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Luteal phase progesterone increases live birth rate after frozen embryo transfer
Luteal phase progesterone increases live birth rate after frozen embryo transfer Kerstin Bjuresten, B.S.,a Britt-Marie Landgren, M.D., Ph.D.,a Outi Hovatta, M.D., Ph.D.,a and Anneli Stavreus-Evers, Ph.D.b a Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm; and b Department of Women’s and Children’s Health, Uppsala University, Uppsala, Sweden
Objective: To see if progesterone support has a beneficial effect on live birth rate after frozen embryo transfer in natural cycles. Design: Prospective randomized controlled trial. Setting: University-based hospital. Subject(s): Four hundred thirty-five women undergoing embryo transfer in natural cycles. Intervention(s): The women received either vaginal progesterone, 400 mg twice a day from the day of embryo transfer in natural cycles, or no progesterone support. Main Outcome Measure(s): Live birth rate, biochemical pregnancy rate, pregnancy rate, and spontaneous abortion rate. Result(s): Live birth rate were significantly greater in women receiving vaginal progesterone as luteal phase support after frozen–thawed embryo transfer in natural cycles compared with those who did not take progesterone. There were no differences in biochemical pregnancy rate, pregnancy rate, or spontaneous abortion rate. Conclusion(s): Progesterone supplementation improves live birth rate after embryo transfer in natural cycles. (Fertil Steril 2011;95:534–7. 2011 by American Society for Reproductive Medicine.) Key Words: Progesterone, pregnancy rate, live birth rate, frozen embryo transfer, natural menstrual cycle
Single-embryo transfer has become standard procedure to avoid multiple pregnancies in in vitro fertilization (IVF) and embryo transfer. Recently, it was shown that single-embryo transfer in combination with cryopreservation is more effective as regards cumulative birth rate, more cost-effective, and results in a lower number of twins than double-embryo transfer (1). Furthermore, the receptiveness of the endometrium is seriously compromised by controlled ovarian stimulation protocols (2). Therefore, transfer of frozen–thawed embryos in natural cycles is a preferred choice for women with normal ovulatory menstrual cycles. Progesterone is a prerequisite for development of the endometrium and implantation of an embryo. Transformation of the endometrium to a receptive phase depends on adequate progesterone exposure in addition to preceding estrogen priming (3). Low levels of circulating progesterone during early pregnancy may result in miscarriage (4). In women with proven fertility, production of progesterone from the corpus luteum is sufficient to support the endometrium and facilitate implantation. There is little controlled data regarding the need of progesterone supplementation if an embryo is transferred during a natural cycle to an infertile woman, and there is no consensus about the possible benefits of progesterone supplementation. There are varying practices among clinics; some offer supplementation with progesterone after embryo transfer in natural cycles, whereas others do not. Generally, there is a belief that endogenous
Received February 15, 2010; revised May 5, 2010; accepted May 6, 2010; published online June 26, 2010. K.B. has nothing to disclose. B.-M.L. has nothing to disclose. O.H. has nothing to disclose. A.S.-E. has nothing to disclose. Reprint requests: Anneli Stavreus-Evers, Ph.D., Department of Women’s and Children’s Health, Uppsala University Hospital, 751 85 Uppsala, Sweden (FAX: 46 8 18 55 97 75; E-mail: Anneli.Stavreus-Evers@kbh. uu.se).
534
production of progesterone is sufficient to support implantation in a natural cycle. Beneficial effects of high doses of progesterone after frozen embryo transfer in artificial cycles were shown by Orvieto et al. (5). In another report, after fresh embryo transfer there was no effect on pregnancy and implantation rates among women receiving micronized progesterone as luteal phase supplementation (6). Frozen–thawed embryo transfer in a natural cycle is a different situation. The women involved are often subfertile, and they may have suboptimal endometria during their natural cycles. In view of the above, we designed a prospective randomized study to investigate if pregnancy rates could be improved with vaginal progesterone supplementation during the luteal phase and early pregnancy after frozen–thawed embryo transfer.
MATERIALS AND METHODS Subjects Women scheduled for frozen embryo transfer were asked to participate in the study. Four hundred thirty-five women agreed to participate, and were randomized to either vaginal micronized progesterone supplementation (n ¼ 219) or to no supplementation (n ¼ 216). The women included had been initially diagnosed with unexplained infertility, tubal factor infertility, or male factor infertility.
Ethics The Ethics Committee at Karolinska Institutet approved the study. There is no institutional review board at Karolinska Institutet. None of the investigators had any conflict of interest in relation to this study. Informed oral and written consent was obtained from all participating women.
Study Design The study was designed as a prospective randomized controlled trial. At the day of embryo transfer, the women were asked to participate in the study. They were randomly allocated to either the progesterone or the no-progesterone group. Allocation was performed by using opaque sealed
Fertility and Sterility Vol. 95, No. 2, February 2011 Copyright ª2011 American Society for Reproductive Medicine, Published by Elsevier Inc.
0015-0282/$36.00 doi:10.1016/j.fertnstert.2010.05.019
FIGURE 1 The number of women included in the study, and the numbers of positive hCG test results, early miscarriages, clinical pregnancies, spontaneous abortions, and deliveries are shown.
477 invited Excluded n=42 435 included
216 No progsterone
60 positive hCG
54 clinical pregnancy
44 deliveries
156 not pregnant
6 early miscarriage
219 Progesterone
143 not pregnant
76 positive hCG
7 early miscarriage
10 spontaneous abortions
69 clinical pregnancy
4 spontaneous abortions
65 deliveries
Bjuresten. Progesterone and live birth rate. Fertil Steril 2011.
envelopes. The study was an open trial, because it was not possible to obtain a placebo alternative to micronized progesterone. The study was not supported by any pharmaceutical company, and the hospital pharmacy could not produce the placebo needed. Power calculation showed that 213 subjects in each group were needed to detect a difference of 15% at the 80% level and an a value of 0.05.
Treatment The control women did not receive any hormone supplementation. The treated women received vaginal micronized progesterone, 400 mg twice a day, starting from the evening of the day of embryo transfer. A vaginal ultrasonographic scan was performed once for each woman included in the study, on cycle days 10 to 14. The ovaries were visualized and the diameter of the leading follicle was measured. On the day the leading follicle had reached 16 mm in diameter, the women started daily urine tests in the morning to detect the LH surge, using Clearblue digital ovulation tests (Swiss Precision Diagnostics GmbH, Bedford, UK). Three days after the LH surge, the embryo/embryos were thawed and embryo transfer was performed. Embryo transfer was performed using either a Sidney K-jets-7019 SIVF catheter (COOK, Queensland, Australia) or an Emtrac 4219 Delphin catheter (Gynetics Medical products N.V., Hamont-Achel, Belgium). One midwife (K.B.) transferred all the embryos.
Outcome Measures The main outcome measures were positive pregnancy test results, indicated as measurable serum human chorionic gonadotropin (hCG) concentrations, early miscarriage rate, clinical pregnancy rate, spontaneous abortions, and live birth rate.
Statistics Statistical evaluation was performed by using a chi-square test, with SPSS software (SPSS, Chicago, IL, USA).
Fertility and Sterility
Definitions The quality of embryos transferred was evaluated as either grade A, with all blastomeres intact, or grade B, with between 50% and 100% of blastomeres intact. Lower quality embryos were not transferred. Pregnancy was confirmed by a positive result in a urine hCG test conducted 18 days after frozen embryo transfer. The positive hCG rate was determined as the ratio between the number of positive hCG tests and the total number of transfers. The clinical pregnancy rate was defined as the number of cases with evidence of at least one gestational sac, divided by the number of transfers. The early miscarriage rate was defined as the number of early pregnancy losses divided by the total number of transfers. The clinical abortion rate was defined as the number of clinical pregnancy losses before the 20th week of gestation divided by the number of transfers. The live birth rate was the ratio of live births to embryo transfers.
RESULTS Study Subjects Of the initial 477 women invited to participate, 435 were included in the study. Forty-two women were excluded for the following reasons: 34 did not want to participate, 3 presented with ovarian dysfunction, 2 received a donated oocyte, 1 had cancer, 1 had rheumatoid arthritis, and 1 was excluded because she was already included in another study (Fig. 1). Women who were later found to have endometriosis were included in the data analysis. The distribution of diagnoses was similar in the two groups (Table 1). The women who did not want to participate in the study had negative experiences of previous use of progesterone. The mean age of the women in the progesterone group was 35.0 3.68 years, and the mean age of the women in the no-progesterone group was 34.2 3.56 years.
535
TABLE 1 Diagnoses among the subjects. No Progesterone progesterone P N [ 219 n [ 216 value Tubal factor Endometriosis Unexplained infertility Male factor infertility
34 (15.5%) 16 (7.3%) 96 (43.8%) 73 (33.3%)
33 (15.3%) 7 (3.2%) 96 (44.4%) 80 (37.0%)
.9430 .0929 .9750 .4787
Note: Statistical analysis was performed by using chi-square tests; P< .05 was considered statistically significant. Bjuresten. Progesterone and live birth rate. Fertil Steril 2011.
Pregnancy Outcome The live birth rate was significantly higher in the group receiving progesterone than in the group that did not receive it: 30% versus 20%, P¼.0272. There were no statistically significant differences in the early miscarriage rate, clinical pregnancy rate, or spontaneous abortion rate between the two groups (Table 2).
DISCUSSION In the present study the live birth rate was significantly higher in women receiving progesterone compared with those women who did not. Progesterone is essential, not only for endometrial development, but possibly also for the developing embryo, through regulation of the immune system (7, 8). Increasing evidence shows the importance of a high-quality endometrium for successful implantation. Ovarian stimulation alters endometrial gene expression (2, 9), but whether or not there is a difference in gene expression in natural cycles compared with artificial cycles is, to the best of our knowledge, not known. Circulating levels of progesterone vary between individual women, and it seems to be the rise in progesterone
during the luteal phase, rather than a specific level, that determines endometrial receptivity (8). It has previously been shown that the implantation rate is higher in natural cycles than in artificial cycles, but no difference in live birth rate has been shown (10). High progesterone levels in artificial cycles have resulted in a higher clinical pregnancy rate (5). The women in the present study had normal ovulatory function, as shown by ultrasonographic scans. Their diagnoses were unexplained infertility, tubal factor infertility, male factor infertility, and endometriosis. Those with endometriosis were initially excluded from the study, because the diagnosis was changed during treatment from unexplained infertility to endometriosis. However, as it can be assumed that these women had ovulatory menstrual cycles, they were included in the analysis. Laparoscopy is not a routine diagnostic procedure in our clinic, and it can therefore be assumed that some women with unexplained infertility might have endometriosis. Women who were later found to have ovulatory dysfunction were excluded from data analysis. There was no difference in the distribution of diagnoses between the two groups. The numbers of grade A and grade B embryos were similar in the two groups. Likewise, the distribution of IVF and intracytoplasmic sperm injection embryos was comparable in the two groups. It can therefore be concluded that in this study, the influence of progesterone on the endometrium and on the implantation process can explain the higher live birth rate in the treatment group. Natural progesterone is rapidly metabolized after oral administration. Micronized progesterone is of reduced particle size and has increased bioavailability (11, 12), and is therefore used routinely in our clinic. The route of administration of progesterone is important, and the vaginal route is preferred to intramuscular administration (13, 14). It has been shown that vaginal progesterone induces adequate endometrial development, despite low serum progesterone concentrations (15–17). Vaginally administered progesterone increases serum concentrations to a peak level after approximately 8 hours, and thereafter there is a gradual fall during the next 8 hours (18). Therefore, progesterone was given twice a day.
TABLE 2 Pregnancy outcome in the two treatment groups.
No. of transfers No. of embryos transferred No. of embryos transferred (mean) No. of single embryo transfers No. of transfers with good-quality embryos No. of transfers with lower-quality embryos No. of blastocyst transfers No. of IVF transfers No. of ICSI embryos Positive hCG rate Miscarriage rate Clinical pregnancy rate Clinical abortion rate Live birth rate (at least one live infant)
Progesterone
No progesterone
n ¼ 219 n ¼ 290 n ¼ 1.32 n ¼ 148 n ¼ 164 n ¼ 126 n¼3 n ¼ 110 n ¼ 109 0.35 (76 of 219) 0.03 (7 of 219) 0.32 (69 of 219) 0.02 (4 of 219) 0.30 (65 of 219)
n ¼ 216 n ¼ 293 n ¼ 1.36 n ¼ 139 n ¼ 178 n ¼ 116 n¼9 n ¼ 105 n ¼ 112 0.28 (60 of 216) 0.03 (6 of 216) 0.25 (54 of 216) 0.05 (10 of 216) 0.20 (44 of 216)
P value .8921 .9067 — .5423 .3706 .3706 .1497 .7728 .7728 .1458 .7977 .1614 .1105 .0272*
Note: Statistical evaluation was performed by using chi-square tests. ICSI ¼ intracytoplasmic sperm injection. *a value of P< .05 was considered significant. Bjuresten. Progesterone and live birth rate. Fertil Steril 2011.
536
Bjuresten et al.
Progesterone and live birth rate
Vol. 95, No. 2, February 2011
Vaginal administration seems to result in better steady-state serum progesterone levels compared with intramuscular and oral administration, and higher implantation rates have been seen after vaginal compared with oral progesterone in GnRH agonist cycles (19). This is in line with the results of the present study. One disadvantage of the present study is that it was not double blind. The reason for this is that placebo was not avail-
able, owing to the high cost of production. A strength of the study is that the women were randomly allocated to either the progesterone or the no-progesterone group by using opaque sealed envelopes. In conclusion, we have shown that additional progesterone as luteal phase support in women undergoing frozen-thawed embryo transfers in natural cycles is beneficial.
REFERENCES 1. Veleva Z, Karinen P, Tomas C, Tapanainen JS, Martikainen H. Elective single embryo transfer with cryopreservation improves the outcome and diminishes the costs of IVF/ICSI. Hum Reprod 2009;24:1632–9. 2. Haouzi D, Assou S, Mahmoud K, Tondeur S, Reme T, Hedon B, et al. Gene expression profile of human endometrial receptivity: comparison between natural and stimulated cycles for the same patients. Hum Reprod 2009;24:1436–45. 3. Critchley HO, Saunders PT. Hormone receptor dynamics in a receptive human endometrium. Reprod Sci 2009;16:191–9. 4. Csapo AI, Pulkkinen MO, Ruttner B, Sauvage JP, Wiest WG. The significance of the human corpus luteum in pregnancy maintenance. I. Preliminary studies. Am J Obstet Gynecol 1972;112:1061–7. 5. Orvieto R, Meltcer S, Volodarski M, Scharf S, Rabinson J, Zohav E, et al. Luteal phase support for patients undergoing frozen-thawed embryo transfer cycles—the required progesterone dose. Clin Exp Obstet Gynecol 2007;34: 25–6. 6. Mui Lam P, Chun Cheung M, Ping Cheung L, Ingrid Lok H, John Haines C. Effects of early luteal-phase vaginal progesterone supplementation on the outcome of in vitro fertilization and embryo transfer. Gynecol Endocrinol 2008;24: 674–80.
Fertility and Sterility
7. Szekeres-Bartho J, Wilczynski JR, Basta P, Kalinka J. Role of progesterone and progestin therapy in threatened abortion and preterm labour. Front Biosci 2008;13:1981–90. 8. Stavreus-Evers A, Nikas G, Sahlin L, Eriksson H, Landgren BM. Formation of pinopodes in human endometrium is associated with the concentrations of progesterone and progesterone receptors. Fertil Steril 2001;76:782–91. 9. Koler M, Achache H, Tsafrir A, Smith Y, Revel A, Reich R. Disrupted gene pattern in patients with repeated in vitro fertilization (IVF) failure. Hum Reprod 2009;24:2541–8. 10. Gelbaya TA, Nardo LG, Hunter HR, Fitzgerald CT, Horne G, Pease EE, et al. Cryopreserved-thawed embryo transfer in natural or down-regulated hormonally controlled cycles: a retrospective study. Fertil Steril 2006;85:603–9. 11. Maxson WS, Hargrove JT. Bioavailability of oral micronized progesterone. Fertil Steril 1985;44:622–6. 12. Kimzey LM, Gumowski J, Merriam GR, Grimes GJ Jr, Nelson LM. Absorption of micronized progesterone from a nonliquefying vaginal cream. Fertil Steril 1991;56:995–6. 13. Lan VT, Tuan PH, Canh LT, Tuong HM, Howles CM. Progesterone supplementation during cryopreserved embryo transfer cycles: efficacy and convenience of two vaginal formulations. Reprod Biomed Online 2008;17:318–23.
14. Khan N, Richter KS, Newsome TL, Blake EJ, Yankov VI. Matched-samples comparison of intramuscular versus vaginal progesterone for luteal phase support after in vitro fertilization and embryo transfer. Fertil Steril 2009;91:2445–50. 15. Salat-Baroux J, Cornet D, Alvarez S, Antoine JM, Tibi C, Mandelbaum J, et al. Pregnancies after replacement of frozen-thawed embryos in a donation program. Fertil Steril 1988;49:817–21. 16. Cicinelli E, Borraccino V, Petruzzi D, Mazzotta N, Cerundolo ML, Schonauer LM. Pharmacokinetics and endometrial effects of the vaginal administration of micronized progesterone in an oilbased solution to postmenopausal women. Fertil Steril 1996;65:860–2. 17. Fanchin R, De Ziegler D, Bergeron C, Righini C, Torrisi C, Frydman R. Transvaginal administration of progesterone. Obstet Gynecol 1997;90: 396–401. 18. Nillius SJ, Johansson ED. Plasma levels of progesterone after vaginal, rectal, or intramuscular administration of progesterone. Am J Obstet Gynecol 1971;110:470–7. 19. Buvat J, Marcolin G, Guittard C, Herbaut JC, Louvet AL, Dehaene JL. Luteal support after luteinizing hormone-releasing hormone agonist for in vitro fertilization: superiority of human chorionic gonadotropin over oral progesterone. Fertil Steril 1990;53:490–4.
537
Objective: To see if progesterone support has a beneficial effect on live birth rate after frozen embryo transfer in natural cycles. Design: Prospective randomized controlled trial. Setting: University-based hospital. Subject(s): Four hundred thirty-five women undergoing embryo transfer in natural cycles. Intervention(s): The women received either vaginal progesterone, 400 mg twice a day from the day of embryo transfer in natural cycles, or no progesterone support. Main Outcome Measure(s): Live birth rate, biochemical pregnancy rate, pregnancy rate, and spontaneous abortion rate. Result(s): Live birth rate were significantly greater in women receiving vaginal progesterone as luteal phase support after frozen–thawed embryo transfer in natural cycles compared with those who did not take progesterone. There were no differences in biochemical pregnancy rate, pregnancy rate, or spontaneous abortion rate. Conclusion(s): Progesterone supplementation improves live birth rate after embryo transfer in natural cycles. (Fertil Steril 2011;95:534–7. 2011 by American Society for Reproductive Medicine.) Key Words: Progesterone, pregnancy rate, live birth rate, frozen embryo transfer, natural menstrual cycle
Single-embryo transfer has become standard procedure to avoid multiple pregnancies in in vitro fertilization (IVF) and embryo transfer. Recently, it was shown that single-embryo transfer in combination with cryopreservation is more effective as regards cumulative birth rate, more cost-effective, and results in a lower number of twins than double-embryo transfer (1). Furthermore, the receptiveness of the endometrium is seriously compromised by controlled ovarian stimulation protocols (2). Therefore, transfer of frozen–thawed embryos in natural cycles is a preferred choice for women with normal ovulatory menstrual cycles. Progesterone is a prerequisite for development of the endometrium and implantation of an embryo. Transformation of the endometrium to a receptive phase depends on adequate progesterone exposure in addition to preceding estrogen priming (3). Low levels of circulating progesterone during early pregnancy may result in miscarriage (4). In women with proven fertility, production of progesterone from the corpus luteum is sufficient to support the endometrium and facilitate implantation. There is little controlled data regarding the need of progesterone supplementation if an embryo is transferred during a natural cycle to an infertile woman, and there is no consensus about the possible benefits of progesterone supplementation. There are varying practices among clinics; some offer supplementation with progesterone after embryo transfer in natural cycles, whereas others do not. Generally, there is a belief that endogenous
Received February 15, 2010; revised May 5, 2010; accepted May 6, 2010; published online June 26, 2010. K.B. has nothing to disclose. B.-M.L. has nothing to disclose. O.H. has nothing to disclose. A.S.-E. has nothing to disclose. Reprint requests: Anneli Stavreus-Evers, Ph.D., Department of Women’s and Children’s Health, Uppsala University Hospital, 751 85 Uppsala, Sweden (FAX: 46 8 18 55 97 75; E-mail: Anneli.Stavreus-Evers@kbh. uu.se).
534
production of progesterone is sufficient to support implantation in a natural cycle. Beneficial effects of high doses of progesterone after frozen embryo transfer in artificial cycles were shown by Orvieto et al. (5). In another report, after fresh embryo transfer there was no effect on pregnancy and implantation rates among women receiving micronized progesterone as luteal phase supplementation (6). Frozen–thawed embryo transfer in a natural cycle is a different situation. The women involved are often subfertile, and they may have suboptimal endometria during their natural cycles. In view of the above, we designed a prospective randomized study to investigate if pregnancy rates could be improved with vaginal progesterone supplementation during the luteal phase and early pregnancy after frozen–thawed embryo transfer.
MATERIALS AND METHODS Subjects Women scheduled for frozen embryo transfer were asked to participate in the study. Four hundred thirty-five women agreed to participate, and were randomized to either vaginal micronized progesterone supplementation (n ¼ 219) or to no supplementation (n ¼ 216). The women included had been initially diagnosed with unexplained infertility, tubal factor infertility, or male factor infertility.
Ethics The Ethics Committee at Karolinska Institutet approved the study. There is no institutional review board at Karolinska Institutet. None of the investigators had any conflict of interest in relation to this study. Informed oral and written consent was obtained from all participating women.
Study Design The study was designed as a prospective randomized controlled trial. At the day of embryo transfer, the women were asked to participate in the study. They were randomly allocated to either the progesterone or the no-progesterone group. Allocation was performed by using opaque sealed
Fertility and Sterility Vol. 95, No. 2, February 2011 Copyright ª2011 American Society for Reproductive Medicine, Published by Elsevier Inc.
0015-0282/$36.00 doi:10.1016/j.fertnstert.2010.05.019
FIGURE 1 The number of women included in the study, and the numbers of positive hCG test results, early miscarriages, clinical pregnancies, spontaneous abortions, and deliveries are shown.
477 invited Excluded n=42 435 included
216 No progsterone
60 positive hCG
54 clinical pregnancy
44 deliveries
156 not pregnant
6 early miscarriage
219 Progesterone
143 not pregnant
76 positive hCG
7 early miscarriage
10 spontaneous abortions
69 clinical pregnancy
4 spontaneous abortions
65 deliveries
Bjuresten. Progesterone and live birth rate. Fertil Steril 2011.
envelopes. The study was an open trial, because it was not possible to obtain a placebo alternative to micronized progesterone. The study was not supported by any pharmaceutical company, and the hospital pharmacy could not produce the placebo needed. Power calculation showed that 213 subjects in each group were needed to detect a difference of 15% at the 80% level and an a value of 0.05.
Treatment The control women did not receive any hormone supplementation. The treated women received vaginal micronized progesterone, 400 mg twice a day, starting from the evening of the day of embryo transfer. A vaginal ultrasonographic scan was performed once for each woman included in the study, on cycle days 10 to 14. The ovaries were visualized and the diameter of the leading follicle was measured. On the day the leading follicle had reached 16 mm in diameter, the women started daily urine tests in the morning to detect the LH surge, using Clearblue digital ovulation tests (Swiss Precision Diagnostics GmbH, Bedford, UK). Three days after the LH surge, the embryo/embryos were thawed and embryo transfer was performed. Embryo transfer was performed using either a Sidney K-jets-7019 SIVF catheter (COOK, Queensland, Australia) or an Emtrac 4219 Delphin catheter (Gynetics Medical products N.V., Hamont-Achel, Belgium). One midwife (K.B.) transferred all the embryos.
Outcome Measures The main outcome measures were positive pregnancy test results, indicated as measurable serum human chorionic gonadotropin (hCG) concentrations, early miscarriage rate, clinical pregnancy rate, spontaneous abortions, and live birth rate.
Statistics Statistical evaluation was performed by using a chi-square test, with SPSS software (SPSS, Chicago, IL, USA).
Fertility and Sterility
Definitions The quality of embryos transferred was evaluated as either grade A, with all blastomeres intact, or grade B, with between 50% and 100% of blastomeres intact. Lower quality embryos were not transferred. Pregnancy was confirmed by a positive result in a urine hCG test conducted 18 days after frozen embryo transfer. The positive hCG rate was determined as the ratio between the number of positive hCG tests and the total number of transfers. The clinical pregnancy rate was defined as the number of cases with evidence of at least one gestational sac, divided by the number of transfers. The early miscarriage rate was defined as the number of early pregnancy losses divided by the total number of transfers. The clinical abortion rate was defined as the number of clinical pregnancy losses before the 20th week of gestation divided by the number of transfers. The live birth rate was the ratio of live births to embryo transfers.
RESULTS Study Subjects Of the initial 477 women invited to participate, 435 were included in the study. Forty-two women were excluded for the following reasons: 34 did not want to participate, 3 presented with ovarian dysfunction, 2 received a donated oocyte, 1 had cancer, 1 had rheumatoid arthritis, and 1 was excluded because she was already included in another study (Fig. 1). Women who were later found to have endometriosis were included in the data analysis. The distribution of diagnoses was similar in the two groups (Table 1). The women who did not want to participate in the study had negative experiences of previous use of progesterone. The mean age of the women in the progesterone group was 35.0 3.68 years, and the mean age of the women in the no-progesterone group was 34.2 3.56 years.
535
TABLE 1 Diagnoses among the subjects. No Progesterone progesterone P N [ 219 n [ 216 value Tubal factor Endometriosis Unexplained infertility Male factor infertility
34 (15.5%) 16 (7.3%) 96 (43.8%) 73 (33.3%)
33 (15.3%) 7 (3.2%) 96 (44.4%) 80 (37.0%)
.9430 .0929 .9750 .4787
Note: Statistical analysis was performed by using chi-square tests; P< .05 was considered statistically significant. Bjuresten. Progesterone and live birth rate. Fertil Steril 2011.
Pregnancy Outcome The live birth rate was significantly higher in the group receiving progesterone than in the group that did not receive it: 30% versus 20%, P¼.0272. There were no statistically significant differences in the early miscarriage rate, clinical pregnancy rate, or spontaneous abortion rate between the two groups (Table 2).
DISCUSSION In the present study the live birth rate was significantly higher in women receiving progesterone compared with those women who did not. Progesterone is essential, not only for endometrial development, but possibly also for the developing embryo, through regulation of the immune system (7, 8). Increasing evidence shows the importance of a high-quality endometrium for successful implantation. Ovarian stimulation alters endometrial gene expression (2, 9), but whether or not there is a difference in gene expression in natural cycles compared with artificial cycles is, to the best of our knowledge, not known. Circulating levels of progesterone vary between individual women, and it seems to be the rise in progesterone
during the luteal phase, rather than a specific level, that determines endometrial receptivity (8). It has previously been shown that the implantation rate is higher in natural cycles than in artificial cycles, but no difference in live birth rate has been shown (10). High progesterone levels in artificial cycles have resulted in a higher clinical pregnancy rate (5). The women in the present study had normal ovulatory function, as shown by ultrasonographic scans. Their diagnoses were unexplained infertility, tubal factor infertility, male factor infertility, and endometriosis. Those with endometriosis were initially excluded from the study, because the diagnosis was changed during treatment from unexplained infertility to endometriosis. However, as it can be assumed that these women had ovulatory menstrual cycles, they were included in the analysis. Laparoscopy is not a routine diagnostic procedure in our clinic, and it can therefore be assumed that some women with unexplained infertility might have endometriosis. Women who were later found to have ovulatory dysfunction were excluded from data analysis. There was no difference in the distribution of diagnoses between the two groups. The numbers of grade A and grade B embryos were similar in the two groups. Likewise, the distribution of IVF and intracytoplasmic sperm injection embryos was comparable in the two groups. It can therefore be concluded that in this study, the influence of progesterone on the endometrium and on the implantation process can explain the higher live birth rate in the treatment group. Natural progesterone is rapidly metabolized after oral administration. Micronized progesterone is of reduced particle size and has increased bioavailability (11, 12), and is therefore used routinely in our clinic. The route of administration of progesterone is important, and the vaginal route is preferred to intramuscular administration (13, 14). It has been shown that vaginal progesterone induces adequate endometrial development, despite low serum progesterone concentrations (15–17). Vaginally administered progesterone increases serum concentrations to a peak level after approximately 8 hours, and thereafter there is a gradual fall during the next 8 hours (18). Therefore, progesterone was given twice a day.
TABLE 2 Pregnancy outcome in the two treatment groups.
No. of transfers No. of embryos transferred No. of embryos transferred (mean) No. of single embryo transfers No. of transfers with good-quality embryos No. of transfers with lower-quality embryos No. of blastocyst transfers No. of IVF transfers No. of ICSI embryos Positive hCG rate Miscarriage rate Clinical pregnancy rate Clinical abortion rate Live birth rate (at least one live infant)
Progesterone
No progesterone
n ¼ 219 n ¼ 290 n ¼ 1.32 n ¼ 148 n ¼ 164 n ¼ 126 n¼3 n ¼ 110 n ¼ 109 0.35 (76 of 219) 0.03 (7 of 219) 0.32 (69 of 219) 0.02 (4 of 219) 0.30 (65 of 219)
n ¼ 216 n ¼ 293 n ¼ 1.36 n ¼ 139 n ¼ 178 n ¼ 116 n¼9 n ¼ 105 n ¼ 112 0.28 (60 of 216) 0.03 (6 of 216) 0.25 (54 of 216) 0.05 (10 of 216) 0.20 (44 of 216)
P value .8921 .9067 — .5423 .3706 .3706 .1497 .7728 .7728 .1458 .7977 .1614 .1105 .0272*
Note: Statistical evaluation was performed by using chi-square tests. ICSI ¼ intracytoplasmic sperm injection. *a value of P< .05 was considered significant. Bjuresten. Progesterone and live birth rate. Fertil Steril 2011.
536
Bjuresten et al.
Progesterone and live birth rate
Vol. 95, No. 2, February 2011
Vaginal administration seems to result in better steady-state serum progesterone levels compared with intramuscular and oral administration, and higher implantation rates have been seen after vaginal compared with oral progesterone in GnRH agonist cycles (19). This is in line with the results of the present study. One disadvantage of the present study is that it was not double blind. The reason for this is that placebo was not avail-
able, owing to the high cost of production. A strength of the study is that the women were randomly allocated to either the progesterone or the no-progesterone group by using opaque sealed envelopes. In conclusion, we have shown that additional progesterone as luteal phase support in women undergoing frozen-thawed embryo transfers in natural cycles is beneficial.
REFERENCES 1. Veleva Z, Karinen P, Tomas C, Tapanainen JS, Martikainen H. Elective single embryo transfer with cryopreservation improves the outcome and diminishes the costs of IVF/ICSI. Hum Reprod 2009;24:1632–9. 2. Haouzi D, Assou S, Mahmoud K, Tondeur S, Reme T, Hedon B, et al. Gene expression profile of human endometrial receptivity: comparison between natural and stimulated cycles for the same patients. Hum Reprod 2009;24:1436–45. 3. Critchley HO, Saunders PT. Hormone receptor dynamics in a receptive human endometrium. Reprod Sci 2009;16:191–9. 4. Csapo AI, Pulkkinen MO, Ruttner B, Sauvage JP, Wiest WG. The significance of the human corpus luteum in pregnancy maintenance. I. Preliminary studies. Am J Obstet Gynecol 1972;112:1061–7. 5. Orvieto R, Meltcer S, Volodarski M, Scharf S, Rabinson J, Zohav E, et al. Luteal phase support for patients undergoing frozen-thawed embryo transfer cycles—the required progesterone dose. Clin Exp Obstet Gynecol 2007;34: 25–6. 6. Mui Lam P, Chun Cheung M, Ping Cheung L, Ingrid Lok H, John Haines C. Effects of early luteal-phase vaginal progesterone supplementation on the outcome of in vitro fertilization and embryo transfer. Gynecol Endocrinol 2008;24: 674–80.
Fertility and Sterility
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