Article Luteal support with vaginal micronized progesterone gel in assisted reproduction

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1 RBMOnline - Vol 6. No Reproductive BioMedicine Online; on web 29 January 2003 Article Luteal support with vaginal micronized progesterone gel in assisted reproduction Dr Alan Penzias Dr Alan Penzias is an Assistant Professor of Obstetrics, Gynecology, and Reproductive Biology at Harvard Medical School, Associate Director of the Division of Reproductive Endocrinology at Beth Israel Deaconess Medical Centre and an active practitioner at Boston IVF in Waltham, MA. Following a residency in obstetrics and gynaecology at Beth Israel Hospital and Harvard Medical School in Boston, MA, he completed a fellowship in reproductive endocrinology at Yale University School of Medicine under the direction of Dr Alan DeCherney. He has published more than 50 papers and textbook chapters in the field of infertility and has lectured extensively in the USA and abroad. Dr Penzias research interests centre on the patient friendly approach to infertility treatment, removing barriers to care through innovation and outcomes-oriented research. Alan S Penzias 1,2,3, Michael M Alper 1,2 1 Division of Reproductive Endocrinology, Beth Israel Deaconess Medical Centre, Harvard Medical School, Boston, MA, USA; 2 Boston IVF, Waltham, MA, USA 3 Correspondence: alan.penzias@bostonivf.com Abstract The purpose of this study was to review the rationale for vaginal progesterone treatment as luteal support in IVF, and the clinical experience with vaginal micronized progesterone gel. It was found that luteal support with exogenous progesterone significantly improves implantation and pregnancy rates after IVF. Vaginal administration offers a number of potential advantages over intramuscular injection in terms of tolerability and convenience. The clinical experience with Crinone 8%, a vaginal gel containing 90 mg micronized progesterone in a polycarbophil base, indicates that the use of this preparation is associated with pregnancy rates comparable with those achieved after intramuscular administration of progesterone. Moreover, in studies in which patient preferences have been assessed, significantly higher preferences for vaginal micronized progesterone gel have been reported, compared with intramuscular administration or vaginal suppositories. In conclusion, the vaginal micronized progesterone gel used in this study provided effective and well-tolerated luteal support in women undergoing IVF. Keywords: assisted reproduction, Crinone 8%, IVF, luteal support, progesterone, vaginal administration Introduction It has long been recognized that ovarian stimulation during IVF treatment, particularly in cycles incorporating gonadotrophin-releasing hormone agonist (GnRH-a), impairs corpus luteum function and results in luteal phase insufficiency (Smitz et al., 1992b, 1993). In stimulated cycles, the duration of ovarian steroid production is usually 1 3 days shorter than in normal cycles, resulting in a truncated luteal phase (Jones et al., 1986). This has led to concern that inadequate endometrial support in the luteal phase may impede successful implantation. Furthermore, ovarian stimulation results in multiple follicular maturation, and hence in supraphysiological concentrations of oestradiol and progesterone during the early luteal phase. These elevated steroid concentrations may also impair uterine receptivity, even when the length of the luteal phase is adequate; endometrial histology is advanced in the presence of high progesterone concentrations, and excessive responses are associated with reduced implantation rates (Toner et al., 1991, 1993; de Ziegler et al., 1994; Kolb and Paulson, 1997). Furthermore, strong responses to ovarian stimulation can result in increased uterine motility at the time of embryo transfer (Abramowicz and Archer, 1990), and this has been associated with a decreased pregnancy rate (Fanchin et al., 1998). A number of studies have shown that luteal phase support improves outcome after IVF. Early studies showed that treatment with human chorionic gonadotrophin (HCG), which stimulates steroid production in the corpus luteum, resulted in pregnancy rates of between 18.7% and 50%, compared with between 9.3% and 17% in patients who received no luteal support (Smith et al., 1989; Belaisch-Allart et al., 1990; Herman et al., 1990). HCG treatment was, however, associated with an increased risk of ovarian hyperstimulation syndrome (OHSS) (Herman et al., 1990). An alternative approach to luteal support is supplementation with exogenous progesterone. A review of luteal support with exogenous progesterone found that cycle outcomes were equivalent to luteal support with HCG but had a decreased 287

2 288 incidence of OHSS (Penzias, 1995). A meta-analysis of randomized trials of luteal support showed that both HCG and progesterone supplementation produced significantly higher pregnancy rates than did placebo treatment (Soliman et al., 1994), supporting the routine use of such treatment in IVF. Choice of treatment for luteal support One study described treatment with 17α-hydroxyprogesterone (341 mg i.m. every 3 days), beginning within 24 h of embryo transfer, and found a pregnancy rate of 32.5%, compared with 18.3% in placebo-treated patients (Abate et al., 1999). Early trials showed that comparable pregnancy rates were achieved with HCG and either intramuscular or vaginal progesterone (Van Steirteghem et al., 1988; Claman et al., 1992), but the meta-analysis by Soliman et al. (1994) concluded that HCG was more effective than progesterone in providing luteal support during IVF. This analysis, however, may have been biased by the inclusion of one trial in which oral treatment with micronized progesterone was associated with significantly lower implantation and pregnancy rates than HCG (Buvat et al., 1990). Progesterone is extensively metabolized after oral administration (Nahoul et al., 1993), and the circulating concentrations achieved are inadequate to maintain the endometrium (Figure 1) (Levine and Watson, 2000). More recent studies have supported the conclusion that HCG and progesterone provide equivalent luteal support. In one study (Araujo et al., 1994), implantation and pregnancy rates were 12% and 36.7%, respectively, in patients receiving HCG, compared with 14% and 35.3%, respectively, in patients treated with intramuscular progesterone. However, the incidence of moderate or severe OHSS was higher in patients receiving HCG. A second study compared the efficacy of vaginal progesterone, 400 mg/day, alone or in combination with HCG, 1500 IU on days 3, 6, 9 and 12 after oocyte retrieval (Mochtar et al., 1996); OHSS developed in 11 out of Figure 1. Serum progesterone concentrations after vaginal administration of progesterone gel (Crinone 8%), 90 mg, or oral administration of micronized progesterone (prometrium), 100 mg (Nahoul et al., 1993). Concentrations were measured by radioimmunoassay (RIA) or liquid chromatography-mass spectrometry (true). After oral administration, progesterone has a short half-life, and the circulating concentrations achieved are too low to provide adequate endometrial support. 89 cycles with HCG treatment, and hence no further HCG was given after the first dose. There was no significant difference in pregnancy rates between the two regimens. A recent study has compared the efficacy of HCG and vaginal progesterone in 413 patients who were stratified into two OHSS risk groups on the basis of oestradiol concentrations on the day of HCG and the number of oocytes present at oocyte retrieval (Ludwig and Diedrich, 2001). Patients in the highrisk group were randomized to receive progesterone alone or in combination with a single dose of HCG on the day of embryo transfer. Those in the low-risk group were randomized into one of three possible luteal phase treatment arms: (i) progesterone alone; (ii) HCG alone; or (iii) progesterone plus HCG. Patients in arm (i) received 600 mg of progesterone daily starting on the evening before embryo transfer. Patients in arm (ii) received three supplemental doses of HCG of 5000 IU on the day of embryo transfer, 5000 IU 3 days after embryo transfer and 2500 IU 6 days after embryo transfer. Patients in arm (iii) received 600 mg of progesterone daily starting on the day of embryo transfer and also received a single 5000 IU dose of HCG on the day of embryo transfer. There was no significant difference in pregnancy rates between the groups, but the incidence of OHSS was significantly higher in patients in the high-risk group who received HCG. Together, therefore, the available evidence shows that HCG offers no significant advantage over progesterone as luteal support in IVF, and it is associated with an increased risk of OHSS. Options for progesterone supplementation Progesterone for luteal support has been administered via the oral, intramuscular and vaginal routes. As described above, oral administration results in inadequate circulating concentrations, even when the steroid is provided in micronized form (Levine and Watson, 2000). This has been reflected in several randomized trials, in which oral progesterone was associated with significantly lower implantation and pregnancy rates, higher miscarriage rates, or both, compared with intramuscular or vaginal administration (Friedler et al., 1999; Licciardi et al., 1999). Moreover, the principal metabolites of progesterone formed after oral administration are 5α-reduced compounds that produce a somnolent effect comparable with that of benzodiazepines (Arafat et al., 1988). As a result, attempts to increase the dose sufficiently to achieve adequate circulating concentrations result in an unacceptable incidence of adverse events; a randomized comparative trial showed that the incidence of adverse effects, particularly sedation, was greater after oral administration than after vaginal administration (Pouly et al., 1996). Hence, oral administration is inappropriate for luteal support. Intramuscular administration of progesterone in oil has been widely used in assisted reproductive technologies. This approach produces circulating concentrations that may be above the physiological range, and it is associated with normal endometrial development and pregnancy rates (Devroey et al., 1989; Bourgain et al., 1990; Smitz et al., 1992a). However, intramuscular injection is uncomfortable for the patient and

3 can produce potentially serious adverse effects, such as injury to the sciatic nerve, with impairment of sensory or motor function of the lower extremity (Kline et al., 1998), allergic reactions to the oil vehicle, or injection site reactions. Furthermore, a dosing standard has not been established for intramuscular progesterone. Vaginal administration of progesterone offers a number of advantages in terms of patient convenience and tolerability. Early studies showed that vaginal administration was at least as effective as intramuscular administration, and significantly more effective than oral treatment, in terms of endometrial histology and outcome after IVF (Devroey et al., 1989; Bourgain et al., 1990; Smitz et al., 1992a). Paradoxically, however, these clinical benefits were achieved in the face of low circulating progesterone concentrations (Miles et al., 1994). Indeed, normal synchronous endometrial development occurred only after vaginal administration, rather than intramuscular or oral administration, even though the serum concentrations achieved were comparable with those resulting from oral administration (Figure 2) (Devroey et al., 1989; Bourgain et al., 1990). Such findings have led to the concept of a first uterine pass effect, whereby progesterone reaches the uterus directly after vaginal administration, without first passing through the liver (Bulletti et al., 1997; Fanchin et al., 1997; Cicinelli et al., 2000). Support for such an effect comes from ex-vivo studies, which have shown that endometrial progesterone concentrations reach steady state within 5 h after vaginal administration (Bulletti et al., 1997); similar accumulation is seen in vivo after vaginal administration, but not after intramuscular injection (Cicinelli et al., 2000). Several mechanisms have been proposed to account for the first uterine pass effect, including passive diffusion, passage through the cervical lumen, transport via the venous or lymphatic circulation, and counter-current exchange between utero-vaginal veins and arteries (Cicinelli and de Ziegler, 1999). There is direct evidence for counter-current vagina-touterus transport from animal and clinical studies, which have shown elevated concentrations of progesterone in the uterine artery following vaginal application (Einer-Jensen et al., 1993; Cicinelli et al., 1998; Cicinelli and de Ziegler, 1999; Cicinelli et al., 2001). Further evidence of the counter-current transfer mechanism comes from a study using vaginally administered 99m Tc-pertechnetate. Six post-menopausal women preparing to undergo abdominal hysterectomy received 0.2 ml 99m Tc-pertechnetate vaginally. In three of the patients, the cervical canal was previously sealed with surgical glue. Radioactivity was monitored in the uterus and in sites where 99m Tc-pertechnetate normally accumulates (thyroid, salivary glands and stomach) every 30 min for 6 h. Activity was detected in the uterus after 60 min and peaked between 120 and 210 min. This was true for patients with an open cervical canal, as well as for those with cervical occlusion. Thyroid uptake was noted at 180 min, with peak concentrations between 210 and 330 min. By contrast, control patients who received intravenous administration of 99m Tc-pertechnetate did not exhibit any uterine uptake at all. In the controls, rapid thyroid uptake occurred within 30 min. The appearance of 99m Tc-pertechnetate in extrapelvic sites following vaginal administration suggests that ultimately the material did reach the circulatory system. However, the more rapid appearance of the radionuclide in the uterus following vaginal administration and the absence of radionuclide in the uterus following intravenous administration strongly suggests the existence of a preferential distribution from vagina to uterus (Cicinelli et al., 2001). The finding that vaginal administration of progesterone produces high concentrations of progesterone in uterine tissue, and is associated with synchronous endometrial transformation, suggests that this route represents a more physiological form of progesterone replacement than intramuscular injection. Local bioavailability in the uterus is greater after vaginal administration than with other routes (Tavaniotou et al., 2000), and this might be expected to result in an increased chance of implantation and pregnancy after IVF. A recent publication on luteal phase support reported the results of a consensus meeting. The analysis concludes that Figure 2. Serum progesterone concentrations and endometrial development after vaginal, intramuscular and oral administration of progesterone. Vaginal administration resulted in the best endometrial development, although the circulating concentrations achieved were low and comparable with those seen after oral administration. Reproduced with permission from Devroey et al. (1989). 289

4 Table 1. Pharmacokinetic parameters of progesterone after vaginal administration of progesterone gel, 90 mg, and oral administration of progesterone capsules, 100 mg (Levine and Watson, 2000). Results are presented as means ± SD. Progesterone gel, Progesterone capsules, 90 mg (n = 6) 100 mg (n = 6) C Max (ng/ml) ± ± 3.06 a Dose-normalized C Max (ng/ml/mg) 0.12 ± ± a C Avg(0 24) (ng/ml) 5.55 ± ± 0.22 a T Max (h) 7.67 ± ± 0.41 AUC 0 24 (ng.h/ml) ± ± 5.15 a Dose-normalized AUC 0 24 (ng.h/ml/mg) 1.48 ± ± C Max = maximum concentration; C Avg(0 24) = mean drug concentration over 24 h after administration; T Max = time to maximum concentration; AUC 0 24 = area under concentration time curve to 24 h after administration; a P < 0.05, Student s t-test. 290 pregnancy rates after vaginal and intramuscular progesterone support are comparable, despite higher serum levels of progesterone after intramuscular administration (Penzias, 2002). Clinical experience with vaginal micronized progesterone gel Crinone 8% (Serono International, Geneva, Switzerland) is a vaginal gel containing 90 mg micronized progesterone in an oil-in-water emulsion on a polycarbophil base, delivered via a special applicator. The polycarbophil base ensures that the gel adheres to the vaginal epithelium, while the emulsion provides an oily depot from which progesterone is continuously released into the aqueous phase and hence into the tissue. The clinical experience with this formulation has shown that it provides a physiological progesterone-release profile, which is associated with favourable outcomes after IVF. By contrast to intramuscular progesterone, which is not associated with a recognized dosing standard, with vaginal micronized progesterone gel, a consistent quantity of progesterone can be delivered over 24 h. Pharmacokinetics The pharmacokinetics of vaginal progesterone delivered via vaginal progesterone gel have been compared with those of oral progesterone in a randomized study involving 12 healthy post-menopausal women (Levine and Watson, 2000). Serum progesterone was measured by radioimmunoassay or liquid chromatography mass spectrometry over 96 h after administration of progesterone gel (Crinone 8%), 90 mg, or progesterone capsules (Prometrium; Solvay Pharmaceuticals Inc., Marietta, GA, USA), 100 mg. Peak serum concentrations and systemic bioavailability of progesterone were significantly higher after vaginal administration of progesterone gel than after oral administration (Table 1). Furthermore, the time to peak concentrations was longer with progesterone gel than with oral administration (Table 1), indicating that vaginal administration achieves higher and more sustained progesterone concentrations than oral administration. Moreover, the inter-individual variability in peak concentrations was about 40-fold lower with vaginal progesterone gel than with oral progesterone. Comparison of the serum concentrations measured by the two techniques showed that radioimmunoassay consistently overestimated serum progesterone concentrations after oral administration but not after vaginal administration (Figure 1). This was attributable to the formation of cross-reacting metabolites after oral administration, due to first pass metabolism in the gut and liver. Endometrial histology The beneficial effects on the endometrium of vaginal administration of progesterone via Crinone gel were demonstrated in a randomized study involving 40 women without functioning ovaries (Fanchin et al., 1997). Oestrogen priming was given for 28 days, and progesterone given at doses of 45 mg (Crinone 4%), 90 mg (Crinone 8%) or 180 mg (2 90 mg) on alternate days from day 15 to day 27. Endometrial biopsies were taken on days 20 and 24 for endometrial dating and measurement of tissue oestrogen and progesterone receptors. All patients showed secretory transformation in the glands on day 20 and in the stroma on day 24. The distribution of oestrogen and progesterone receptors was comparable with that seen during normal menstrual cycles. Mean plasma progesterone concentrations were 2.4 ± 0.4 ng/ml in the group receiving 45 mg, 3.6 ± 0.2 ng/ml in those receiving 90 mg (Crinone 8%), and 3.4 ± 0.4 ng/ml in those receiving 180 mg. Thus, this study showed that vaginal administration of progesterone via Crinone gel results in normal endometrial transformation. Efficacy in donor egg cycles The efficacy of luteal support with progesterone gel has been investigated in donor egg cycles in women without inherent ovarian function (Gibbons et al., 1998; Jobanputra et al., 1999), since this situation represents a more rigorous test of efficacy than use in IVF cycles (in which luteal support is used to supplement endogenous progesterone production). In an initial study, 72 women with premature ovarian failure or diminished ovarian reserve were randomized to receive intramuscular progesterone, 100 mg, on days (n = 18) or progesterone gel, 90 mg twice daily, from day 14 (n = 54)

5 (Gibbons et al., 1998). Both groups also received oestradiol via transdermal patches. Patients underwent a mock cycle, during which endometrial biopsy was performed on day 26, followed by a second cycle, in which embryo transfer was performed. Implantation and ongoing (>20 weeks) pregnancy rates in patients receiving progesterone gel were 23% and 31%, respectively, compared with 18% and 22%, respectively, in patients receiving intramuscular progesterone. The endometrial biopsies performed in the mock cycle were read as in phase in all patients regardless of treatment regimen. However, those patients in the arm of the study that received intramuscular progesterone had higher serum progesterone levels than those in the vaginal administration arm. In an extension of this study, using the same design (Jobanputra et al., 1999), 86 patients were treated with progesterone gel, 90 mg once daily (n = 42), or intramuscular progesterone, 100 mg/day (n = 44). Histological examination on day 26 showed that the endometrium was in phase in all women treated with vaginal progesterone gel and in 42 women (95.5%) receiving intramuscular progesterone; there was no correlation between endometrial development and serum progesterone concentrations. Implantation and ongoing pregnancy rates were 22% and 39%, respectively, in women treated with vaginal progesterone gel, compared with 19% and 35% in women treated with intramuscular progesterone. The combined data from this series of studies (Table 2), therefore, shows that luteal support with progesterone gel is at least as effective as intramuscular progesterone in women with no endogenous ovarian function. Efficacy in IVF cycles A number of recent studies have investigated the efficacy of progesterone gel in patients undergoing IVF. In one study (Chantilis et al., 1999), 100 patients who received progesterone gel, 90 mg/day beginning on the evening of oocyte retrieval, were compared with a historical group (n = 106) who had received intramuscular progesterone, 50 mg/day. In both groups, most patients underwent a standard GnRH analogue down-regulation protocol; patients considered to be poor responders underwent a microflare protocol, consisting of a low dose of GnRH analogue in combination with an oral contraceptive. The results of this study are summarized in Table 3. Women who received progesterone gel tended to show higher rates of biochemical pregnancy loss but a lower incidence of clinical pregnancy loss (i.e. spontaneous abortion). In this study, clinical pregnancy was defined as the presence of a gestational sac, irrespective of the presence of fetal heartbeats on ultrasonic examination. Hence, the differences in biochemical and clinical pregnancy losses between the groups, particularly in women aged years, could be attributed to a higher number of gestational sacs without fetal heartbeats in the progesterone gel group (Chantilis et al., 1999). A second report has described the experience with progesterone gel in an open series of 43 patients enrolled in an IVF programme with historical pregnancy rates of more than 50% (Schoolcraft et al., 2000). These patients were compared with a concurrent control group who received intramuscular progesterone, 50 mg/day, and with historical data reported to the Society for Assisted Reproduction Therapy (SART) (Centres for Disease Control and Prevention, 1998). Patients receiving progesterone gel had undergone more previous IVF attempts (1.6 ± 0.9 versus 0.7 ± 0.8, P < 0.001), and the stimulation period was significantly longer (9.7 ± 1.2 days versus 9.1 ± 1.2 days, P < 0.05) compared with those receiving intramuscular progesterone. Nevertheless, comparable clinical pregnancy and live birth rates were achieved with the two regimens, and these data were comparable with those previously reported to SART (Table 4). This study also showed significant patient preferences for vaginal progesterone gel over intramuscular injection. Among patients who had previously received intramuscular progesterone, 76.9% preferred vaginal progesterone gel to intramuscular injection; 69.2% considered that the gel was easier to use; 76.9% considered it less painful; and 61.5% felt that it was less time-consuming. A recent report has reviewed the clinical experience with progesterone gel in 1184 women from 16 centres in the USA (Levine, 2000). The clinical pregnancy rate in women receiving progesterone gel was 35.1%, compared with 33.6% in SART historical controls, who had not used progesterone gel. There have been several retrospective analyses (Coutifaris et al., 2000; Williams et al., 2000). In one retrospective analysis of IVF outcomes in 118 consecutive good prognosis patients (age <40 years, more than seven embryos on day 1, with cryopreserved embryos remaining after embryo transfer), implantation and clinical pregnancy rates were 33% and 47%, respectively, with vaginal progesterone gel, and 43% and 53%, respectively, with intramuscular progesterone (Coutifaris et Table 2. Clinical outcomes in donor egg cycles with vaginal progesterone gel or intramuscular progesterone (Gibbons et al., 1998; Jobanputra et al., 1999). There was no significant difference in any outcome measure between once or twice daily vaginal progesterone gel and intramuscular progesterone. Vaginal progesterone gel, Vaginal progesterone gel, Intramuscular progesterone, 90 mg once daily 90 mg twice daily 100 mg/day (combined data in bold type) No. of cycles Implantation rate (%) Clinical pregnancy rate (%) Miscarriage rate (%) Ongoing pregnancy rate (%) Implantation rate = number of gestational sacs/number of embryos transferred; clinical pregnancy rate = number of women with gestational sacs/number of women undergoing embryo transfer; miscarriage rate = number of women with miscarriage/number of women with clinical pregnancies; ongoing pregnancy rate = number of women with pregnancies beyond 20 weeks/number of women undergoing embryo transfer. 291

6 Table 3. Clinical outcome of IVF in 206 women receiving luteal support with vaginal progesterone gel, 90 mg/day, or intramuscular progesterone, 50 mg/day (Chantilis et al., 1999). <35 years years >39 years Vaginal Progesterone Vaginal Progesterone Vaginal Progesterone progesterone i.m. progesterone i.m. progesterone i.m. gel gel gel Biochemical pregnancy 25/47 (53.2) 31/63 (49.2) 22/45 (48.9) 16/36 (44.4) 1/8 (12.5) 2/7 (28.6) (β-hcg >5 miu/ml) rate (%) Biochemical pregnancy 6/25 (24.0) 3/31 (9.7) 7/22 (31.8) 0/16 (0) a 0/8 (0) 1/2 (50) loss (%) Clinical pregnancy rate (%) 19/47 (40.4) 28/63 (44.4) 15/45 (33.3) 16/36 (44.4) 1/8 (12.5) 1/7 (14.3) Spontaneous abortion (%) 2/19 (10.5) 5/28 (17.9) 0/15 (0) 3/16 (18.8) 1/1 (100) 0/1 (0) Ongoing (>12 weeks) pregnancy rate (%) 17/47 (36.2) 23/63 (36.5) 15/45 (33.3) 13/36 (36.1) 0/8 (0) 1/7 (14.3) a P < 0.05 versus vaginal progesterone gel. Table 4. Clinical outcome of IVF in women receiving luteal support with vaginal progesterone gel, 90 mg/day, or intramuscular progesterone, 50 mg/day, compared with historical data reported to the Society for Assisted Reproduction Therapy (SART) (Schoolcraft et al., 2000). Vaginal progesterone gel Concurrent controls Intramuscular progesterone Data from SART (Chantilis et al., 1999) a <35 years years >39 years No. transfers No. biochemical pregnancies (%) 31 (72.1) 34 (73.9) No. clinical pregnancies (%) 26 (60.5) 28 (60.9) 104 (63.4) 94 (63.9) 32.3 (30) No. live births (%) 23 (53.5) 23 (50.0) 95 (57.7) 76 (51.7) 23.7 (22) a Last data set that did not include women receiving vaginal progesterone gel. 292 al., 2000). By contrast, a very recent retrospective study (Williams et al., 2000) found that in patients undergoing frozen embryo transfer, the clinical pregnancy rate in patients treated with vaginal progesterone gel was 39%, compared with 30% in women receiving vaginal progesterone tablets, 200 mg t.i.d., and 23% in women receiving intramuscular progesterone, 50 mg/day. Prospective, randomized studies comparing vaginal progesterone gel and intramuscular progesterone in women undergoing IVF/embryo transfer are few in number. One prospective study (Saucedo et al., 2000) found no significant difference in pregnancy rates between patients treated with vaginal progesterone gel and those receiving intramuscular progesterone, while both treatments were more effective than oral progesterone. Another open-label trial randomized 201 women using several different stimulation protocols to either vaginal progesterone gel or intramuscular progesterone. A luteal phase GnRH agonist suppression protocol was used in 81% of the patients assigned to vaginal progesterone gel and in 74% of the patients randomized to intramuscular progesterone. Among 83 women under the age of 35 years, 44 took intramuscular progesterone and 39 received Crinone. There was no difference in positive serum pregnancy rate between these groups, although there was a difference in clinical pregnancy rate, implantation rate and delivery rate. By contrast, for the 118 women aged 35 and above, there was no difference in implantation rate, clinical pregnancy rate or delivery rate between those using Crinone and intramuscular progesterone (Probst et al., 2001). The two randomized trials cited above yielded somewhat different results. In the first, no differences were observed between groups, whereas the second study found differences in a subgroup of women below the age of 35. While randomization does reduce the possibility of confounding variables, it does not always ensure the balance of all confounding factors, especially when the sample size is small (Barnhart and Sammel, 2002). A recent comparative cohort study evaluated progesterone levels, pregnancy rates and tolerability of a vaginal progesterone pessary and micronized progesterone capsules. The authors reported similar treatment efficacy but better tolerance of the pessary (Germond et al., 2002). Several studies have compared the efficacy of vaginal progesterone gel and other vaginal progesterone preparations. These studies have shown that the implantation or pregnancy

7 predominantly in non-pregnant women. Therefore, one can conclude that bleeding reflects the lack of a viable pregnancy rather than inadequacy of luteal support. Figure 3. Serum oestradiol concentrations in women undergoing IVF-intracytoplasmic sperm injection (ICSI) who were treated with vaginal micronized progesterone, 200 mg t.i.d. (Romàn et al., 2000). Concentrations in women who bled before discontinuation of progesterone treatment (B) were significantly lower than in women who did not menstruate (P < , Student s t-test). The lower bar, lower edge of box, middle line, upper edge of box, and upper bar correspond to the 10th, 25th, 50th, 75th and 90th quartiles, respectively; outliers are shown as square dots. rates achieved in women using progesterone gel as Crinone 8% are at least comparable to (Alper and Penzias, 2000; Ludwig and Diedrich, 2001) or superior to (Schwartz et al., 2000) those in women in whom progesterone was delivered via vaginal suppositories. Bleeding patterns during vaginal progesterone treatment Experience in patients treated with intramuscular progesterone has shown that menstrual bleeding is prevented for the duration of progesterone treatment, but relatively little information is available concerning bleeding patterns in women receiving vaginal progesterone. This issue was studied in a trial involving 149 women undergoing IVF and intracytoplasmic sperm injection (ICSI) using a long agonist protocol (Romàn et al., 2000). Micronized vaginal progesterone, 200 mg t.i.d., was given for a minimum of days after HCG administration, beginning on the day before oocyte retrieval. In the absence of pregnancy, the mean time to menses was 19.2 days, indicating that vaginal progesterone treatment was not associated with the shortening of the luteal phase. Bleeding occurred in 65% of non-pregnant women before the discontinuation of progesterone treatment; this was associated with a significant reduction in circulating oestradiol concentrations, compared with women who did not menstruate (Figure 3). Progesterone administration, regardless of its mode of administration, would not be expected to change circulating oestradiol concentration. Of the 52 women who became pregnant, only three bled before discontinuation of progesterone: of these, two had biochemical pregnancies, which disappeared spontaneously, and one proceeded to a full-term pregnancy. Thus, early bleeding in women receiving vaginal progesterone occurred An important new study on early pregnancy loss in IVF gives hope to those who do experience either a chemical pregnancy or a clinical miscarriage. A retrospective analysis of 4849 IVF cycles between January 1996 and October 2000 at Brigham and Women s Hospital in Boston shows a pregnancy loss rate, including both biochemical and clinical spontaneous abortions, of 26.3% during the study period. However, those patients who experienced a pregnancy loss had a 59% higher chance of achieving an ongoing pregnancy in the next cycle compared with women who had not demonstrated implantation initially (37.7% versus 27.3%; P = ; odds ratio [OR] 1.59; 95% CI, ). The authors speculate that pregnancy losses are often the result of chromosomally abnormal embryos and do not reflect the efficacy of IVF. Furthermore, they hypothesize that undiagnosed uterine factor infertility may account for a subset of IVF patients who have repeated IVF failures despite adequate response to stimulation and acceptable embryo quality (Bates and Ginsburg, 2002). Conclusions Luteal support with exogenous progesterone has an established role after IVF. The majority of the published literature indicates that vaginal and intramuscular routes of progesterone administration appear equivalent. The clinical experience reported here with vaginal progesterone gel (Crinone 8%) shows that this preparation provides effective and convenient luteal support in patients undergoing IVF. Acknowledgements Thanks to Joan Schertz for assistance with the preparation of this manuscript. Financial support was provided by Serono International, Geneva, Switzerland. References Abate A, Brigandi A, Abate FG et al Luteal phase support with 17alpha-hydroxyprogesterone versus unsupported cycles in in vitro fertilization: a comparative randomized study. Gynecologic and Obstetric Investigation 48, Abramowicz JS, Archer DF 1990 Uterine endometrial peristalsis a transvaginal ultrasound study. Fertility and Sterility 54, Alper MM, Penzias AS 2000 Crinone offers excellent implantation rates in patients undergoing in vitro fertilization (IVF). 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