Vincent M.S. Lee*, Joycelyn S.Y. Wong, Sheila K.E. Loh, Noel K.Y. Leong

Transcription

1 BJOG: an International Journal of Obstetrics and Gynaecology February 2002, Vol. 109, pp Sperm motility in the semen analysis affects the outcome of superovulation intrauterine insemination in the treatment of infertile Asian couples with male factor infertility Vincent M.S. Lee*, Joycelyn S.Y. Wong, Sheila K.E. Loh, Noel K.Y. Leong Objective To ascertain the relationship between the initial and unprocessed sperm parameters and pregnancy rates in SOIUI, for Asian couples with male factor infertility. Design Retrospective study. Setting A large government tertiary-care women s hospital with 15,000 deliveries per year. Population One thousand four hundred and seventy nine couples undergoing 2846 of SOIUI. Methods All couples enrolled in the SOIUI programme were analysed, comparing initial sperm parameters and the post-processed total motile sperm, against pregnancy rates per cycle. Main outcome measures Pregnancy rates in relation to initial sperm parameters and post-processed total motile sperm. Results Ninety-three percent of the couples had male factor infertility. The average normal forms for these men was 14.7%. Overall pregnancy rate was 12.1% per completed SOIUI cycle. We found a significant drop in pregnancy rates if the percentage of motile sperms in the unprocessed sperm sample fell below 30%. We also found that insemination of at least 1 million motile sperm resulted in a significant increase in pregnancy rates. Conclusions We recommend SOIUI as an effective treatment of suitable couples with male infertility, before embarking on IVF. However, if the initial percentage of motile sperm fell below 30%, or if after processing, the total motile sperm count was fewer than 1 million, these couples should consider in vitro fertilisation. INTRODUCTION An infertile Asian couple presenting to the gynaecology clinic will often have an abnormal sperm analysis. A recent study of normal Singapore men, who have fathered children, revealed that a large proportion of them had abnormal sperm morpholog 1. Only 20% had normal sperm morphology as defined by the 1993 WHO criteria. The basis for which the WHO defined the minimum semen parameters is not clear. Over the years, the criteria have been redefined. In the 1940 s a sperm count of /ml, a motility of 75% and 60% normal forms were considered the lower threshold for fertility 2. The recent WHO definition-1993 considers a sperm count of /ml, a motility of 50% and 30% normal forms as the threshold to achieve fertility 3. The latest WHO manual-1999 suggests the same, except that the percentage of normal forms has been left blank, to be decided by individual centres 4. These revisions possibly are a result of several Reproductive Medicine Department, Kandang Kerbau Women s and Children s Hospital, Singapore * Correspondence: Dr V. M. S. Lee, Registrar, Department of Reproductive Medicine, KK Women s and Children s Hospital, 100 Bukit Timah Road, Singapore D RCOG 2002 BJOG: an International Journal of Obstetrics and Gynaecology PII: S (0 2) authors reporting good pregnancy rates below these supposedly minimum parameters for fertility 5. These changes in the WHO definitions suggest that the real minimum semen parameters for fertility has yet to be determined. Couples with so-called poor sperm want to know if they have any chance at all of success with superovulation and intrauterine insemination (SOIUI) which is cheaper and less invasive than assisted reproductive methods 6. However, there is a paucity of data from large studies regarding the relationship between the initial semen parameters (before processing) and success in SOIUI. In addition, there is conflicting evidence as to which parameter affects success most. Dickey et al. 7 suggested that the initial sperm motility and initial total motile sperm count were the parameters most likely to affect pregnancy success in SOIUI. Burr et al. suggested that it was sperm morphology and not the number of total motile sperm that affected fertility most 8. Shulman et al. 9 reported that sperm motility was the major determinant of success, while Brasch et al. 10 suggested that the main factor was total motile sperm count after processing. These studies were based on Western populations and had modest numbers of patients. In the only study based on Asian populations, Ho et al. 11,ina prospective study of 15 Asian women reported that postwash total motile sperm count in pregnant were significantly higher, and might be the determinant for success in SOIUI.

2 116 V.M.S. LEE ET AL. The primary objective of this study was to ascertain the threshold values of initial and unprocessed sperm parameters needed for SOIUI, for Asian couples with male factor infertility. The secondary objective was to determine the minimum number of post-processed total motile sperms needed to achieve satisfactory pregnancy rates in SOIUI. MATERIALS AND METHODS This is a retrospective study involving all patients who registered for SOIUI treatment at the Kandang Kerbau Hospital Reproductive Medicine Department, over a period of 5 years, between January 1994 and December Prior to their inclusion, these patients underwent an infertility evaluation which included a full medical history, physical examination, at least one semen analysis collected after at least 48 hour of abstinence (within 6 months of IUI), documentation of ovulation by serum progesterone levels, diagnostic laparoscopy for demonstration of tubal patency, and hysteroscopy. Semen analysis was performed within 30 minutes of collection. As a measure of consistency, this was performed only by two trained scientists applying the WHO criteria. Motility and morphology was assessed manually through the microscope. Patients were allowed into the programme if they had bilateral patent tubes demonstrated at laparoscopy, at least 1 year of infertility and potential ovulatory function. In addition, the male partners had to have sperm parameters of at least a density of 20 million per millilitre, progressive motility of 50% and percentage normal forms of 5%. However, if their sperm parameters did not meet these criteria, couples were still enrolled if the test post-wash number of motile sperms was at least 1 million. We excluded patients who were older than 40 years, those with more than 10 years of infertility, had tubal disease or bilateral blocked tubes, or those with endometriosis of American Fertility Society Classification (AFS) Grade 4 severity. Couples were grouped according to their identified factors of infertility. Some couples had more than one factor identified. The infertility factors identified in this study were ovulatory disorders, male factor infertility, endometriosis, and unexplained infertility. Ovulatory disorder was defined as anovulation demonstrated by luteal phase serum progesterone levels of less than 30 nmol/ml despite maximum dosage of 200 mg/day of clomiphene citrate (CC), or failure to conceive after 6 ovulatory of CC. Male factor infertility was diagnosed if at least one of the semen parameters was less than WHO s lower limits for fertility. Endometriosis was diagnosed only through laparoscopy. These women underwent controlled ovarian hyperstimulation with CC 50mg per day combined with human menopausal gonadotrophins (hmg) 75 iu per day in the first cycle, or with hmg 150 iu alone per day in second, third and subsequent. Transvaginal ultrasound tracking of follicular sizes was performed daily or every other day beginning on day 8 of the cycle. The dosages of hmg were adjusted upwards if necessary, to achieve adequate follicular response. When there were 2 to 4 follicles measuring 16mm or more in 2 perpendicular dimensions, human chorionic gonadotrophin (hcg) 5000 iu was given intramuscularly for final maturation of the follicle and to promote ovulation. Patients were not given hcg if ovulation occurred spontaneously after stimulation, as detected by urinary LH testing. Intrauterine insemination was performed after the hcg injection. Between 1 January 1994 to 31 December 1996 two IUI were performed at 36 hour and 60 hour after hcg injection. Between 1 January 1997 till the end of the study period, only one IUI was performed, unless the total motile sperm count in the inseminate was less than 1 million, in which case a second IUI was performed the next day. Semen was collected on the same day of the IUI, after 48 hour of abstinence, and prepared using the swim-up or the mini-percoll method. Progestogen support in the luteal phase was given in the form of vaginal pessaries for 17 days after insemination. A urine pregnancy test was performed 17 days after the IUI. Pregnancy was defined by a positive urine pregnancy test and was deemed viable when there was fetal heart activity on ultrasound. Pregnancy rates per cycle were computed and tabulated against the various sperm parameters. Data was entered into Microsoft Access 97 (Microsoft Corporation). Statistical analysis was performed with SPSS for Windows (SPSS Inc) by a trained medical statistician. Fisher s Exact test was used to analyse the statistical significance between pregnancy rates. A P value of <0.05 was considered significant, but where needed, the Bonferroni adjustment was applied to correct the P value to a new significance level. The Standardised Canonical Discriminant Function Coefficient was used to predict the most significant sperm parameters responsible for pregnancy. RESULTS One thousand four hundred and seventy nine patients were included during the 5 years. The average age of the female patient was 31 years and the average duration of infertility was 3.5 years. There were 55 couples who were azoospermic but who were allowed into the programme because they could not afford in vitro fertilisation. The Table 1. Distribution of infertility factors for all patients enrolled. Aetiology of infertility patients (n ¼ 1479)* Percentage (%)* Ovulatory disorders 353 (23.8) Male factor 1378 (93.1) Endometriosis (AFS I III) 409 (27.6) Unexplained 35 (2.4) * As some patients had more than one factor, the total does not tally.

3 SPERM MOTILITY IN THE SEMEN ANALYSIS 117 Table 2. Initial sperm parameters. Sperm parameter (%)* Average sperm density [million/ml] 79.4 Average sperm motility (fast) (%) (47.9) Average normal forms (%) (14.7) No. patients with sperm density <20 [million/ml] [228] 15.4 No. patients with sperm motility <50% No. patients with normal forms <30% * Based on 1479 couples. female partner received IUI from anonymous donor sperms. Their pregnancy rates were analysed separately. Ninety-three percent of couples recruited had male factor infertility (Table 1). The majority (88.4%) of them had normal forms of less than 30%, having an average of only 14.7% normal forms (Table 2). For this subgroup of 1378 couples with male factor infertility, we started Three hundred and ten (11.7%) were cancelled because of understimulation despite administration of 300 iu of hmg, because there was a risk of hyperstimulation or because of ovarian cysts. The remaining 2328 completed superovulation. In 238 that completed superovulation, IUI was not performed for reasons already stated above or when the husband could not provide semen. In these, couples were instructed to have coitus. The remaining 2090 completed SOIUI (Fig. 1). Pregnancy occurred in 254 out of 2090, giving a pregnancy rate (PR) of 12.1% per completed IUI cycle and a PR of 18.4% per patient. Initial sperm motility affected a couple s chances of getting pregnant. Motility of less than 30% on sperm analysis predicted a significantly lower pregnancy rate (Table 3). We analysed the effect of percentage normal forms of sperms in the sperm analysis, on the pregnancy rate (Table 3). We found that teratozoospermia did not significantly affect the pregnancy. Table 3. Relationship of initial sperm parameters to pregnancy rates per cycle. Sperm parameter pregnancies Pregnancy rate per cycle (%) Sperm motility (%) < y ** > Motility unavailable Percentage sperm with normal forms (%) < > Sperm density (10 6 /ml) < > Density unavailable Donor sperm used ** Significant at the corrected P level of significance of The initial sperm density on seminal analysis also did not significantly affect the pregnancy rates in SOIUI (Table 3). After processing, the total number of motile sperm (TMS) was counted. The pregnancy rate was significantly decreased if the number inseminated was below one million (Table 4). There was a certain amount of heterogeneity in the male infertility group. Confounding cofactors of infertility were excluded and couples with pure male infertility were Table 4. Effects of post-processed total number of motile sperm inseminated during IUI, on the pregnancy rates. Total motile sperm (10 6 ) Pregnancy rate pregnancies per cycle (%) < y ** ** > Donor sperm used Fig. 1. Flowchart of patient selection. ** Significant at the corrected P level of significance of

4 118 V.M.S. LEE ET AL. Table 5. After exclusion of infertility cofactors relationship of sperm parameters to corrected pregnancy rates per cycle. Sperm parameter Corrected pregnancy pregnancies rate per cycle (%) Sperm motility (%) < y ** > Motility unavailable Total motile sperm (10 6 ) < y ** ** ** ** > Donor sperm used ** Significant at the corrected P level of significance of (motility) or (total motile sperm). analysed. There were 756 couples so identified and they underwent 1180 SOIUI. This resulted in 145 pregnancies, giving a corrected pregnancy rate of 12.3%. An initial sperm motility of at least 30% was still needed and the TMS still had to be at least 1 million to achieve significant success (Table 5). Using Standardised canonical discriminant function coefficient analysis, the initial sperm motility and the post-processed total motile sperm were found to be predictive of pregnancy. This result was also true after correction for other infertility cofactors. The majority of the pregnancies (97.4%) was achieved in the first three (Table 6). However the difference in pregnancy rate between the first three and subsequent was not statistically significant although there was a decreasing trend after the third cycle. In order to illustrate and minimise the effects of performing repeated on a couple, we studied the pregnancy rates obtained in the first completed cycle only, and compared it against the results already presented earlier which Table 6. Relationship of completed IUI cycle number to pregnancy rate per cycle. Cycle number pregnancies Pregnancy rate per cycle (%) and above y Donor sperm cycle Table 7. Relationship of initial sperm parameters to pregnancy rates per cycle only for the first IUI cycle. Sperm parameter involved repeated (Table 7). There were 963 couples who completed their first, resulting in 125 pregnancies and a first cycle pregnancy rate of 13.0%. In analysing only the first cycle data, it appeared that a higher initial sperm motility of 40% was needed, but this difference was not statistically significant. Similarly, it appeared that the minimum TMS needed was still 1 million, but this again was not statistically significant. DISCUSSION pregnancies in the 1 st cycle 1 st cycle Pregnancy rate (%) Sperm motility (%) < > Motility unavailable Total motile sperm (10 6 ) < > Donor sperm used The WHO classification of normal sperm parameters has been regarded as being too stringent in defining male infertility. With particular reference to the percentage of normal forms, the WHO sets an empirical value of 30% and suggests each laboratory determines its own normal ranges for each variable. As such, in Singapore, Chia et al. 1 studied 243 fertile men s semen and found that the mean percentage of normal forms was 20%. There were no differences between the major Asian races. That would place about 75% of these fertile men in the abnormal category. Even in Western populations, Ombelat et al. 12 found that the mean percentage of normal forms was 12%. In our study, 93.1% of the infertile couples had male infertility, with the 88.4% being due to a low percentage of normal forms. Is the infertility really due to these men with abnormal sperm? While it is not the aim of this study to find out what constitutes normal fertile sperm parameters, we did want to determine the minimum criteria that would affect these couples pregnancy rates in SOIUI. Since its beginnings in the mid-1980 s, the debate regarding SOIUI s efficacy has raged. Initially, authors such as Martinez et al. 13 and Allen et al. 14 showed no

5 SPERM MOTILITY IN THE SEMEN ANALYSIS 119 significant advantage of IUI over timed coitus. More recent and prospective studies by Guzick et al. 15, Francavilla et al. 16 and Kirby et al. 17 have demonstrated favourable results, especially in male infertility. In light of this supportive evidence, SOIUI is now an accepted treatment of male infertility. In our centre, this treatment is offered to infertile couples if they meet the inclusion criteria, as an additional modality of treatment prior to in vitro fertilisation. With a pregnancy rate of 12.1% per cycle, SOIUI is indeed a viable alternative. When we counsel patients for SOIUI, the initial sperm analysis is an important indicator of pregnancy. There is a lack of consensus as to which parameter is the most important factor. Our study suggests that sperm motility in the initial sperm analysis is the significant determining factor along with the post-processed total motile sperm count in the inseminate. SOIUI appears effective when the initial sperm motility is at least 30%, and when the total motile sperm count after processing exceeds 1 million. Our findings in this Asian population concur with those reported by Dickey et al. 7 in Western populations. However, in that study, the authors proposed a threshold level of 5 million inseminated total motile sperm, whereas our results suggest the minimum to be 1 million. When we grouped the couples according to their factors of infertility, we found that several had multiple factors. This heterogeneity could possibly confound the results. However, even after controlling for this, by analysing only couples with pure male infertility, we found that the result was the same. Although most of the pregnancies occurred in the first 3, the difference in pregnancy rates between these and the subsequent did not have sufficient statistical power. This could be due to the markedly fewer number of that were performed beyond the third cycle. Earlier studies by Loh et al. 18 had indicated that repeated beyond the third cycle had a significantly smaller success rate. Multiple treatment may not result in an accurate reflection of the success achieved in SOIUI. This is because background fertility of remaining couples declines as fertile couples are removed from the equation by becoming pregnant. Overall, this results in lower pregnancy rates per cycle. By studying just the first, we may eliminate this bias. In the analysis of first cycle data, there was suggestion that the threshold for sperm motility be set at 40% ( P ¼ 0.015). This however, was not statistically significant if the P value was corrected using the Bonferroni correction for multiple comparisons between levels. Likewise, the TMS needed still appeared to be 1 million ( P ¼ 0.005) but was not significant after correction. Recently, the Bonferroni correction method has been appearing more frequently in medical literature, with its primary role being to introduce a more stringent criterion, when determining statistical significance. This is to correct for the use of multiple statistical tests. Interestingly, this idea has been challenged recently by epidemiologists who view that the corrections are, at best unnecessary and, at worst deleterious to sound statistical inference 19. In this study, if the correction is ignored, the difference in the threshold levels is significant for a P level of In studying male infertility, we concur that there exists much variability in semen quality over time. Week by week sperm quality may differ since the sample was collected. Analysis of pre-wash and pre-iui sperm may solve this problem and it may form the basis of a future study. This study is by no means exhaustive and there is a compelling need for large-scale, randomised and controlled studies, especially in Asian populations. CONCLUSION As most Asian men have poor sperm morphology, they should be reassured that they have a chance of fathering a child with SOIUI. Men who have less than 30% motile sperms on initial analysis appear to have a lower chance of success with SOIUI. Lastly, it seems insemination of at least 1 million sperms is required to obtain a satisfactory pregnancy rate. We suggest that men whose semen parameters fall below these threshold values proceed to assisted reproductive techniques. Acknowledgements The authors wish to express their gratitude to Mr. Chung Hing-Ip, Director of the Research Administrative Unit and Chief Statistician, KK Women s and Children s Hospital, Singapore, for his assistance in preparing this paper. References 1. Chia SE, Tay SK, Lim ST. What constitutes a normal seminal analysis? 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