RBMOnline - Vol 6. No 4. 439 443 Reproductive BioMedicine Online; www.rbmonline.com/article/872 on web 7 April 2003 Article Conception rates following assisted reproduction in poor responder patients: a retrospective study in 300 consecutive cycles Professor Mustafa Bahceci is currently the Chairman of Department of Obstetrics and Gynecology at Yeditepe University, Istanbul. He completed his Obstetrics and Gynaecology residency in Ankara University, School of Medicine, Turkey in 1984 where he also received his MD degree. He continued to be a Faculty member and was actively involved in development of the reproductive endocrinology department. He underwent postgraduate training in reproductive endocrinology and endoscopic surgery in USA. He then moved to Istanbul and founded the German Hospital IVF unit in 1996, which is now one of the largest centres in the country treating more than 2000 cases a year. One of his major interests is the treatment of advanced endometriosis with endoscopic surgery. Dr Mustafa Bahceci Ulun Ulug 1, Izhar Ben-Shlomo 2, Ersadik Turan 1, Halit Firat Erden 1, Mehmet Ali Akman 1, Mustafa Bahceci 1,3 1 Bahceci Women Health Care Centre and German Hospital at Istanbul 2 Department of Obstetrics and Gynecology, HaEmek Medical Centre, Afula and the Rappaport Faculty of Medicine, Technion Israel Institute of Technology, Haifa, Israel 3 Correspondence: e-mail: mbahceci@hotnail.com Abstract Poor response to ovarian stimulation for assisted reproduction treatment is a therapeutic challenge. Oocyte donation may be unacceptable to some patients, and many couples opt to continue with treatment despite low follicle numbers. Minimal data are available regarding conception rates in poor responders who elect to undergo oocyte retrieval. This study summarizes the outcome of assisted reproduction treatment in poor responders who produced four or fewer oocytes during ovarian stimulation, in order to provide better counselling to such patients in the future. Embryo transfers were performed in 208 of 300 cycles demonstrating poor ovarian response. Pregnancy rate (PR) (15.9%) was significantly higher in patients in whom four oocytes were retrieved, compared with patients in whom one or two oocytes were retrieved (2.3 and 4.3% respectively). Younger patients ( 34 years) had significantly higher PR (19.5%) compared with older patients ( 35 and 39 years, PR 7.2% and 40 years, PR 1.5% respectively). One hundred and twenty-six age-matched normal responders in whom three embryos were transferred had higher implantation rates (15.3%) and PR (37.3%) compared with poor responders in whom three embryos were transferred (6.6 and 16.6% respectively; P < 0.05). In this regard, patient age, number of oocytes retrieved and number of embryos available for transfer determine prognosis for the success of IVF in patients who respond to ovarian stimulation with four or fewer follicles for assisted reproduction treatment. Keywords: IVF, poor responder, ovarian stimulation, pregnancy rate Introduction Poor response to ovarian stimulation for assisted reproductive treatment is a therapeutic challenge. Over the years, several protocols have been suggested to tackle this problem (Padilla et al., 1996; Battaglia et al., 1999; Akman et al., 2000; Kotarba et al., 2003; Kovacs et al., 2001; Lisi et al., 2001; Wang et al., 2002). None of these has proved superior to the others (Mahutte and Arici, 2002), and many were methodologically deficient, generally failing to consider natural inter-cycle variability in the same patient (Surrey et al., 2000; Feldman et al., 2001). The popular trend of delaying first pregnancies is expected to increase the proportion of poor responders. The option of oocyte donation is unavailable, legally banned or religiously unacceptable in some states and cultures. When financial and psychosocial factors are added to this, the situation of poor ovarian response becomes extremely challenging (Collins, 2002). The course of treatment often reaches a point where the dilemma of whether to cancel a cycle or carry on is crucial to save the couple unnecessary financial and emotional burden. Minimal data are available regarding conception rates in poor responders who elect to undergo oocyte retrieval. Since oocyte donation is unacceptable to patients in the present study population, many couples opt to continue despite low follicle numbers. This study summarizes the outcome of assisted reproduction treatment in these poor responders. 439
Materials and methods Patients All assisted reproduction treatment cycles at the German Hospital at Istanbul from January 1997 through January 2000 were searched for patients in whom four or fewer follicles larger than 10 mm at the final phase of ovarian stimulation were seen. Cycles in which five or more oocytes were retrieved were excluded. Out of 3707 cycles, 300 (8%) conformed to the selection criteria. Ten couples opted to cancel oocyte retrieval. From the 290 who underwent the procedure, 208 (72%) underwent embryo transfer. Of the remaining 82 cycles, in 10% no oocytes were retrieved, 65% failed to fertilize and in 25% the zygotes failed to cleave. The cycles were analysed by number of oocytes retrieved, patient s age, and number of embryos transferred. Protocols Two types of ovarian stimulation protocols were employed. The first ( long protocol ) stimulation began with pituitary desensitization using a gonadotrophin-releasing hormone (GnRH) agonist (Lucrin; Abbot, France) in the mid-luteal phase of the preceding menstrual period. Administration of gonadotrophins (Metrodin HP, 75 IU; Serono, Aubonne, Switzerland or Humegon, 75 IU; Organon, Oss, Netherlands) was initiated on day 3 of the commencing cycle. The second ( short protocol ) began with low dose oral contraceptive (Desolett ; Organon) starting on cycle day 1 of the previous cycle for 21 days. On the second day of menstruation, leuprolide acetate (Lucrin ; Abbott) (40 µg s.c. per day) was initiated on cycle day 2, followed by gonadotrophins administered on cycle day 3. In both protocols, gonadotrophin dosage was tailored according to individual ovarian response. The initial doses ranged in the group of low responders from 300 to 450 IU daily. When the leading follicle reached a diameter of 18 mm, human chorionic gonadotrophin (HCG) (Pregnyl ; Organon) 10,000 IU was administered to trigger ovulation. Oocytes were retrieved 35 h following HCG injection and subjected to intracytoplasmic sperm injection (ICSI). Embryos were transferred 48 72 h post-retrieval, transcervically under ultrasound guidance. Luteal phase was supported by 100 mg/day progesterone i.m. in oil. Clinical pregnancy was defined by the ultrasonographic demonstration of a gestational sac and fetal heart beat. Statistical analysis Statistical analysis used analysis of variance (ANOVA) through Bonferroni post-hoc test and chi-squared test, as applicable. A probability value less than 0.05 was considered significant. Results The mean age of the poor responder group was 37.4 (±4.1 SD) years. The mean baseline FSH was 11.34 (±9.3 SD) miu/ml. The mean number of follicules larger than 10 mm on ultrasonography before HCG was 3.02 (±0.9 SD) and the mean number of oocytes was 2.47 (±1 SD). The mean number of embryos transferred was 1.62 (±0.7 SD), with a clinical pregnancy rate (PR) of 8.1% (17/208). There were three (17%) miscarriages through week 20 of pregnancy. There were 11 (5.2%) biochemical pregnancies. Overall delivery rates per oocyte retrieved cycle and embryo transferred cycle were 4.8 and 6.7% respectively. Table 1 shows the breakdown of patient characteristics by the number of oocytes retrieved. There was no difference in age, baseline FSH and oestradiol and amount of gonadotrophin administered. The fertilization rates and the grade composition of transferred embryos did not differ between subgroups. Peak oestradiol concentration was significantly higher when four oocytes were retrieved than when one or two oocytes were Table 1. Breakdown of outcome by number of oocytes retrieved in a group of poor responder women undergoing ovarian stimulation and ICSI embryo transfer. Values are means ± SEM. Single oocyte Two oocytes Three oocytes Four oocytes (n = 43) (n = 69) (n = 52) (n = 44) Age (years) 37.88 ± 0.55 37.46 ± 0.46 37.63 ± 0.54 36.6 ± 0.55 Baseline FSH (miu/ml) 13.95 ± 1.56 12.61 ± 2.27 9.63 ± 0.82 8.77 ± 0.93 No. gonadotrophin 55.63 ± 2.57 63.61 ± 2.58 66.13 ± 3.67 67.53 ± 3.71 ampoules (75 IU each) Oestradiol concentration 549.7 ± 81.8 a,d 703.6 ± 58.3 a 867.4 ± 70.2 b,c 998.0 ± 78.3 b on HCG day (pg/ml) MII/total oocyte (%) 97.6 a 83.3 b 83.9 b 79.3 b Fertilization rate e (%) 100 83.4 82.4 77.4 Grade I II embryo ratio (%) 76.7 87.9 77 81.7 No. embryos transferred 1 a 1.3 ± 0.05 b 1.9 ± 0.1 c 2.2 ± 0.1 c Implantation rate (%) 2.3 3.3 6.8 7.1 Pregnancy rate 1 3 6 7 Pregnancy rate per embryo 2.3 a 4.3 b 11.5 c 15.9 b,c transfer (%) 440 a d Values within rows followed by different superscript letters are significantly different (P < 0.05) e Single oocyte group was not considered in comparison.
Table 2. Breakdown of outcome by age groups in a group of poor responder women undergoing ovarian stimulation and ICSI embryo transfer. Values are means ± SEM. 34 years (n = 46) 35 and 39 years (n = 98) 40 years (n = 65) Age (years) 31.5 ± 0.3 a 37.24 ± 0.1 a 41.78 ± 0.2 a Total oocytes 2.41 ± 0.1 2.59 ± 0.1 2.32 ± 0.1 MII/total oocyte ratio (%) 90.9 84.5 84.5 No. ampoules 64.6 ± 3.6 62.2 ± 2.3 64.1 ± 2.8 Peak oestradiol concentration 826.5 ± 84 802.9 ± 55.9 687.3 ± 69.5 Grade I II embryo ratio (%) 78.3 83 88 No. embryos transferred 1.7 ± 0.19 1.6 ± 0.07 1.54 ± 0.09 Fertilization rate (%) 86.1 81.6 80.9 Implantation rate (%) 13.5 b 5.06 d 1 c Pregnancy rate (%) 19.5 b 7.21 d 1.5 c a Values are significantly different from each other (P < 0.001). b d Values within rows followed by different superscript letters are significantly different (b versus c, P = 0.001; b versus d, P = 0.01; c versus d, P = 0.04). Table 3. Breakdown of outcome by number of embryos transferred in a group of poor responder women who underwent ICSI embryo transfer, compared with age-matched contemporary normal responders who had three embryos transferred. Values are means ± SEM. One embryo Two embryos Three embryos Controls a (n = 109) (n = 69) (n = 30) (n = 126) Age (years) 37.89 ± 0.41 37.35 ± 0.46 36.67 ± 0.57 36.97 ± 0.14 Baseline FSH 12.19 ± 1.04 b 10.3 ± 2.1 10.51 ± 0.98 8.27 ± 0.36 c Peak oestradiol concentration 370.4 ± 35.4 b 823.7 ± 44.3 b,c 1160.2 ± 100.3 c 1860.1 ± 109.1 d Grade I II embryo ratio 81.3 78.7 77 71.9 Implantation rate (%) 3.6 5.07 6.6 15.3 Pregnancy rate (%) 3.6 b,f 10.1 b 16.6 d,g 37.3 c,e a Age-matched controls who had three embryos transferred. b g Values within rows followed by different superscript letters are significantly different (P < 0.05). retrieved. Oocyte quality (expressed as MII to all oocytes ratio) was higher when a single oocyte was retrieved, compared with the other subgroups. The mean number of embryos did not differ between patients in whom three or four oocytes were retrieved. Although the implantation rates did not differ between the subgroups, PR were higher when three or four oocytes were retrieved. Table 2 shows the outcome by age groups. There was no difference between age groups in total number of oocytes retrieved, oocyte quality, gonadotrophins consumed, peak oestradiol, number of embryos transferred and their grade composition. The implantation rate and PR in younger patients ( 34 years) were significantly higher than in the other age groups. Table 3 groups patients by the number of embryos transferred. For perspective, a control group of contemporary, age-matched normal responders in whom three embryos were transferred has been added. There was no significant difference in patients age between the subgroups. Mean baseline FSH of women in whom one embryo was transferred was higher than that in the control group, but did not differ from the other poor responders in whom two or three embryos were transferred. Peak oestradiol concentrations of all poor responder groups were significantly lower than the age-matched control group. The grade composition of transferred embryos did not differ between poor responders and controls. Implantation and pregnancy rates were higher in age-matched controls compared with poor responders. Patients in whom three embryos were transferred had significantly higher PR compared with those in whom one embryo was transferred (P = 0.006). Discussion The definition of poor responder in assisted reproduction treatment is controversial. Several groups have defined poor responders on the basis of mature oocytes (Lashen et al., 1999; Land et al., 2001), others based their definition on elevated early follicular phase of FSH (Bryzski et al., 1988), and some used peak oestradiol concentrations (Surrey et al., 1998) during ovarian stimulation. The lack of uniformity in the definition is also related to the reliability of studies comparing treatments for poor responders. However, there is no doubt that poor responders would ultimately have fewer embryos to be transferred regardless of peak oestradiol, basal FSH or number of oocytes retrieved. In this study, criteria for poor responder 441
442 patients were defined as the number of observed follicules during ultrasound examination at the end of ovarian stimulation. The follicle diameter was set to 10 mm in order also to cover intermediate follicles, which may give rise to oocytes. In the current study, a total of 512 oocytes were retrieved from poor responder patients and the number of total follicles larger than 14 mm visualized on ultrasound was 458 (89.4%), which suggests that intermediate follicles (between 10 and 14 mm) also contributed oocytes. Therefore, considering the follicle measurement criteria and limiting the number of retrieved oocytes to four, there is no doubt that the patients evaluated in the current study are poor responders. This study did not compare stimulation strategies for poor responders, or try to predict their ovarian reserve. It is simply an attempt to lay a foundation that could guide clinicians who confront poor responders, already undergoing ovarian stimulation by any kind of protocol chosen. Our results with a large number of patients demonstrate that maternal age, number of oocytes retrieved and number of embryos transferred are significant prognostic factors in the outcome of poor responders undergoing assisted reproduction treatment. It is of note that poor responders who had three embryos transferred had significantly lower PR compared withwith age-matched controls with similar number and grade composition of transferred embryos. Conceivably, the diminished IVF outcome in poor responders may be related not only to reduced ovarian reserve, but also to lower oocyte quality, undetectable by light microscopy or embryo development. The frequency of aneuploidy in embryos derived from poor responders may also contribute to their reduced PR (Gianaroli et al., 2000). In this regard, endometrial receptivity can also be taken in account in poor responder patients undergoing ovarian stimulation (van der Gaast et al., 2002). Low PR, from 3.2 to 14%, in poor responders have been reported previously (Jenkins et al., 1991; Dor et al., 1992; Land et al., 2001; Spandorfer et al., 2001). Other studies reported higher PR up to 32% (Faber et al., 1998). However, the mean number of oocytes retrieved was 11.1 and mean number of embryos transferred was 4.1 in the study of Faber et al.. In another study, 27.2% PR was achieved in 22 poor responders, but again the number of retrieved oocytes was more than five and the mean age was about 30 years (Raga et al., 1999). Similarly, Moreno et al. performed ICSI in 52 poor responder patients, defined as yielding six or fewer oocytes, and reported 21.1% PR (Moreno et al., 1998). Hanoch et al. (1998) studied 143 poor responders and grouped patients by oestradiol concentration at the time of HCG injection and age intervals. They observed significantly increased PR (16.2%) at oestradiol concentrations between 500 and 800 pg/ml among women with a mean oocyte retrieval rate of six. Consistent with the present results, PR were higher in women aged 20 30 years (19.3%) than in women 31 years or older (6 6.5%). Surrey and coworkers evaluated 39 embryo transfers performed in poor responders and found 23.8% PR in women with a mean age of 36 years and 16.6% in women with a mean age of 41.3 years (Surrey et al., 1998). The mean number of oocytes retrieved from this cohort varied from 3 to 8. Lashen et al. (1999), unlike the present study, observed a pregnancy rate of 31% in patients who developed one or two follicles, 32% with three follicles and 17% with four follicles. In agreement with the trend in the present study, PR were 23% in women below 35 and 12% in women above 36 years respectively. The differences may be attributed to the fact that Lashen et al. studied patients with normal FSH concentrations, whereas the present study included all poor responders. In addition, Lashen et al. included patients by the number of retrieved oocytes (up to five) whereas this study included patients in whom four or fewer follicles were observed. El-Toukhy and co-workers (2002), who described 762 patients with either elevated early follicular FSH concentrations or three or fewer oocytes, found that young age was not prognostic in patients with reduced ovarian reserve (El- Toukhy et al., 2002). Unlike the present study, the mean number of retrieved oocytes in their study was 7.8, 6.5 and 6.0 from young, intermediate and older patient groups respectively. These numbers define a very different group. In patients aged 40 years or older, a 1.5% PR was observed in the present study, while El-Toukhy et al. reported 9.25%, reflecting again the different inclusion criteria. 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