, i.v. or i.m. administered pharmacological sedation in different forms (Bhattacharya et al., 1997Go; Lok et al., 2002Go); epidural (Martin et al., 1999Go); general anaesthesia (Gonen et al., 1995Go); or in some cases no analgesic at all. Recently, electro-acupuncture (EA)—a pain-relieving method that activates the endogenous opioid system (Andersson and Lundeberg, 1995Go; Han, 2003Go)—was found to induce pain relief similar to that induced by a fast-acting opiate during oocyte retrieval and to have fewer negative side effects (Stener-Victorin et al., 1999Go, 2003Go). The conventional method of administering sedation is physician/nurse-administered sedation (PAS). Another method of administration is patient-controlled sedation (PCS), which allows the patients to determine the amount of drug needed. Both epidural and general anaesthesia require a longer recovery time than conscious sedation and are often associated with nausea and dizziness (Whitwam, 1995Go; Meert, 1996Go). Conscious sedation appears to be the most commonly used method of pain relief for oocyte retrieval and, because this method does not require specialized equipment or the expertise of an anaesthesiologist, it is cost effective. Optimal conscious sedation should leave the patient with few side effects and in no danger of airway compromise, and provide adequate analgesia.

The ultimate goal of IVF treatment, however, is the pregnancy rate. As most couples who undergo IVF suffer great stress and anxiety, and repeated attempts are often necessary before success is achieved, the minimization of pain is a major secondary goal. Pain and stress, including stress responses to anaesthesia, can cause patients great discomfort. The purpose of the current study, therefore, was to review the evidence in all randomized trials that had been published since 1990 and which compared different methods of conscious sedation to determine the pain-relieving effect and, if possible, pregnancy rate.


    Materials and methods
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Trial identification
Published trials were identified and sought by searching on-line databases and scanning the bibliographies of relevant publications and review articles. The Medline database of the National Library of Medicine covering the period January 1990–January 2004 was searched using the medical subject headings (MeSH) ‘analgesia’, ‘pain relief’, ‘oocyte aspiration’, ‘oocyte retrieval’ and ‘egg collection’ and the publication type ‘randomized controlled trial’. The search was performed on titles, abstracts, and key words.

Inclusion criteria
The primary outcome of studies that qualified for inclusion in this review was the pain-relieving effect of different analgesic methods during oocyte retrieval. This systematic review was also limited to trials that randomly allocated their patients to different methods of conscious sedation, which included EA in combination with a PCB; different combinations of i.v. sedatives (midozalam, fentanyl, diazepam, pethidine and alfentanil); different combinations of i.m. sedatives (midazolam or promethazine); PCB alone; or PCB in combination with i.v. or i.m. sedatives. Only trials that assessed pain during oocyte retrieval in conscious patients and that had not needed an anaesthesiologist were included. The primary outcome measure was pain experience during oocyte retrieval. The secondary outcome measure was clinical pregnancy rate per IVF cycle started.

Validity assessment and data analysis
The reviewer process was completed independently. The methodological quality of each trial was assessed using a predetermined scoring system comprising eight criteria (Table I), as described in detail previously (Daya and Gunby, 1999Go). Statistical analyses were performed using the Meta-view program in Review Manager 4.1 (The Cochrane Collaboration). Weighted means differences were calculated for continuous data (pain scores). Mantel–Haenszel odds ratios were calculated for dichotomous data (pregnancy rates). The fixed effects model was used for both data types.


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Table I. Validity criteria used to assess the methodological rigour of relevant trials (Daya and Gunby, 1999Go)

 

    Results
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Trials included (Figure 1)
Of the 30 trials identified, 12 met the selection criteria for this systematic review and were included in the analysis (Ben-Shlomo et al., 1992Go; Godoy et al., 1993Go; Corson et al., 1994Go; Bhattacharya et al., 1997Go; Ng et al., 1999Go, 2000Go, 2003Go; Stener-Victorin et al., 1999Go, 2003Go; Lok et al., 2002Go; Humaidan and Stener-Victorin, 2004Go). The reasons for excluding the other trials were spinal anaesthesia and unconscious sedation (general anaesthesia) requiring the expertise of an anaesthesiologist (Tidmarsh and May, 1998Go; Martin et al., 1999Go; Sehpton et al., 2001Go), review (Feichtinger, 1992Go; Freimanis and Jones, 1992Go; Schenker and Ezra, 1994Go; Bokhari and Pollard, 1998Go; Trout et al., 1998Go), other (Ramswak et al., 1990Go; Silva et al., 1997Go) and no pain assessment available (Robinson et al., 1991Go; Sherry, 1992Go; Tan et al., 1992Go; Cook et al., 1993Go; Botta et al., 1995Go; Soussis et al., 1995Go; Awonuga et al., 1996Go; Dell and Cloote, 1998Go).



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Figure 1. Meta-analysis profile summarizing the trial flow.

 
Validity for methodological rigor
The validity scores for methodological rigour of the 12 trials included are presented in Table II. Most trials have a moderate to high ranking based on the predetermined validity criteria used.


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Table II. Validity score for each trial selected

 
Methodological details
The methodological details for each of the 12 trials that met the selection criteria are listed in Table III. The patient characteristics were similar except for minor differences, and all trials used a visual analogue scale (VAS) for pain assessment except for two: one used a 4-point graded scale and the other a 5-point graded scale (Table III). Godoy et al. (1993)Go and Humaidan and Stener-Victorin (2004)Go used a 10 cm VAS which was multiplied by 10.


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Table III. Details of trials comparing pain intensity during oocyte retrieval in different conscious sedations methods

 
Ratings of pain intensity and pregnancy rate
Table IV shows the ratings of pain intensity during and after oocyte retrieval that were reported in the studies. Five of the 12 studies reported differences in pain experiences during oocyte aspiration (Ben-Shlomo et al., 1992Go; Corson et al., 1994Go; Ng et al., 1999Go; Lok et al., 2002Go; Humaidan and Stener-Victorin., 2004Go). It was only possible to group three of the included studies together (Stener-Victorin et al., 1999Go, 2003Go; Humaidan and Stener-Victorin, 2004Go), because most used different outcome measures. The study by Humaidan and Stener-Victorin was grouped alone since the alfentanil group was also given diazepam, and then all three trials are totalled at the bottom in all figures (Figures 2–5).


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Table IV. Ratings of pain intensity during and after oocyte retrieval in different conscious sedation methods. All ratings were made using a VAS except in Ben-Shlomo et al. (1992) and Corson et al. (1994) who used a five-point graded scale.

 
No significant statistical heterogeneity for average and maximal pain during oocyte retrieval was found in the two studies by Stener-Victorin et al. (1999Go, 2003Go) when separated (Figures 2 and 3). In total, there was a significant statistical heterogeneity regarding both average pain, P=0.0006 (Figure 2), and maximal pain, P=0.002 (Figure 3). As for abdominal pain 1–2 h after oocyte retrieval, the statistical heterogeneity was significant in the two studies by Stener-Victorin et al. (1999Go, 2003Go) when separated (P<0.003), but not when considered together (P<0.06) (Figure 4).



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Figure 2. Average pain, assessed with a visual analogue scale (VAS), during oocyte retrieval when studies comparing electro-acupuncture with alfentanil were grouped together. PCB=paracervical block; WMD=weighted mean differences.

 


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Figure 3. Maximal pain, assessed with a visual analogue scale (VAS), during oocyte retrieval when studies comparing electro-acupuncture with alfentanil or alfentanil and diazepam were grouped together. PCB=paracervical block; WMD=weighted mean differences.

 


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Figure 4. Abdominal pain 1–2 h after oocyte retrieval, assessed with a visual analogue scale (VAS), when studies comparing electro-acupuncture with alfentanil or alfentanil and diazepam were grouped together. PCB=paracervical block; WMD=weighted mean differences.

 
Of the 12 trials, eight reported pregnancy rates per started cycle (Table V). There was no significant statistical heterogeneity in total regarding pregnancy rate in the two studies by Stener-Victorin et al. when separated or when considered together (Stener-Victorin et al., 1999Go, 2003Go; Humaidan and Stener-Victorin, 2004Go) (Figure 5).


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Table V. Pregnancy rate in different conscious sedation methods.

 


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Figure 5. Pregnancy rate when studies comparing electro-acupuncture with alfentanil or alfentanil and diazepam were grouped together. PCB = paracervical block; OR = odds ratio.

 

    Discussion
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
The main outcome of this systematic review of randomized trials comparing the pain-relieving effect of different conscious sedation methods is that pain experienced during oocyte retrieval varies depending on the method used. Regarding mean pain intensity during oocyte retrieval, i.v. midozalam was superior to i.m. meperidine and promethazine (Ben-Shlomo et al., 1992Go), PCB with bupivacaine was superior to PCB with saline or no treatment (Corson et al., 1994Go) and oral diazepam, and i.v. alfentanil in combination with PCB was superior to EA in combination with PCB (Humaidan and Stener-Victorin, 2004Go). Regarding abdominal pain 60–120 min after oocyte retrieval, EA was superior to i.v. alfentanil, in combination with both PCB (Stener-Victorin et al., 2003Go), and i.v. PAS (pethidine and diazepam) was superior to i.v. PCS (propofol and alfentanil) (Lok et al., 2002Go). The clinical pregnancy rates appeared to be similar between the studies.

Methodological features
Publication bias has been known to confound the results of systematic reviews and meta-analyses. To avoid bias, only published trials have been included. The fixed effects model showed in the figures of maximal pain and abdominal pain that there is evidence of statistical heterogeneity. Pooling data by using a fixed effects method may overestimate the precision of the estimate of the outcome in question because no consideration is given to the additional error introduced by heterogeneity.

It is standard to have two or more individuals involved in the selection procedure of articles and abstracting data. In the present study, only one person was involved in the selection procedure and, for that reason, there might be a risk for bias introduced even if great care was taken to avoid such a bias.

Only three of the studies could be grouped together because most used different outcome measures (Stener-Victorin et al., 1999Go, 2003Go; Humaidan and Stener-Victorin, 2004Go). Of these three studies, the study by Humaidan and Stener-Victorin was placed alone since they used pre-medication. These three studies were single blinded since for practical reasons it was impossible to perform double or triple blinding in this clinical situation. Furthermore, a co-intervention was given in all three trials. These are the reasons why these studies received lower validity scores.

Sample size calculations diminish the risk of confounding factors and type II errors. In the present review, eight of the 12 trials showed evidence of prior power calculations (Bhattacharya et al., 1997Go; Ng et al., 1999Go, 2000Go, 2001Go; Lok et al., 2002Go; Stener-Victorin et al., 2003Go; Humaidan and Stener-Victorin, 2004Go). In general, it is difficult to form conclusions on the effectiveness of the interventions from trials with small sample sizes. Lack of an effect can also be a consequence of imprecise measurements.

Intervention and their effectiveness
Few studies examined the same sedation method or the same combination of sedation methods, and it is therefore difficult to draw conclusions from cognate studies. This limitation also restricts data pooling for the purpose of meta-analysis, unless interventions are categorized under broader headings. The sedation methods most frequently evaluated were (i) EA in combination with PCB versus i.v. alfentanil in combination with PCB alone or PCB and oral diazepam (three trials); (ii) i.v. alfentanil in combination with PCB (three trials); and (iii) PCB in combination with pre-medication or PCB alone, but with different substances (six trials). Many studies reported a statistically significant difference for at least one outcome measure, which may be evidence of successful randomization and adequate statistical power. The clinical pregnancy rates reported in the studies were found to be equal. The pain-relieving effect of different conscious sedative methods is discussed below. A combination of PCB and local anaesthetics induced significantly better pain relief than PCB and saline (Corson et al., 1994Go; Ng et al., 1999Go). In addition, when i.v. sedation was compared with i.v. placebo, both in combination with a PCB, the latter group experienced 2.5 times higher pain levels (Ng et al., 2001Go). When different doses of lignocaine have been tested, Ng et al. (2003)Go recommend the use of 50 mg because of lack of improvement in pain relief on higher doses and potential dose-related risks. It can be concluded that a PCB combined with local anaesthetics induces good analgesia, which is enhanced further by i.v. sedation. So far, no negative effect on pregnancy rate has been reported, but a low dose of lignocaine is recommended.

The effect of i.v. PCA was evaluated in two studies and was considered to be as effective as physician-controlled techniques (Bhattacharya et al., 1997Go; Lok et al., 2002Go). Although pain ratings were higher—as were the doses of drugs required—in the patients who controlled their own sedation (PCS) compared with the patients who had their analgesic administered by a physician (PAS), both studies concluded that pain was modest and well tolerated by the patients and that satisfaction levels were high (Bhattacharya et al., 1997Go; Lok et al., 2002Go). However, since PCS demands higher doses of analgesics and many drugs have been found in the follicular fluid shortly after i.v. injection, it is questionable whether this method is optimal in the present situation.

EA in combination with PCB as an analgesic method during oocyte retrieval was evaluated in three studies (Stener-Victorin et al., 1999Go, 2003Go; Humaidan and Stener-Victorin, 2004Go). There was no heterogeneity regarding the pain ratings of EA given 30 min prior to the procedure and alfentanil, both in combination with a PCB (Stener-Victorin et al., 1999Go, 2003Go). When the study by Humaidan and Stener-Victorin (2004)Go, which also focused on pain relief, was included, there was a significant statistical heterogeneity regarding both average and maximal pain. In the study of Humaidan and Stener-Victorin, however, EA was given for only 1–2 min prior to the PCB and the control group received pre-medication. Interestingly, the mean and maximum pain ratings of the EA group in the study of Humaidan and Stener-Victorin are comparable with those in the EA groups of the two previous studies that evaluated the pain-relieving effect of EA (Stener-Victorin et al., 1999Go, 2003Go; Humaidan and Stener-Victorin, 2004Go). The most reasonable explanation for the significant difference in pain ratings reported by Humaidan and Stener-Victorin might be the pre-medication that the patients who received conventional i.v. pharmacological sedation were given. In the two studies by Stener-Victorin et al. (1999Go, 2003Go), no group received pre-medication.

The abdominal pain 2 h after oocyte retrieval was lower in patients who received EA as analgesia compared with alfentanil, both in combination with PCB (Stener-Victorin et al., 1999Go, 2003Go). The use of EA is still in its initial phase of acceptance in modern Western medicine, and the effect of acupuncture relies on a physiological basis (Stener-Victorin et al., 2002aGo). However, the exact impact and significance of different needle location and stimulation frequencies currently are unknown. Further studies are needed to determine the optimal stimulation parameters, e.g. needle location, stimulation frequency and necessity for a pre-treatment, i.e. does EA given 30–45 min before oocyte retrieval induce better pain relief?

Patient satisfaction is another important issue. In the study by Humaidan and Stener-Victorin (2004)Go, 87 of 100 patients in the EA group replied that they would prefer EA as the pain-relieving method during oocyte retrieval if they would return for another IVF cycle. Patients also reported high levels of satisfaction with i.v. opiates administered by a physician or the patient (Bhattacharya et al., 1997Go; Lok et al., 2002Go).

Patient motivation and ability to cope with pain during oocyte retrieval and also support from the medical team is an important component for pain relief in all types of methods. Furthermore, it is well known that the effect of all types of pain relief can be lost if patients feel emotionally unsafe and uncomfortable with the analgesic method. Recent functional neuroimaging studies indicate that expectation, both certain and uncertain, plays an important role in the modulation of both acute and chronic pain, and that expectation is mediated by neural pathways (Ploghaus et al., 2003Go).

Other factors that may influence the pain experienced during oocyte retrieval are body mass index (BMI), duration of oocyte retrieval, number of follicles punctured, follicular flushing and size of the aspiration needle (Ng et al., 1999Go). In addition, the first cycle has been shown to be the most painful (Gohar et al., 1993Go).

Outcome measurements and future direction for research
Nine of the trials in this review used a VAS to assess pain. The VAS traditionally has been used as a method for evaluating the effectiveness of analgesic, but the scale has limitations in quantifying feelings and attitudes of patients, and the accuracy of the VAS is questionable. Even though it may not be the ‘gold standard’ that it once was thought to be, the VAS is certainly a valuable tool for the assessment of pain in this clinical situation. New methods of pain assessment are, however, needed. Electrical stimuli against which the patient can match her perceived pain with non-visualized, pre-determined end-points is an alternative method for evaluating pain that allows a continuous, ordinal, individual response with non-visualized pre-determined lower or upper limits. Perceptual matching has been well accepted by patients during oocyte retrieval without any complications and may therefore be a valuable alternative to VAS in future studies (Stener-Victorin et al., 2002bGo).

Another aspect in pain assessment is when and how the pain ratings are made. Ng et al. (2000)Go rated maximal pain during oocyte retrieval ‘within 4 h’ after oocyte retrieval. The ratings were surprisingly low when compared with those made in their previous studies with a similar study protocol. One possible explanation might be that the pain ratings were made up to 4 h after oocyte retrieval, a time interval that is too long since it is well known that experienced pain should be assessed during or as soon as possible after experienced pain.

For future research, only randomized control trials should be accepted and standardized measurements of outcomes are recommended to facilitate scientific advances. In this review, no study measured pain during oocyte retrieval. In future studies, it should be a goal to assess experienced pain during the procedure. Furthermore, scales used should ask their questions in the same manner. VAS has limitations in assessing pain, and other methods should be introduced, e.g. the McGill Pain questionnaire as a complement to VAS. After the procedure, it can be recommended to rate experienced pain every 30 min for the first 2 h in order to follow the post-operative recovery. Co-interventions should be avoided.

Pregnancy rate
Seven of the trials in this review reported fertilization and pregnancy rates in relation to the different analgesic methods. No other study reported any differences in pregnancy rates between their groups. Heterogeneity was non-significant regarding pregnancy when data from the three studies using EA as a pain relief technique were combined. It is important to keep in mind that most studies comprise too few patients for any conclusions on pregnancy rate to be drawn.

Whether different analgesics per se adversely affect fertilization outcome is unclear. In mice, embryo cleavage was inhibited at concentrations of 10 ng/ml propofol, significant pathogenetic activation was noted at 50 ng/ml, and in vitro maturation was suppressed at 10 000 ng/ml (Alsalili et al., 1997Go). Alfentanil has been found in follicular fluid shortly after i.v. injection (Soussis et al., 1995Go), but there are no data on the fecundability of oocytes during alfentanil administration. Although embryo cleavage characteristics and fertilization in human oocytes were shown to be similar between propofol–alfentanil anaesthesia and PCBs (Christiaens et al., 1999Go) as well as oocytes exposed to propofol (Ben-Shlomo et al., 2000Go), it would be prudent to minimize the amount of anaesthetics delivered. To evaluate whether the anaesthetic method influences the IVF outcome, future studies need to be designed with adequate numbers of patients. Biochemical analyses of follicular fluid and plasma may provide important leads.

The optimal method for evaluating the efficacy of different conscious sedation is to conduct a randomized controlled trial with sufficient power and clear end-points. The data from all the trials in this review were not combined because of differences in how the assessment procedure was reported. In future studies, when and how pain assessment was performed must be well described. Since pain and discomfort are associated with stress and anxiety, pain assessment should be supplemented by questionnaires.

Gaps in knowledge
What effect does conscious sedation—pharmacological and non-pharmacological—have on the embryo and fertilization, on a patient's experiences during oocyte retrieval and on cost–benefits? In future studies, guidelines for pain assessment must be made consistent.

Conclusion
No method could be regarded as being superior to another, and no consensus on which method is optimal for pain relief during oocyte retrieval was found. Low doses of lignocaine can, however, be recommended in PCB, as well as EA without pre-medication for pain relief during oocyte retrieval. Conscious sedation is most appropriate in patients who are willing and cooperative. Thus, most—but not all—patients undergoing IVF are suitable candidates for this type of sedation. As yet there is no consensus on which method is optimal. Since pain experience varies from individual to individual, the optimal method of conscious sedation may also be individual.


    References
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Alsalili M, Thornton S and Fleming S (1997) The effect of the anaesthetic, propofol, on in-vitro oocyte maturation, fertilization and cleavage in mice. Hum Reprod 12, 1271–1274.[CrossRef][ISI][Medline]

Andersson S and Lundeberg T (1995) Acupuncture—from empiricism to science: functional background to acupuncture effects in pain and disease. Med Hypotheses 45, 271–281.[ISI][Medline]

Awonuga A, Waterstone J, Oyesanya O, Curson R, Nargrund G and Parsons J (1996) A prospective randomized study comparing needles of different diameter in transvaginal ultrasound-directed follicle aspiration. Fertil Steril 65, 109–113.[ISI][Medline]

Ben-Shlomo I, Amodai I, Levran D and Dor J (1992) Midazolam–fentanyl sedation in conjunction with local anesthesia during oocyte retrieval for in vitro fertilization. Assist Reprod Genet 9, 83–85.

Ben-Shlomo I, Moskovich R, Golan J, Eyali V, Tabak A and Shalev E (2000) The effect of propofol anaesthesia on oocyte fertilization and early embryo quality. Hum Reprod 15, 2197–2199.[Abstract/Free Full Text]

Bhattacharya S, MacLennan F, Hamilton MP and Templeton A (1997) How effective is patient-controlled analgesia? A randomized comparison of two protocols for pain relief during oocyte recovery. Hum Reprod 12, 1440–1442.[Abstract]

Bokhari A and Pollard BJ (1998) Anaesthesia for assisted conception. Eur J Anaesthesiol 15, 391–396.[CrossRef][ISI][Medline]

Botta G, D'Angelo A, D'Ari G, Merlino G, Chapman M and Grudzinskas G (1995) Epidural anesthesia in an in vitro fertilization and embryo transfer program. J Assist Reprod Genet 12, 187–190.[ISI][Medline]

Christiaens F, Janssenswillen C, Verborgh C, Moerman I, Devroey P, Van Steirteghem A and Camu F (1999) Propofol concentrations in follicular fluid during general anaesthesia for transvaginal oocyte retrieval. Hum Reprod 14, 345–348.[Abstract/Free Full Text]

Cook LB, Lockwood GG, Moore CM and Whitwam JG (1993) True patient-controlled sedation. Anaesthesia 48, 1039–1044.[ISI][Medline]

Corson L, Batzer FR, Gocial B, Kelly M, Gutmann JN, Go KJ and English ME (1994) Is paracervical block anesthesia for oocyte retrieval effective? Fertil Steril 62, 133–136.[ISI][Medline]

Daya S and Gunby J (1999) Recombinant versus urinary follicle stimulation hormone for ovarian stimulation in assisted reproduction. Hum Reprod 14, 2207–2215.[Abstract/Free Full Text]

Dell RG and Cloote AH (1998) Patient controlled sedation during transvaginal oocyte retrieval: an assessment of patient acceptance of patient-controlled sedation using a mixture of propofol and alfentanil. Eur J Anaesthiol 15, 210–215.

Feichtinger W (1992) Current technology of oocyte retrieval. Curr Opin Obstet Gynecol 4, 697–701.[ISI][Medline]

Freimanis MG and Jones AF (1992) Transvaginal ultrasonography. Radiol Clin North Am 30, 955–976.[ISI][Medline]

Godoy H, Erard P, De Munck L, Camus M, Gepts E, Van Steirteghem AC and Devroey P (1993) Comparison of two local anaesthetics in transvaginal ultrasound-guided oocyte retrieval. Hum Reprod 7, 1093–1097.

Gohar J, Lunenfeld E, Potashnik G and Glezerman M (1993) The use of sedation only during oocyte retrieval for in vitro fertilization: patients' pain self-assessments versus doctors' evaluations. J Assist Reprod Genet 12, 678–682.

Gonen O, Shulman A, Gehtler Y, Shapiro A, Judeiken R, Beyth Y and Ben-Nun I (1995) The impact of different types of anesthesia on in vitro fertilization-embryo transfer treatment outcome. J Assist Reprod Genet 12, 678–682.[ISI][Medline]

Han JS (2003) Acupuncture: neuropeptide release produced by electrical stimulation of different frequencies. Trends Neurosci 26, 17–22.[CrossRef][ISI][Medline]

Humaidan P and Stener-Victorin E (2004) Pain relief during oocyte retrieval with a new short duration electro-acupuncture technique—an alternative to conventional analgesic methods. Hum Reprod 19, 1367–1372.[Abstract/Free Full Text]

Kim JL, Kil HK, Koh SO and Kim KI (2000) Effects of general and locoregional anesthesia on reproductive outcome for in vitro fertilization: a meta-analysis. J Korean Med Sci 15, 68–72.[ISI][Medline]

Lok IH, Chan MTV, Chan DLW, Cheung LP, Hains CJ and Yuen PM (2002) A prospective randomized trial comparing patient-controlled sedation using propofol and alfentanil and physician-administered sedation using diazepam and pethidine during transvaginal ultrasound-guided oocyte retrieval. Hum Reprod 17, 2101–2106.[Abstract/Free Full Text]

Martin R, Tsen LC, Tzeng G, Hornstein MD and Datta S (1999) Anesthesia for in vitro fertilization: the addition of fentanyl to 1.5% lidocaine. Anesth Analg 88, 523–526.[Abstract/Free Full Text]

Meert TF (1996) Pharmacotherapy of opioids: present and future developments. Pharm World Sci 18, 1–15.[CrossRef][ISI][Medline]

Ng EH, Tang OS, Chui DK and Ho PC (1999) A prospective, randomized, double-blind and placebo-controlled study to assess the efficacy of paracervical block in the pain relief during egg collection in IVF. Hum Reprod 14, 2783–2787.[Abstract/Free Full Text]

Ng EH, Tang OS, Chui DK and Ho PC (2000) Comparison of two different doses of lignocaine used in paracervical block during oocyte collection in an IVF programme. Hum Reprod 15, 2148.[Abstract/Free Full Text]

Ng EH, Chui DK, Tang OS and Ho PC (2001) Paracervical block with and without conscious sedation: a comparison of the pain levels during egg collection and the post operative side effects. Fertil Steril 75, 711–717.[CrossRef][ISI][Medline]

Ng EH, Miao B and Ho PC (2003) A randomized double-blind study to compare the effectiveness of three different doses of lignocaine used in paracervical block during oocyte retrieval. J Assist Reprod Genet 20, 8–12.[CrossRef][ISI][Medline]

Ploghaus A, Becerra L, Borras C and Borsook D (2003) Neural circuitry underlying pain modulation: expectation, hypnosis, placebo. Trends Cogn Sci 7, 197–200.[CrossRef][ISI][Medline]

Ramswak SS, Kumar A, Welsby R, Mowforth A, Lenton EA and Cook ID (1990) Is analgesia required for transvaginal single-follicle aspiration in in-vitro fertilization: a double-blind study. J In Vitro Fertil Embryo Transf 7, 103–106.[ISI][Medline]

Robinson JN, Forman RG, Lockwood GM et al. (1991) A comparison of the transient hyperprolactinemic stress response obtained using 2 different methods of analgesia for ultrasound-guided transvaginal oocyte retrieval. Hum Reprod. 6, 1291–1293.[Abstract]

Schenker JG and Ezra Y (1994) Complications of assisted reproductive techniques. Fertil Steril 61, 411–422.[ISI][Medline]

Sehpton VC, Shaw A, Cowan CM, Thomas K, Wood S and Barclay PM (2001) Sedation and analgesia for transvaginal oocyte retrieval: an audit resulting in a change of clinical practice. Hum Fertil 4, 94–98.

Sherry E (1992) Admixture of propofol and alfentanil—use for intravenous sedation and analgesia during transvaginal oocyte retrieval. Anaesthesia 47, 477–479.[ISI][Medline]

Silva PD, Sorensen ML and Silva DE (1997) Improving the cost-to-benefit ratio of in-vitro fertilization. Wis Med J 96, 36–39.[Medline]

Soussis I, Boyd O, Paraschos T, Duffy S, Bower S, Troughton P, Lowe J et al. (1995) Follicular fluid levels of midazolam, fentanyl, and alfentanil during transvaginal oocyte retrieval. Fertil Steril 64, 1003–1007.[ISI][Medline]

Stener-Victorin E, Waldenstrom U, Nilsson L, Wikland M and Janson PO (1999) A prospective randomized study of electro-acupuncture versus alfentanil as anaesthesia during oocyte aspiration in in-vitro fertilization. Hum Reprod 14, 2480–2484.[Abstract/Free Full Text]

Stener-Victorin E, Wikland M, Waldenstrom U and Lundeberg T (2002a) Alternative treatments in reproductive medicine: much ado about nothing: acupuncture—a method of treatment in reproductive medicine: lack of evidence of an effect does not equal evidence of the lack of an effect. Hum Reprod 17, 1942–1946.[Abstract/Free Full Text]

Stener-Victorin E, Kowalski J and Lundeberg T (2002b) A new highly reliable instrument for the assessment of pre- and postoperative gynecological pain. Anesth Analg 95, 151–157.[Abstract/Free Full Text]

Stener-Victorin E, Waldenstrom U, Wikland M, Nilsson L, Hagglund L and Lundeberg T (2003) Electro-acupuncture as a peroperative analgesic method and its effects on implantation rate and neuropeptide concentrations in follicular fluid. Hum Reprod 18, 1454–1460.[Abstract/Free Full Text]

Tan SL, Waterstone J, Wren M and Parsons J (1992) A prospective randomized study comparing aspiration only with aspiration on flushing for transvaginal ultrasound-directed oocyte recovery. Fertil Steril 58, 356–360.[ISI][Medline]

Tidmarsh MD and May AE (1998) Spinal analgesia for oocyte retrieval. Int J Obstet Anesth 7, 157–160.[CrossRef][ISI][Medline]

Trout SW, Hazard Vallerand AH and Kemmann E (1998) Conscious sedation for in vitro fertilization. Fertil Steril 69, 799–808.[CrossRef][ISI][Medline]

Whitwam JG (1995) Co-induction of anaesthesia: day-case surgery. Eur J Anaesthesiol Suppl 12, 25–34.[Medline]

Wikland M, Evers H, Jakobsson AH, Sandqvist U and Sjoblom P (1990) The concentration of lidocaine in follicular fluid when used for paracervical block in a human IVF-ET programme. Hum Reprod 5, 920–923.[Abstract]

Submitted on August 18, 2004; resubmitted on September 27, 2004; accepted on October 6, 2004.





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