Postgraduate Training Course in Reproductive Health/Chronic Disease

Current evidence on infertility treatment

Review prepared for the 12th Postgraduate Course in Reproductive Medicine and Biology, Geneva, Switzerland

M.A.M. Abdel-Aleem
Assistant Lecturer, OB&GYN Dept
Assiut University Hospital
Assiut, Egypt

See also presentation

Abstract

Infertility is a problem for many couples wishing to conceive. It is estimated that one in 6-7 couples seeks medical advice for an infertility problem. The increased demand for treatment may be due to the increased public awareness of and greater expectations about new treatments. Different treatments in use may not have been evaluated thoroughly (e.g. in randomized clinical trials). The aim of this review is to assess the evidence of different infertility treatments. Medline was searched for randomized controlled trials (RCTs) and systematic reviews between 1997-2003. Also, the Cochrane library issue 1, 2003 was searched. The effectiveness of various treatments is reported. Conclusion: few lines of infertility treatments have been evaluated in either systematic reviews or in well-designed RCTs . For the rest of the treatment options the evidence is unclear.

Introduction

Infertility is generally defined as the state in which a couple cannot conceive after 12 month of unprotected intercourse (1,2) . This is taken as being abnormal as 90% of couples will conceive during that time (3). The cause of infertility is either primary (no pregnancy has ever occurred), or secondary (there has been a pregnancy, regardless of the outcome (2). Primary infertility represents nearly two thirds of the cases while the remaining one third constitutes patients with secondary infertility (4). Idiopathic or unexplained infertility means there has been no definite cause of infertility identified. This ranges between 8%–28% of the infertile population, depending on the strictness of the criteria used for the definition (5,6). Delay in childbearing and the adverse effect of increasing age on women's fertility have increased referrals for fertility investigations and treatments (7). One in six to seven couples require referral for investigation or treatment for sub-fertility (8,9). In general, the exact incidence of the various factors causing infertility varies among different populations and cannot be precisely determined. The main causes of female infertility are ovulation disorders (32%) and tubal damage (26%), and of male infertility oligo-terato-asthenozoospermia (21%), asthenozoospermia (17%), teratozoospermia (10%) and azoospermia (9%). Infertility may be caused by disorders in both male and female partners together in 39% of cases. Female infertility accounts for one-third of all cases and man infertility for one-fifth (4).
Treatments for subfertility have evolved from a plethora of largely unsubstantiated diagnostic tests and empirical treatments into an advanced set of clinical diagnostic tests, allowing identification of subsets of subfertility and their treatments. Appropriate effective therapies are available, but many of them deserve further scientific evaluation (10). There has been no general increase in the prevalence of infertility and the increase in the demand for treatment appears to have been generated by greater expectations (4,11). This in turn has been partly generated by the increased media focus on the new medical procedures and technologies available (12). Natural human fertility is low compared with most other species. The average monthly fecundity rate is only 20% and it is unrealistic to expect a higher chance of pregnancy than this from any fertility treatment (13). The role of the physician is to provide the couple with accurate information leading either to effective therapy or at least a situation that permits the great majority of couples to define an end to a given approach. Armed with accurate information, the physician together wit the couple should be able to establish the goals and probabilities of success of any treatment, the period of time during which pregnancy should occur and the end points when conception is no longer likely to occur (14).
There are four cornerstones to provide patients the accurate information about their problem and the available treatments and have to be discussed with the couple before starting any treatment (14) :

• The factor causing infertility must occur more frequently in an infertile than a fertile population.
• Intervention treatment must produce more pregnancies than expectant treatment.
• The probabilities of success should be known.
• The realistic maximum treatment to conception interval must be known.

Methods

This review aims at assessing the evidence of different methods of infertility treatment by looking for systematic reviews and randomized controlled trials (RCTs) involving any aspect of infertility treatment. These were obtained by searching :

1. The Cochrane library , issue 1,2003.
2. The Medline electronic database was searched using Ovid software (1997 to 2003)

The following search strategy was used :

1. Infertility treatment.
2. Subfertility treatment.
3. Randomized controlled trial (RCT).
4. Controlled clinical trial
5. Randomized controlled trials (RCTs).
6. Meta-analysis.

The identified studies were then evaluated according to the guidelines adapted from "How to use an article about therapy or prevention" for the following criteria (15) :

1. Appropriateness of the study question and study design to answer this question.
2. Duration, timing and location of the study.
3. Randomization procedure.
4. Presence or absence of blinding to treatment allocation.
5. The presence of a statistical power calculation.
6. Number of participants randomized, excluded or lost to follow-  up.
7. Were the participants in all groups followed up and data collected in the same way ?
8. How the results are presented and what is the main result.
9. How the precise results are presented; is the confidence interval is reported?
10. Importance and application of the results.

Results

The search retrieved 70 Cochrane reviews and 109 systematic reviews; meta-analysis and RCTs through the Medline search.
For the Cochrane reviews ; 34 reviews were found to be related to this overview.
The Medline search resulted in 109 articles. Only 14 trials were eligible. Seven studies could not be retrieved. The results are presented in table 1.
Cochrane reviews : the 34 reviews are presented in table 1.

Table 1: Characteristics of relevant studies.

	Number of reviews in Cochrane library (n=34)	Number of eligible Medline studies (n=14  )
Male infertility	1	2
Female infertility   ovulatory factor   tubal/ pelvic factor   endometrial factor   cervical factor	17 9 8 0 0	1 1 0 0 0
Unexplained infertility	5	0
Intrauterine insemination	3	3
ART	8	8

Male infertility

Varicocele is the most frequent physical finding in infertile men (16). It may lead to testicular and epididymal damage via hypoxia and stasis, increased testicular pressure, elevated spermatic vein catecholamines and increased testicular temperature (17,18). Despite the common practice of varicocelectomy for many years, evidence of treatment efficacy was based mainly one non-randomized uncontrolled trial (19). There is no evidence that treatment of varicocele (by either surgery or embolisation) in men from couples with otherwise unexplained infertility will improve the couples’ spontaneous pregnancy chances (20). If varicocelectomy is indicated, the subinguinal approach disclosed a more prominent improvement in both semen concentration and motility in the 6- and 12-month follow-up evaluation when compared to either retroperitoneal, inguinal or percutaneous venous embolisation approaches. Furthermore, due to its simplicity and avoidance of opening the external oblique fascia, it may represent the more plausible approach (21).
Total normal sperm count increases after combined zinc sulfate and folic acid treatment in both subfertile and fertile men. Although the beneficial effect on fertility remains to be established, this finding opens avenues of future fertility research and treatment and may affect public health (22).

Female infertility

Polycystic Ovarian Syndrome (PCOS)

It is a syndrome characterized by chronic anovulation and hyperandrogenism and affects approximately 5% to 10% of women of reproductive age (23). It is probably the most prevalent endocrinopathy in women and by far the most common cause of anovulatory infertility being associated with 75% of cases with anovulatory infertility (24). The development of various types of ovulation induction agents; clomiphene citrate (CC), human menopausal gonadotrophins (hMG), follicle stimulating hormone (FSH) whether urinary or recombinant together with laparoscopic ovarian drilling over the last several decades have been a major advantage in the management of PCOS induced infertility. Treatment options and their outcomes are summarized in table 2.

Table 2 : Evidence of treatments for PCOS.

Intervention	Decision/ evidence	Reference
Clomiphene citrate 50-150   mg/ day	An effective method of inducing ovulation and improving fertility in oligo-ovulatory women. There is a risk  of ovarian cancer.	25
Gonadtrophin therapy	Unclear evidence about the effectiveness as the studies are lacking the sufficient  power. Urinary-derived  FSH  preparations did not improve pregnancy rates when compared to the traditional and cheaper hMG  preparations. The  benefit is  reduction in the risk of OHSS in cycles when administered without the concomitant  use of GnRH analogues. Neither rFSH nor uFSH is preferable to each other when used.	26,27
GnRH analogues as an adjuvant therapy	Ineffective. In addition to the risks of using GnRHa , so this shouldn't be recommended as a standard treatment for patients with PCOS.	28
Metformin	It is difficult make a decision  from currently available research. The addition of metformin to CC results in an improved ovulation and pregnancy rate in both CC-resistant PCOS women. In obese PCOS patients it  improves both restoration of regular menses and spontaneous ovulation, but there are no data supporting an improvement in pregnancy rate.	29
Pulsatile GnRH	Insufficient evidence for its use because of lack of sufficient power of  the 4 studies addressing its use.	30
Ovarian drilling	Insufficient evidence of a difference in cumulative ongoing pregnancy rates between laparoscopic ovarian drilling after 6-12 months follow up and 3-6 cycles of ovulation induction with gonadotrophins as a primary treatment.   Multiple pregnancy rate is considerably reduced in women who conceive following laparoscopic drilling.	31

Endometriosis

It is one of the most frequently encountered benign diseases in gynecology. It is the cause for pelvic pain and infertility in more than 35% of women of reproductive age (32). Complete resolution of endometriosis is not yet possible, but therapy has essentially three main objectives (33) : to reduce pain, to increase the possibility of pregnancy and to delay recurrence for as long as possible. Both medical and surgical treatments are available for this disease. The following points address the evidence of effectiveness of each of these treatments :

• Laparoscopic surgery : the use of laparoscopic surgery in the treatment of minimal and mild endometriosis may improve the success rates. This conclusion is cautiously taken because of methodological problems in the design of the 2 RCTs included in the systematic review (34).
• Ovulation suppression : using danazol, MPA, gestrinone, combined oral contraceptives (CoCs), gonadotrophin releasing hormone analogues (GnRHa). This treatment should not be the standard treatment because of lack of evidence of benefit and the presence of side effects (35).
• Prolonged use of GnRH agonists before in-vitro fertilization- embryo transfer (IVF-ET) in patients with endometriosis resulted in significantly higher ongoing pregnancy rates than did standard controlled ovarian hyperstimulation regimens. No deleterious effect on ovarian response was observed (36).

Tuboplasty and adhesiolysis

There is a high risk of pelvic adhesions after surgery. Any uterine , tubal or ovarian surgery can lead to the formation of adhesions , ovarian failure and tubal dysfunction with subsequent infertility (37). Adhesions may be due to ischemia associated with suturing (38). Adhesion reformation continues to be of concern and appears to be related more to the disease or the patient than to the technique used (37). Four systematic reviews in the Cochrane library were found dealing with this issue :

• Use of fluid agents for preventing adhesions : there is no evidence of benefit if used (39). Further trials are needed to justify the use of steroids.
• Use of barrier agents to prevent postoperative adhesions : although there is evidence that barrier agents reduce the incidence of adhesion formation, there is no evidence to support its use to improve pregnancy rates. Goretex is superior to Interceed but it needs suturing and later removal. There is no evidence of effectiveness of Seprafilm in preventing adhesion formation (40).
• During adhesiolysis, whether by laparoscopy or laparotomy, the following conclusions were made :
  • From randomized controlled trials :
    • No benefit of using operating microscope over loupe.
    • No benefit of using laser in terms of better pregnancy rate.
  • From non-randomized trials :
    • The treatment of adhesions by adhesiolysis appears to improve the possibility of conception.
    • The results are better with magnification rather than without.
    • Laparoscopic salpingostomy appears to be less effective compared to open surgery.
    • Laparoscopic adhesiolysis may be as effective as microsurgical adhesiolysis.
• No evidence on the  use of hydrotubation as a routine following pelvic reconstructive surgery (42).

Unexplained infertility

• Use of clomiphene citrate appears to be a sensible first choice in these cases despite the small treatment effect. This is due to the low cost and the ease of administration (43).
• Use of danazol: there is not enough evidence to support its use in addition to the special precautions regarding its use : cost, side effects and the need for contraception (44).
• Use of bromocriptine : there is no evidence to support its use in unexplained infertility however, it may be used in women with galactorrhea (45).
• There is insufficient evidence of injectable ovulation induction agents being superior to oral drugs. The sample sizes of the included studies addressing this problem are too small (46).
• IVF as a line : although 9 RCTs were found and included in the systematic review, without  reaching  sufficient power to allow firm conclusions. Future studies should  also address adverse effects and costs of the treatments (47).

Intrauterine insemination (IUI)

This is often used for treatment of infertility with various etiologic factors.

• CC is an effective alternative to hMG before intrauterine insemination (48).
• There is a definite advantage for IUI over timed intercourse, both in natural cycles and in cycles with COH (49).
• There is no increase in pregnancy rate per couple if double intrauterine insemination is used instead of single insemination using the partner’s semen (50).
• A 10-minute interval of bed rest after IUI has a positive effect on the pregnancy rate (51).
• A meta-analysis of randomized controlled trials in patients with unexplained infertility showed a significant improvement in pregnancy rates with fallopian sperm perfusion (odds ratio 1.9; 95% confidence interval 1.2-3). It is stated that Fallopian sperm perfusion does not improve the chances of pregnancy in patients with infertility other than those with unexplained infertility. Fallopian sperm perfusion does significantly improve the pregnancy rates of patients with unexplained infertility undergoing controlled ovarian stimulation with gonadotrophin /insemination protocols (52).
• Intrauterine insemination appears to be beneficial when cervical insemination using cryopreserved donor sperm was less successful. However, it is of little benefit where high pregnancy rates have been achieved with cervical insemination. There is no benefit from intrauterine insemination when fresh sperm is used for donor insemination (53).

Assisted reproductive technologies (ART)

The methods of gamete manipulation used in assisted reproductive technology (ART) are rapidly proliferating. The perceived safety and success of ART have led to an increasing demand for its use. Common to all methods of ART are procedures for egg and sperm collection, fertilization in vitro and embryo transfer. Intra-cytoplasmic sperm injection (ICSI) was developed to circumvent the inability of sperm to fertilize an egg. The following tables represent the IVF-ET steps with the corresponding evidences (tables 3, 4, 5, 6).

Table 3 : ART : Controlled Ovarian Hyperstimulation.

Intervention	Decision/evidence		Reference
Pituitary desensitization		Use of GnRH antagonist short protocol  using: it is  short and simple protocol with a significant reduction in incidence of severe OHSS but a lower pregnancy rate compared to the GnRH agonist long protocol.	54
		depot Vs. daily administration of GnRHa : not beneficial	55
Stimulation  regimens		rFSH Vs.  hMG : No difference in clinical pregnancy rate. More large RCTs are needed to estimate the difference between them.	56
		rFSH Vs. uFSH :definite increase in the clinical pregnancy rate with the former.	57
		Highly purified hMG Vs. rFSH: No difference in clinical pregnancy rate; the first is much more costly.	58
		CC + recombinant FSH + recombinant LH Vs. Long protocol: same effectiveness . The former is less expensive, less monitoring, less burden on the patient and the clinic, less risk of OHS.	59
		Use of growth hormone:        **no previous poor response to ovulation induction: No improvement in pregnancy rate       **In poor responders : no evidence.	60
		Use of  R-hCG in the final oocyte maturation: effective, well-tolerated by the patient. 250 ug of R-hCG equals 10000 IU of U- hCG.	61
Prevention of OHS		Intravenous administration of albumin at the time of oocyte retrieval: beneficial	62
		Withholding gonadotrophins ( coasting) :insufficient evidence of effectiveness.	63
		Embryo freezing: insufficient evidence of effectiveness ( only 2 trials were eligible)	64

Table 4 : ART : Sperm manipulations.

Table 5 : ART : Embryo transfer.

Intervention	Decision/evidence	Reference
Stage of transfer	No evidence in favor of either cleavage stage versus blastocyst  transfer	69
Method of transfer	A new Cook Echo-Tip catheter (a new coaxial catheter system with an echo-dense tip) simplifies ultrasound-guided ET, but pregnancy success rates are similar to those obtained when a Wallace catheter is used. There is no statistically significant differences in pregnancy rates whether to leave the catheter or to wait  30 seconds after embryo transfer. It may be due to the fact that waiting interval was insufficient to detect differences, or there is no relation between retention time and the  pregnancy rate	70,71

Table 6 : ART: Luteal phase support.

Intervention	Decision/evidence	Reference
The drug used	Progesterone I.M. Or hCG I.M. :Higher fertility outcomes compared to no treatment. No difference in fertility outcome between them . Progesterone is safer than hCG ( to avoid OHS). Estrogen may be added to progesterone	72

Surgical treatment for tubal disease prior to IVF is an important issue because the presence of hydrosalpinx has been shown to lower the pregnancy rates in IVF cycles. Out of 3 eligible RCTs , it is strongly evident that laparoscopic salpingectomy should be considered for all women with hydrosalpinges prior to IVF treatment. There are 2 issues that need further research : assessment of other surgical options for patients with tubal diseases and the role of surgery in non-hydrosalpinx tubal diseases (73). A meta-analysis performed on 5592 patients (1004 with hydrosalpinx and 4588 with tubal infertility without hydrosalpinx) supports clearly that existing hydrosalpinx during IVF-embryo transfer has negative consequences on the rates of pregnancy, implantation, live delivery and has higher rates of early pregnancy loss. It would be premature, nonetheless, to conclude that routine salpingectomy should be performed on all patients with hydrosalpinx (74).

Discussion

Infertility is a problem for many couples wishing to conceive; for most couples, it means ''failure''. The infertility rate among females has increased over the last 3 decades because of the increasing incidence of PID and STDs. Damaged fallopian tubes are the major causes of infertility and the two organisms ; N. gonorrhea and C. trachomatis are responsible for the majority of cases (1). Also cigarette smoking is becoming more prevalent amongst teenage girls and young adult women: smoking has been shown to be associated with increased risk of infertility due to both an effect on the tubes and on the cervix (12). This could mean that infertility is a semi-preventive health problem.
In the last 60 years, there has been a major advance in the management of infertility but most of the methods used are not based on well-designed studies. The role of the clinician is not only to help to define the couple's problem, but also to be sympathetic and considerate to their emotional state at this most difficult time (12). The results of this overview can be summarized into 3 groups depending on the evidence: Interventions with a good evidence of effectiveness , those with a good evidence of ineffectiveness (that means that they should be abandoned) and a third group with neither (that means that these should be the area of future research).

1. Interventions with good evidence of effectiveness :
   1. Use of clomiphene citrate in PCOS patients.
   2. Use of GnRH antagonists in pituitary desensitization in ART programs.
   3. Use of r-hCG in the final maturation of the oocyte.
   4. Use of intravenous albumin to prevent severe OHS.
   5. Use of ICSI in cases with borderline semen.
   6. Luteal phase support by progesterone.
   7. Use of GnRH in patients with endometriosis before IVF-ET.
2. Interventions with good evidence of ineffectiveness :
   1. Routine varicocelectomy in infertile male patient with varicocele
   2. Use of uFSH or  GnRH in patients with PCOS patients
   3. Use of depot GnRH in pituitary desensitization in ART programmes
   4. Use of growth hormone in ovarian hyperstimulation
   5. Use of ICSI for men with normal semen
   6. Use of danazol or bromocriptine in patients with unexplained infertility
   7. Use of ovulation suppression drugs in women with endometriosis
3. The major group is the third one that includes for example use of GnRH analogues, pulsatile GnRH,  gonadotrophins, metformin and ovarian drilling in the induction of ovulation in patients with PCOS. In addition, in ART programmes, the use of rFSH versus hMG in controlled ovarian hyperstimulation, the prevention of OHS by either coasting or embryo freezing. Also, the following issues deserve exploration: management of  idiopathic abnormal semen parameters and cervical factor infertility.

This overview has disclosed many facts. Firstly, very few treatments have been described either effective or ineffective , while the majority is still in the gray zone. This means that the way is still long in searching the evidence in this particular field. Secondly, poor methodological quality was the major criterion for criticizing the articles, this means that the forthcoming trials should have sound methodology with sufficient sample sizes (e.g. multi-center trials) so not to miss any -even small- differences. Thirdly, the outcome of the ARTs should not be just the clinical pregnancy rate but the rate of single live birth per cycle.
In addition of the importance of the clinical evidence, cost is becoming a more important factor for couples faced with the plethora of therapeutic choices. Therefore infertility treatment options may be dictated by economical considerations rather by the medical effectiveness of the treatments being offered. For example, the evidence in unexplained infertility indicates that IVF as a first -line is not cost effective compared with ovarian stimulation and IUI (75). In order to establish cost-effective care, clinical outcomes under various cost conditions need to be examined. Such a process cannot be static since it has to consider ever evolving treatments and outcome results (76). Infertile couples would probably increase their uptake of IVF services if they are more economic (77).
The emotional aspect isn't to be overlooked but instead, should be an integral part in the management of those patients. An enormous effort is still needed to provide the infertile couples with the best evidence.

Bibliography

1. Mueller BA, Daling JR. Epidemiology of infertility. Extent of the problem, risk factors and associated social changes . In : Controversies in Reproductive Endocrinology and Infertility. Ed. Souls MR. 1989; 1-13. Elsevier, New York.
2. Thonneau P, Marchand S, Tallec A, Ferial ML, Ducot B, Lansac J, Lopes P, Tabaste JM, Spira A. Incidence and main causes of infertility in a resident population (1,850,000) of three French regions (1988-1989). Hum Reprod. 1991 Jul;6(6):811-6. [PubMed]
3. Tietze C. Fertility after discontinuation of intrauterine and oral contraception. Int J Fertil. 1968 Oct-Dec;13(4):385-9. [PubMed]
4. Templeton A, Fraser C, Thompson B. Infertility--epidemiology and referral practice. Hum Reprod. 1991 Nov;6(10):1391-4. [PubMed]
5. Snick HK, Snick TS, Evers JL, Collins JA. The spontaneous pregnancy prognosis in untreated subfertile couples: the Walcheren primary care study. Hum Reprod. 1997 Jul;12(7):1582-8. [PubMed]
6. Collins JA, Burrows EA, Wilan AR. The prognosis for live birth among untreated infertile couples. Fertil Steril. 1995 Jul;64(1):22-8. [PubMed]
7. Cahill DJ, Wardle PG. Management of infertility. BMJ. 2002 Jul 6;325(7354):28-32. [Free Full Text]
8. Hull MG, Glazener CM, Kelly NJ, Conway DI, Foster PA, Hinton RA, Coulson C, Lambert PA, Watt EM, Desai KM. Population study of causes, treatment, and outcome of infertility. Br Med J (Clin Res Ed). 1985 Dec 14;291(6510):1693-7. [PubMed]
9. Templeton A, Fraser C, Thompson B. The epidemiology of infertility in Aberdeen. BMJ. 1990 Jul 21;301(6744):148-52. [PubMed]
10. Evers JL. Female subfertility. Lancet. 2002 Jul 13;360(9327):151-9. [PubMed]
11. Aral SO, Cates W Jr. The increasing concern with infertility. Why now? JAMA. 1983 Nov 4;250(17):2327-31. [PubMed]
12. Tsaltas J. Introduction. In The subfertility handbook: a clinician's guide. Ed. Kovacs GT. 1997; 1-8.
13. Leridon H, Spira A. Problems in measuring the effectiveness of infertility therapy. Fertil Steril. 1984 Apr;41(4):580-6. [PubMed]
14. Taylor PJ. When is enough enough? Fertil Steril. 1990 Nov;54(5):772-4. [PubMed]
15. Guyatt GH, Sackett DL, Cook DJ. Users' guides to the medical literature. II. How to use an article about therapy or prevention. B. What were the results and will they help me in caring for my patients? Evidence-Based Medicine Working Group. JAMA. 1994 Jan 5;271(1):59-63. [PubMed]
16. World health Organisation. WHO laboratory Manual for Examination of Human Semen and Sperm-Cervical Mucus Interaction. Cambridge University Press. Cambridge, 1992.
17. Sweeney TE, Rozum JS, Gore RW. Alteration of testicular microvascular pressures during venous pressure elevation. Am J Physiol. 1995 Jul;269(1 Pt 2):H37-45. [PubMed]
18. Wright EJ, Young GP, Goldstein M. Reduction in testicular temperature after varicocelectomy in infertile men. Urology. 1997 Aug;50(2):257-9. [PubMed]
19. Marsman JW, Schats R. The subclinical varicocele debate. Hum Reprod. 1994 Jan;9(1):1-8. [PubMed]
20. Evers JLH, Collins JA, Vandekerckhove P. Surgery or embolisation for varicocele in subfertile men (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
21. Barbalias GA, Liatsikos EN, Nikiforidis G, Siablis D. Treatment of varicocele for male infertility: a comparative study evaluating currently used approaches. Eur Urol. 1998;34(5):393-8. [PubMed]
22. Wong WY, Merkus HM, Thomas CM, Menkveld R, Zielhuis GA, Steegers-Theunissen RP. Effects of folic acid and zinc sulfate on male factor subfertility: a double-blind, randomized, placebo-controlled trial. Fertil Steril. 2002 Mar;77(3):491-8. [PubMed]

23. Franks S. Polycystic ovary syndrome. N Engl J Med. 1995 Sep 28;333(13):853-61. [PubMed]

24. Adams J, Polson DW, Franks S. Prevalence of polycystic ovaries in women with anovulation and idiopathic hirsutism. Br Med J (Clin Res Ed). 1986 Aug 9;293(6543):355-9. [PubMed]
25. Hughes E, Collins J, Vandekerckhove P. Clomiphene citrate for ovulation induction in women with oligo-amenorrhoea (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
26. Nugent D, Vandekerckhove P, Hughes E, Arnot M, Lilford R. Gonadotrophin therapy for ovulation induction in subfertility associated with polycystic ovary syndrome (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
27. Bayram N, van Wely M, van der Veen F. Recombinant FSH versus urinary gonadotrophins or recombinant FSH for ovulation induction in subfertility associated with polycystic ovary syndrome (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
28. Hughes E, Collins J, Vandekerckhove P. Gonadotrophin-releasing hormone analogue as an adjunct to gonadotrophin therapy for clomiphene-resistant polycystic ovarian syndrome (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
29. Costello MF, Eden JA. A systematic review of the reproductive system effects of metformin in patients with polycystic ovary syndrome. Fertil Steril. 2003 Jan;79(1):1-13. [PubMed]
30. Bayram N, van Wely M, Vandekerckhove P, Lilford R, van der Veen F. Pulsatile luteinising hormone releasing hormone for ovulation induction in subfertility associated with polycystic ovary syndrome (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
31. Farquhar C, Vandekerckhove P, Lilford R. Laparoscopic "drilling" by diathermy or laser for ovulation induction inanovulatory polycystic ovary syndrome (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
32. Nisolle M, Donnez J. Peritoneal endometriosis, ovarian endometriosis, and adenomyotic nodules of the rectovaginal septum are three different entities. Fertil Steril. 1997 Oct;68(4):585-96. [PubMed]
33. Donnez J, Chantraine F, Nisolle M. The efficacy of medical and surgical treatment of endometriosis-associated infertility: arguments in favour of a medico-surgical aproach. Hum Reprod Update. 2002 Jan-Feb;8(1):89-94. [PubMed]
34. Jacobson TZ, Barlow DH, Koninckx PR, Olive D, Farquhar C. Laparoscopic surgery for subfertility associated with endometriosis (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
35. Hughes E, Fedorkow D, Collins J, Vandekerckhove P. Ovulation suppression for endometriosis (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
36. Surrey ES, Silverberg KM, Surrey MW, Schoolcraft WB. Effect of prolonged gonadotropin-releasing hormone agonist therapy on the outcome of in vitro fertilization-embryo transfer in patients with endometriosis. Fertil Steril. 2002 Oct;78(4):699-704. [PubMed]
37. Brosens I, Gordon A. Treatment of tubal infertility. In: Tubal infertility. 1990; 5.1-5.28.
38. Semm K. Advances in pelviscopic surgery. Prog Clin Biol Res. 1982;112 Pt B:127-49. [PubMed]
39. Watson A, Vandekerckhove P, Lilford R. Liquid and fluid agents for preventing adhesions after surgery for subfertility (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
40. Farquhar C, Vandekerckhove P, Watson A, Vail A, Wiseman D. Barrier agents for preventing adhesions after surgery for subfertility (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
41. Watson A, Vandekerckhove P, Lilford R. Techniques for pelvic surgery in subfertility (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
42. Johnson NP, Watson A. Postoperative procedures for improving fertility following pelvic reproductive surgery (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
43. Hughes E, Collins J, Vandekerckhove P. Clomiphene citrate for unexplained subfertility in women (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
44. Hughes E, Tiffin G, Vandekerckhove P. Danazol for unexplained infertility (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
45. Hughes E, Collins J, Vandekerckhove P. Bromocriptine for unexplained subfertility in women (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
46. Athaullah N, Proctor M, Johnson NP. Oral versus injectable ovulation induction agents for unexplained subfertility (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
47. Pandian Z, Bhattacharya S, Nikolaou D, Vale L, Templeton A. In vitro fertilisation for unexplained subfertility (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
48. Ecochard R, Mathieu C, Royere D, Blache G, Rabilloud M, Czyba JC. A randomized prospective study comparing pregnancy rates after clomiphene citrate and human menopausal gonadotropin before intrauterine insemination. Fertil Steril. 2000 Jan;73(1):90-3. [PubMed]
49. Cohlen BJ, Vandekerckhove P, te Velde ER, Habbema JDF. Timed intercourse versus intra-uterine insemination with or without ovarian hyperstimulation for subfertility in men (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
50. Cantineau AEP, Heineman MJ, Cohlen BJ. Single versus double intrauterine insemination (IUI) in stimulated cycles for subfertile couples (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
51. Saleh A, Tan SL, Biljan MM, Tulandi T. A randomized study of the effect of 10 minutes of bed rest after intrauterine insemination. Fertil Steril. 2000 Sep;74(3):509-11. [PubMed]
52. Trout SW, Kemmann E. Fallopian sperm perfusion versus intrauterine insemination: a randomized controlled trial and metaanalysis of the literature. Fertil Steril. 1999 May;71(5):881-5. [PubMed]
53. O'Brien P, Vandekerckhove P. Intra-uterine versus cervical insemination of donor sperm for subfertility (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
54. Al-Inany H, Aboulghar M. Gonadotrophin-releasing hormone antagonists for assisted conception (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
55. Albuquerque LE, Saconato H, Maciel MC. Depot versus daily administration of gonadotrophin releasing hormone agonist protocols for pituitary desensitization in assisted reproduction (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
56. Van Wely M, Westergaard LG, Bossuyt PMM, Van der Veen F. Human menopausal gonadotropin versus recombinant follicle stimulation hormone for ovarian stimulation in assisted reproductive cycles (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
57. Daya S, Gunby J. Recombinant versus urinary follicle stimulating hormone for ovarian stimulation in assisted reproduction cycles (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
58. Efficacy and safety of highly purified menotropin versus recombinant follicle-stimulating hormone in in vitro fertilization/intracytoplasmic sperm injection cycles: a randomized, comparative trial. Fertil Steril. 2002 Sep;78(3):520-8. [PubMed]
59. Weigert M, Krischker U, Pohl M, Poschalko G, Kindermann C, Feichtinger W. Comparison of stimulation with clomiphene citrate in combination with recombinant follicle-stimulating hormone and recombinant luteinizing hormone to stimulation with a gonadotropin-releasing hormone agonist protocol: a prospective, randomized study. Fertil Steril. 2002 Jul;78(1):34-9. [PubMed]
60. Kotarba D, Kotarba J, Hughes E. Growth hormone for in vitro fertilization (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
61. Chang P, Kenley S, Burns T, Denton G, Currie K, DeVane G, O'Dea L. Recombinant human chorionic gonadotropin (rhCG) in assisted reproductive technology: results of a clinical trial comparing two doses of rhCG (Ovidrel) to urinary hCG (Profasi) for induction of final follicular maturation in in vitro fertilization-embryo transfer. Fertil Steril. 2001 Jul;76(1):67-74. [PubMed]
62. Aboulghar M, Evers J.H, Al-Inany H. Intra-venous albumin for preventing severe ovarian hyperstimulation syndrome (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
63. D'Angelo A, Amso N. “Coasting” ( withholding gonadotrophins) for preventing ovarian hyperstimulation syndrome (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
64. D'Angelo A, Amso N. Embryo freezing for preventing ovarian hyperstimulation syndrome (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
65. Van Peperstraten AM, Proctor ML, Phllipson G, Johnson NP. Techniques for surgical retrieval of sperm prior to ICSI for azospermia (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
66. Kuczynski W, Dhont M, Grygoruk C, Grochowski D, Wolczynski S, Szamatowicz M. The outcome of intracytoplasmic injection of fresh and cryopreserved ejaculated spermatozoa--a prospective randomized study. Hum Reprod. 2001 Oct;16(10):2109-13. [PubMed]
67. Van Rumste MME, Evers JLH, Farquhar CM, Blake DA. Intra-cytoplasmic sperm injection versus conventional techniques for oocyte insemination during in vitro fertilisation in patients with non-male subfertility (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
68. Bhattacharya S, Hamilton MP, Shaaban M, Khalaf Y, Seddler M, Ghobara T, Braude P, Kennedy R, Rutherford A, Hartshorne G, Templeton A. Conventional in-vitro fertilisation versus intracytoplasmic sperm injection for the treatment of non-male-factor infertility: a randomised controlled trial. Lancet. 2001 Jun 30;357(9274):2075-9. [PubMed]
69. Blake D, Proctor M, Johnson N, Olive D. Cleavage stage versus blastocyst stage embryo transfer in assisted conception (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
70. Karande V, Hazlett D, Vietzke M, Gleicher N. A prospective randomized comparison of the Wallace catheter and the Cook Echo-Tip catheter for ultrasound-guided embryo transfer. Fertil Steril. 2002 Apr;77(4):826-30. [PubMed]
71. Martinez F, Coroleu B, Parriego M, Carreras O, Belil I, Parera N, Hereter L, Buxaderas R, Barri PN. Ultrasound-guided embryo transfer: immediate withdrawal of the catheter versus a 30 second wait. Hum Reprod. 2001 May;16(5):871-4. [PubMed]
72. Pritts EA, Atwood AK. Luteal phase support in infertility treatment: a meta-analysis of the randomized trials. Hum Reprod. 2002 Sep;17(9):2287-99. [PubMed]
73. Johnson NP, Mak W, Sowter MC. Surgical treatment for tubal disease in women due to undergo in vitro fertilisation (Cochrane Review). In: The Cochrane Library, Issue 1 2003. Oxford: Update Software. [Abstract]
74. Camus E, Poncelet C, Goffinet F, Wainer B, Merlet F, Nisand I, Philippe HJ. Pregnancy rates after in-vitro fertilization in cases of tubal infertility with and without hydrosalpinx: a meta-analysis of published comparative studies. Hum Reprod. 1999 May;14(5):1243-9.  [PubMed]
75. Daya S. Cost-effective, evidence-based infertility care. Curr Opin Obstet Gynecol. 2000 Jun;12(3):227-31. [PubMed]
76. Gleicher N. Cost-effective infertility care. Hum Reprod Update. 2000 Mar-Apr;6(2):190-9. [PubMed]
77. Dyer SJ. The conflict between effective and affordable health care--a perspective from the developing world. Hum Reprod. 2002 Jul;17(7):1680-3.  [PubMed]