- Email: [email protected]
intrauterine insemination in unexplained sterility
Antral follicle count as a predictor of hyperresponse in controlled ovarian hyperstimulation/intrauterine insemination in unexplained sterility In this prospective study of women with unexplained infertility undergoing the first cycle of controlled ovarian hyperstimulation/intrauterine insemination, the presence of 16 or more antral follicles on day 3 of the cycle was a good predictor of cancellation due to hyperresponse. (Fertil Steril 2010;94:1105–7. 2010 by American Society for Reproductive Medicine.) Key Words: Intrauterine insemination, hyperresponse, high-order multiple pregnancies, antral follicle count, ovarian volume
Unexplained infertility is a diagnosis made by exclusion in couples who have not conceived and in whom standard-protocol investigations have not detected any abnormality. It accounts for 8%–37% of couples with infertility (1, 2). The use of controlled ovarian hyperstimulation (COH) with intrauterine insemination (IUI) asan alternative to in vitro fertilization (IVF) in couples with unexplained infertility was described for the first time in 1984 (3). The use of COH during the past three decades has significantly increased the rates of multiple pregnancy and ovarian hyperstimulation syndrome (OHSS). Multiple pregnancies reached epidemic proportions in the late 1990s, and the consequences for the children, the parents, and the community remain substantial (4). Whereas ovulation induction accounts for approximately 40% of the problem of high-order multiple pregnancies (HOMP), it accounts for almost 100% of the problem of very-HOMP. In both medical and social terms, such pregnancies can have highly negative effects. According to some studies, it appears that an individual infertile couple is at significantly greater risk of HOMP from ovulation induction alone or associated with IUI compared with IVF (5, 6). The incidence of severe OHSS in cycles in which ovarian stimulation is performed using gonadotropins has been reported to vary between 0.5% and 2.0% (7, 8). One strategy to avoid HOMP and OHSS is the cancellation of the cycle in the presence of three or more follicles of >16 mm in diameter and/or five or more total follicles of >11 mm. Up Miguel A. Checa, M.D. Maria Prat, M.D. Ramon Carreras, M.D. Department of Obstetrics and Gynecology, Hospital Universitari del Mar, Autonomous University of Barcelona, Barcelona, Spain Received July 24, 2009; revised September 24, 2009; accepted October 28, 2009; published online January 4, 2010. M.A.C. has nothing to disclose. M.P. has nothing to disclose. R.C. has nothing to disclose. Reprint requests: Miguel A. Checa, M.D., Department of Obstetrics and Gynecology, Hospital Universitari del Mar, Passeig Marıtim 25–29, E-08003 Barcelona, Spain (FAX: þ34-93-2483254; E-mail: [email protected]).
0015-0282/$36.00 doi:10.1016/j.fertnstert.2009.10.063
to 83% of reproductive endocrinologists in the United States uses cycle cancellation to prevent HOMP in COH-IUI (9). Cancellation due to hyperresponse occurs in 15% of COH-IUI cycles (10). A number of ovarian reserve markers have been examined to predict ovarian responses to gonadotropins during IVF–embryo transfer treatment (IVF-ET). Early follicular FSH concentration before the treatment cycle is a well known predictor of ovarian response, which has been shown to be better than the woman’s age (11). Recently, ultrasound assessment of the antral follicle count (AFC) has been considered to be the best clinical predictor of ovarian responses or successful outcome (12). The aim of the present study was to evaluate which parameters of ovarian reserve could be better predictors for cancellation of a cycle in COH/IUI due hyperresponse in women with unexplained infertility. Between January 2006 and December 2008, infertile women undergoing the first cycle of COH-IUI at the Unit of Reproductive Medicine of an acute care university-affiliated hospital in Barcelona, Spain, were included in this study. Inclusion criteria were: >1 year of infertility, regular menstrual cycles of 25–35 days, bilateral tubal patency confirmed by hysterosalpingography or laparoscopy, serum FSH concentration <10 IU/L measured in the third day of cycle, and R10 million total number of motile spermatozoa in the ejaculate during work-up studies. Exclusion criteria were: current smoking, R1 COH cycles, history of ovarian surgery, presence of another known cause of infertility, and diagnostic criteria (European Society for Human Reproduction and Embryology) of polycystic ovarian syndrome (13). The study required no modification of our routine COH-IUI protocols. Each patient was thoroughly counseled and gave informed consent before participating in the study. The study protocol was approved by the Institutional Review Board. All patients received recombinant FSH treatment (75 IU once daily by SC injection; Gonal F; Serono Espa~ na, Madrid, Spain) starting on day 3 of the menstrual cycle. From day 10 onward, the dose of recombinant FSH could be adjusted and individualized based on follicular growth detected on ultrasonography. Monitoring consisted of a baseline pelvic ultrasound on cycle day 3 to exclude ovarian cysts and to measure each antral follicle (sonolucent cystic area of R2 mm), which were counted through several frames to
Fertility and Sterility Vol. 94, No. 3, August 2010 Copyright ª2010 American Society for Reproductive Medicine, Published by Elsevier Inc.
1105
FIGURE 1 Prediction of hyperresponse according to (A) antral follicle count (AFC) and (B) ovarian volume. ROC ¼ receiver operating characteristic.
Checa. Correspondence. Fertil Steril 2010.
determine maximum diameter. The total numbers of follicles in both right and left ovaries were summed to count the total number of antral follicles (2–8 mm) for each patient. Ovarian volume was also evaluated. A blood sample was taken from each patient for baseline analysis of FSH levels, E2 level, total T concentration, and SHBGbound T. The follicles were routinely checked every 2 days from day 5 of stimulation until the day of recombinant hCG (Ovitrelle; Serono Espa~ na) injection. The hCG (250 mg) was given when at least one leading follicles reached a diameter of 18 mm. The number of dominant follicles (>14 mm) and E2 level were also determined on the day of hCG injection. The IUI was performed within 36 hours of recombinant hCG administration. To further prevent multiple gestations and OHSS, the cycle was canceled if three or more follicles >16 mm and/or five or more total follicles >11 mm were detected (hyperresponse). All control tests were performed by a senior gynecologist (M.P.), and to decide cancellation a consultation with the head of the reproductive unit (M.A.) was done in all cases. A pregnancy test was performed 15 days after hCG administration if the expected menses was delayed. According to a risk of cancellation due to hyperresponse of 15%, with an alpha level of 0.05 and a beta risk of 0.20 in a bilateral contrast, 13 cases of hyperresponse were needed in the first group and 104 patients not being canceled for a difference greater than five antral follicles detected at baseline monitoring. Categoric variables were compared with the chi-squared test or Fisher exact test and continuous variables with the Student t test for independent data. The area under the receiver operating characteristic curve was used to estimate the best cut-off points for the discriminating capacity of the AFC and ovarian volume. The sensitivity, specificity, and positive and negative predictive values of these cut-off values were calculated. Out of a total of 122 eligible women recruited during the study period, two were excluded (one became pregnant spontaneously and one moved to another place of residence). The study population included 120 women, 104 in the insemination group and 16 in the hyperresponse and cancellation group. There were no baseline differences between the groups of insemination and hyperresponse/cancellation regarding age, serum levels of FSH, E2, total T
1106
Checa et al.
Correspondence
and SHBG-bound T, and body mass index (BMI). Only the mean total number of antral follicles (9.9 4.45 vs. 19.7 2.9) and ovarian volume (10.9 4.2 mL vs. 15.6 2 .3 mL) were higher in the group of patients with hyperresponse (P<.001). For the cut-off of 16 or more antral follicles, there was a 100% sensitivity (95% confidence interval [CI] 79.4–100), 93.3% specificity (95% CI 86.6–97.2), 69.6% positive predictive value (95% CI 47.1– 86.8), and 100% negative predictive value (95% 96.3–100). For the cut-off value of 13.35 mL total ovarian volume, the sensitivity was 87.6% (95% CI 61.7–98.4), the specificity 79.8% (95% CI 70.8–87), the positive predictive value 40% (95% CI 23.9–57.9), and the negative predictive value 97.6% (95% CI 91.8–99.7) (Fig. 1). The presence of R16 antral follicles on day 3 of the cycle is a good predictor of hyperresponse in COH in women with unexplained infertility undergoing a standard step-up protocol started with 75 IU recombinant FSH. Cycle cancellation is a common strategy to prevent HOMP and OHSS (9). In the present series, the rate of cycle cancellation of 13.3% was similar to that reported in other studies (10). The AFC is a useful parameter to assess ovarian reserve in IVF, and many authors have explored this measure as a predictor of response or prognosis of pregnancy (14). However, this test is not routinely used in cycles of COH for IUI, although it is easy to perform at the beginning of the cycle and is able to detect patients at high-risk of cancellation. The small sample of patients is a limitation of the study, although the number of cycles canceled is sufficient to support statistically the prognostic value of the AFC. In fact, the sensitivity of 100% and specificity of 93.3% of the AFC indicate the clinical relevance of this variable. Age was not a significant predictive variable of hyperresponse in this study, although age has been demonstrated to be an important prognostic factor for successful outcome in assisted reproduction. Basal FSH on the third day of the cycle of <10 IU/L has been the most frequently used marker of ovarian reserve, with a sensitivity of 87% and a specificity of 100% for a good response (15). In the present study, baseline serum FSH or E2 levels were not useful predictors of high-risk cycle cancellation in women
Vol. 94, No. 3, August 2010
undergoing standard COH-IUI protocol. Patients with AFC >16 may benefit with the use of protocols with lower doses, such as 37.5 50 IU recombinant FSH (16).
In conclusion, the AFC on the third day of the cycle allows us to discriminate which patients have to modify the standard stimulation protocols.
REFERENCES 1. ESHRE Capri Workshop Group. Diagnosis and management of the infertile couple: missing information. Hum Reprod Update 2004;10: 295–307. 2. Collins JA, Corsignani PG. Unexplained infertility: a review of diagnosis, prognosis, treatment efficacy and management. Int J Gynecol Obstet 1992;39: 267–75. 3. Sher G, Knutzen VK, Stratton CJ, Montakhab MM, Allenson SG. In vitro sperm capacitation and transcervical intrauterine insemination for the treatment of refractory infertility: phase I. Fertil Steril 1984;41:260–4. 4. Jones HW. Multiple births: how are we doing? Fertil Steril 2003;79:7–21. 5. Guzick DS, Carson SA, Coutifaris C, Overstreet JW. Efficacy of superovulation in intrauterine insemination in the treatment of infertility. N Engl J Med 1999;340:177–83. 6. Tur R, Barri PN, Coroleu B, Buxaderas R, Parera N, Balasch J. Use of a prediction model for high-order multiple implantation after ovarian stimulation with gonadotropins. Fertil Steril 2005;83:116–21.
Fertility and Sterility
7. Rizk B. Ovarian hyperstimulation syndrome— epidemiology, pathophysiology, prevention and management. New York: Cambridge University Press, 2006: 10–33. 8. Soares SR, Gomez R, Simon C, Garcıa-Velasco JA, Pellicer A. Targeting the vascular endothelial growth factor system to prevent ovarian hyperstimulation syndrome. Hum Reprod Update 2008;14:321–33. 9. Hock DL, Seifer DB, Kontopoulos E, Ananth CV. Practice patterns among board-certified reproductive endocrinologists regarding highorder multiple gestations: a United States national survey. Obstet Gynecol 2002;99:763–70. 10. Dickey RP, Taylor SN, Lu PY, Sartor BM, Rye PH, Pyrzak R. Risk factors for higher order multiple pregnancy and multiple birth after controlled ovarian hyperstimulation; results of 4,062 IUI cycles. Fertil Steril 2005;83:671–83. 11. Sharif K, Elgendy M, Lashen H, Afnan M. Age and basal follicle stimulating hormone as predictors of in vitro fertilisation outcome. Br J Obstet Gynecol 1998;105:107–12. 12. Hendriks DJ, Mol BW, Bancsi LF, Te Velde ER, Broekmans FJ. Antral follicle count in the
13.
14.
15.
16.
prediction of poor ovarian response and pregnancy after in vitro fertilization: a meta-analysis and comparison with basal follicle-stimulating hormone level. Fertil Steril 2005;83:291–301. Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop group. Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome (PCOS). Hum Reprod 2004;19:41–7. Boekmans FJ Slaats P, Hendriks DJ, Mol BW. A systemic review of test predicting ovarian reserve and IVF outcome. Hum Reprod Update 2006;12: 685–718. Ramalho de Carvalho B Japur C, Rosa JC, Dos Reis RM, Ferriani RA, Silva de Sa MF. Ovarian reserve evaluation: state of the art. J Assist Reprod Genet 2008;25:311–22. Calaf Alsina J, Ruiz Balda JA, Romeu Sarrio A, Caballero Fernandez V, Cano Trigo I, Gomez Parga JL, et al. Ovulation induction with a starting dose of 50 IU of recombinant follicle stimulating hormone in WHO group II anovulatory women: the IO-50 study, a prospective, observational, multicentre, open trial. BJOG 2003;110:1072–7.
1107
Unexplained infertility is a diagnosis made by exclusion in couples who have not conceived and in whom standard-protocol investigations have not detected any abnormality. It accounts for 8%–37% of couples with infertility (1, 2). The use of controlled ovarian hyperstimulation (COH) with intrauterine insemination (IUI) asan alternative to in vitro fertilization (IVF) in couples with unexplained infertility was described for the first time in 1984 (3). The use of COH during the past three decades has significantly increased the rates of multiple pregnancy and ovarian hyperstimulation syndrome (OHSS). Multiple pregnancies reached epidemic proportions in the late 1990s, and the consequences for the children, the parents, and the community remain substantial (4). Whereas ovulation induction accounts for approximately 40% of the problem of high-order multiple pregnancies (HOMP), it accounts for almost 100% of the problem of very-HOMP. In both medical and social terms, such pregnancies can have highly negative effects. According to some studies, it appears that an individual infertile couple is at significantly greater risk of HOMP from ovulation induction alone or associated with IUI compared with IVF (5, 6). The incidence of severe OHSS in cycles in which ovarian stimulation is performed using gonadotropins has been reported to vary between 0.5% and 2.0% (7, 8). One strategy to avoid HOMP and OHSS is the cancellation of the cycle in the presence of three or more follicles of >16 mm in diameter and/or five or more total follicles of >11 mm. Up Miguel A. Checa, M.D. Maria Prat, M.D. Ramon Carreras, M.D. Department of Obstetrics and Gynecology, Hospital Universitari del Mar, Autonomous University of Barcelona, Barcelona, Spain Received July 24, 2009; revised September 24, 2009; accepted October 28, 2009; published online January 4, 2010. M.A.C. has nothing to disclose. M.P. has nothing to disclose. R.C. has nothing to disclose. Reprint requests: Miguel A. Checa, M.D., Department of Obstetrics and Gynecology, Hospital Universitari del Mar, Passeig Marıtim 25–29, E-08003 Barcelona, Spain (FAX: þ34-93-2483254; E-mail: [email protected]).
0015-0282/$36.00 doi:10.1016/j.fertnstert.2009.10.063
to 83% of reproductive endocrinologists in the United States uses cycle cancellation to prevent HOMP in COH-IUI (9). Cancellation due to hyperresponse occurs in 15% of COH-IUI cycles (10). A number of ovarian reserve markers have been examined to predict ovarian responses to gonadotropins during IVF–embryo transfer treatment (IVF-ET). Early follicular FSH concentration before the treatment cycle is a well known predictor of ovarian response, which has been shown to be better than the woman’s age (11). Recently, ultrasound assessment of the antral follicle count (AFC) has been considered to be the best clinical predictor of ovarian responses or successful outcome (12). The aim of the present study was to evaluate which parameters of ovarian reserve could be better predictors for cancellation of a cycle in COH/IUI due hyperresponse in women with unexplained infertility. Between January 2006 and December 2008, infertile women undergoing the first cycle of COH-IUI at the Unit of Reproductive Medicine of an acute care university-affiliated hospital in Barcelona, Spain, were included in this study. Inclusion criteria were: >1 year of infertility, regular menstrual cycles of 25–35 days, bilateral tubal patency confirmed by hysterosalpingography or laparoscopy, serum FSH concentration <10 IU/L measured in the third day of cycle, and R10 million total number of motile spermatozoa in the ejaculate during work-up studies. Exclusion criteria were: current smoking, R1 COH cycles, history of ovarian surgery, presence of another known cause of infertility, and diagnostic criteria (European Society for Human Reproduction and Embryology) of polycystic ovarian syndrome (13). The study required no modification of our routine COH-IUI protocols. Each patient was thoroughly counseled and gave informed consent before participating in the study. The study protocol was approved by the Institutional Review Board. All patients received recombinant FSH treatment (75 IU once daily by SC injection; Gonal F; Serono Espa~ na, Madrid, Spain) starting on day 3 of the menstrual cycle. From day 10 onward, the dose of recombinant FSH could be adjusted and individualized based on follicular growth detected on ultrasonography. Monitoring consisted of a baseline pelvic ultrasound on cycle day 3 to exclude ovarian cysts and to measure each antral follicle (sonolucent cystic area of R2 mm), which were counted through several frames to
Fertility and Sterility Vol. 94, No. 3, August 2010 Copyright ª2010 American Society for Reproductive Medicine, Published by Elsevier Inc.
1105
FIGURE 1 Prediction of hyperresponse according to (A) antral follicle count (AFC) and (B) ovarian volume. ROC ¼ receiver operating characteristic.
Checa. Correspondence. Fertil Steril 2010.
determine maximum diameter. The total numbers of follicles in both right and left ovaries were summed to count the total number of antral follicles (2–8 mm) for each patient. Ovarian volume was also evaluated. A blood sample was taken from each patient for baseline analysis of FSH levels, E2 level, total T concentration, and SHBGbound T. The follicles were routinely checked every 2 days from day 5 of stimulation until the day of recombinant hCG (Ovitrelle; Serono Espa~ na) injection. The hCG (250 mg) was given when at least one leading follicles reached a diameter of 18 mm. The number of dominant follicles (>14 mm) and E2 level were also determined on the day of hCG injection. The IUI was performed within 36 hours of recombinant hCG administration. To further prevent multiple gestations and OHSS, the cycle was canceled if three or more follicles >16 mm and/or five or more total follicles >11 mm were detected (hyperresponse). All control tests were performed by a senior gynecologist (M.P.), and to decide cancellation a consultation with the head of the reproductive unit (M.A.) was done in all cases. A pregnancy test was performed 15 days after hCG administration if the expected menses was delayed. According to a risk of cancellation due to hyperresponse of 15%, with an alpha level of 0.05 and a beta risk of 0.20 in a bilateral contrast, 13 cases of hyperresponse were needed in the first group and 104 patients not being canceled for a difference greater than five antral follicles detected at baseline monitoring. Categoric variables were compared with the chi-squared test or Fisher exact test and continuous variables with the Student t test for independent data. The area under the receiver operating characteristic curve was used to estimate the best cut-off points for the discriminating capacity of the AFC and ovarian volume. The sensitivity, specificity, and positive and negative predictive values of these cut-off values were calculated. Out of a total of 122 eligible women recruited during the study period, two were excluded (one became pregnant spontaneously and one moved to another place of residence). The study population included 120 women, 104 in the insemination group and 16 in the hyperresponse and cancellation group. There were no baseline differences between the groups of insemination and hyperresponse/cancellation regarding age, serum levels of FSH, E2, total T
1106
Checa et al.
Correspondence
and SHBG-bound T, and body mass index (BMI). Only the mean total number of antral follicles (9.9 4.45 vs. 19.7 2.9) and ovarian volume (10.9 4.2 mL vs. 15.6 2 .3 mL) were higher in the group of patients with hyperresponse (P<.001). For the cut-off of 16 or more antral follicles, there was a 100% sensitivity (95% confidence interval [CI] 79.4–100), 93.3% specificity (95% CI 86.6–97.2), 69.6% positive predictive value (95% CI 47.1– 86.8), and 100% negative predictive value (95% 96.3–100). For the cut-off value of 13.35 mL total ovarian volume, the sensitivity was 87.6% (95% CI 61.7–98.4), the specificity 79.8% (95% CI 70.8–87), the positive predictive value 40% (95% CI 23.9–57.9), and the negative predictive value 97.6% (95% CI 91.8–99.7) (Fig. 1). The presence of R16 antral follicles on day 3 of the cycle is a good predictor of hyperresponse in COH in women with unexplained infertility undergoing a standard step-up protocol started with 75 IU recombinant FSH. Cycle cancellation is a common strategy to prevent HOMP and OHSS (9). In the present series, the rate of cycle cancellation of 13.3% was similar to that reported in other studies (10). The AFC is a useful parameter to assess ovarian reserve in IVF, and many authors have explored this measure as a predictor of response or prognosis of pregnancy (14). However, this test is not routinely used in cycles of COH for IUI, although it is easy to perform at the beginning of the cycle and is able to detect patients at high-risk of cancellation. The small sample of patients is a limitation of the study, although the number of cycles canceled is sufficient to support statistically the prognostic value of the AFC. In fact, the sensitivity of 100% and specificity of 93.3% of the AFC indicate the clinical relevance of this variable. Age was not a significant predictive variable of hyperresponse in this study, although age has been demonstrated to be an important prognostic factor for successful outcome in assisted reproduction. Basal FSH on the third day of the cycle of <10 IU/L has been the most frequently used marker of ovarian reserve, with a sensitivity of 87% and a specificity of 100% for a good response (15). In the present study, baseline serum FSH or E2 levels were not useful predictors of high-risk cycle cancellation in women
Vol. 94, No. 3, August 2010
undergoing standard COH-IUI protocol. Patients with AFC >16 may benefit with the use of protocols with lower doses, such as 37.5 50 IU recombinant FSH (16).
In conclusion, the AFC on the third day of the cycle allows us to discriminate which patients have to modify the standard stimulation protocols.
REFERENCES 1. ESHRE Capri Workshop Group. Diagnosis and management of the infertile couple: missing information. Hum Reprod Update 2004;10: 295–307. 2. Collins JA, Corsignani PG. Unexplained infertility: a review of diagnosis, prognosis, treatment efficacy and management. Int J Gynecol Obstet 1992;39: 267–75. 3. Sher G, Knutzen VK, Stratton CJ, Montakhab MM, Allenson SG. In vitro sperm capacitation and transcervical intrauterine insemination for the treatment of refractory infertility: phase I. Fertil Steril 1984;41:260–4. 4. Jones HW. Multiple births: how are we doing? Fertil Steril 2003;79:7–21. 5. Guzick DS, Carson SA, Coutifaris C, Overstreet JW. Efficacy of superovulation in intrauterine insemination in the treatment of infertility. N Engl J Med 1999;340:177–83. 6. Tur R, Barri PN, Coroleu B, Buxaderas R, Parera N, Balasch J. Use of a prediction model for high-order multiple implantation after ovarian stimulation with gonadotropins. Fertil Steril 2005;83:116–21.
Fertility and Sterility
7. Rizk B. Ovarian hyperstimulation syndrome— epidemiology, pathophysiology, prevention and management. New York: Cambridge University Press, 2006: 10–33. 8. Soares SR, Gomez R, Simon C, Garcıa-Velasco JA, Pellicer A. Targeting the vascular endothelial growth factor system to prevent ovarian hyperstimulation syndrome. Hum Reprod Update 2008;14:321–33. 9. Hock DL, Seifer DB, Kontopoulos E, Ananth CV. Practice patterns among board-certified reproductive endocrinologists regarding highorder multiple gestations: a United States national survey. Obstet Gynecol 2002;99:763–70. 10. Dickey RP, Taylor SN, Lu PY, Sartor BM, Rye PH, Pyrzak R. Risk factors for higher order multiple pregnancy and multiple birth after controlled ovarian hyperstimulation; results of 4,062 IUI cycles. Fertil Steril 2005;83:671–83. 11. Sharif K, Elgendy M, Lashen H, Afnan M. Age and basal follicle stimulating hormone as predictors of in vitro fertilisation outcome. Br J Obstet Gynecol 1998;105:107–12. 12. Hendriks DJ, Mol BW, Bancsi LF, Te Velde ER, Broekmans FJ. Antral follicle count in the
13.
14.
15.
16.
prediction of poor ovarian response and pregnancy after in vitro fertilization: a meta-analysis and comparison with basal follicle-stimulating hormone level. Fertil Steril 2005;83:291–301. Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop group. Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome (PCOS). Hum Reprod 2004;19:41–7. Boekmans FJ Slaats P, Hendriks DJ, Mol BW. A systemic review of test predicting ovarian reserve and IVF outcome. Hum Reprod Update 2006;12: 685–718. Ramalho de Carvalho B Japur C, Rosa JC, Dos Reis RM, Ferriani RA, Silva de Sa MF. Ovarian reserve evaluation: state of the art. J Assist Reprod Genet 2008;25:311–22. Calaf Alsina J, Ruiz Balda JA, Romeu Sarrio A, Caballero Fernandez V, Cano Trigo I, Gomez Parga JL, et al. Ovulation induction with a starting dose of 50 IU of recombinant follicle stimulating hormone in WHO group II anovulatory women: the IO-50 study, a prospective, observational, multicentre, open trial. BJOG 2003;110:1072–7.
1107