The Physiological Limits of Ovarian Stimulation Is it the seed or the soil? Arthur Leader, MD, FRCSC
Objectives 1. To consider how ovarian stimulation protocols work in IVF 2. To review the key events in follicular development in IVF 3. To review the impact of controlled ovarian hyperstimulation protocols for poor responders on the oocyte and endometrium
Pregnancy requires: Implantation of a developmentally competent embryo into a receptive endometrium
1980 s hmg Clomiphene Stimulation protocols in IVF 2 2 2 2 2 hcg or LH surge 1 3 5 7 9 11 13 15 17 OPU ET (1,2) 1990 s hmg/ufsh 2-3 2-3 2-3 2-3 2-3 Agonist LH E 2 USS Daily s.c./i.n. dose hcg 15 17 19 21 23 25 27 M 3 5 7 9 11 13 E 2 USS LH OPU ET(2) ET(3)
2000 s rfsh Antagonist Vag P4 Stimulation protocols in IVF 150-225 IU hcg 250 mcg 1 3 5 7 9 11 13 15 17 E 2 /USS OPU ET(3) ET(5) 2010 s SR-FSH Antagonist rfsh Vag P4 hcg 250 mcg 100-200 IU 1 3 5 7 9 11 13 15 17 E 2 /USS OPU ET(3) ET(5)
Wave theory of follicle development
Growth of follicles and attrition in vitro Levéillé, M-C, Ottawa Fertility Centre
Levéillé, M-C, Ottawa Fertility Centre
Attrition from COC to good blastocyst Ottawa Fertility Centre, unpublished data, 2010
Attrition at each Step % reaching the stage of a good morphology blastocyst COC 19% MII 22% 2PN 29% Good D3 embryo 38% Good D4 embryo 60% Good D3 embryo: at least 5-cell, at least grade 3, not blocked, no multinucleation Good D4 embryo: at least compacting, at least grade 3, not blocked, no multinucleation Ottawa Fertility Centre, unpublished data, 2010
IVF outcome in relation to number of Fertilization rates oocytes collected 1-3 eggs 4 6 eggs 7-10 eggs 11- -15 eggs > 15 eggs 56% 54% 55% 57% 54% Chance of ET 71.3% a 91.3% a 95.3% a 97.2% a 96.9% a Blastocyst ET 0.5%* 3.4%* 13.8%* 30.2%* 41.6%* Pregnancy rates 13.3 a 24.6% a 33.4% a 38.2% a 41.9% a No significant increase clinical pregnancy rates if more than six eggs collected Data for 4701 treatment cycles Hamoda, Sunkara, Khalaf, Braude and El-Toukhy, O-120, ESHRE 2010
What is the optimal protocol for IVF therapy? Hinges on probability of live birth Current estimates of live birth probabilities: based mainly on age, adjusted for other factors using semiquantitative scoring systems
Deep phenotyping to predict live birth outcome in IVF Boosted tree analysis stratifies patients according to clinical profiles Deep phenotyping : sorts patients into subsets defined by similar clinical characteristics uses data known prior to and during 1 st IVF cycle generates model to predict live birth probabilities in next cycle 1000 times more accurate than age-based approach PNAS 2010 107 (31) 13570-13575
Highly significant predictors of a live birth in an IVF cycle (p<0.001) Positive predictors PCOS* Endometrial thickness Total # of oocytes % normal fertilization Total # embryos Ave # cells/ embryo % 8-cell embryos % embryos that are blasts % embryos that were frozen Ave # cells/transferred embryo Day 5 embryo transfer Negative predictors Age of patients* Diminished ovarian reserve* Total units of gonadotropins # arrested embryos at 4 cells Assisted hatching Deep phenotyping to predict live birth outcomes in IVF, Banerjee et al., PNAS, 2010
Prognostic factors and their relative influence in an IVF model PNAS 2010 107 (31) 13570-13575
Increased gonadotropin dose and IVF outcomes Fertility and Sterility 2008; 89:1694-1701
What about the poor responder? Expected Advanced maternal age Previous ovarian cystectomies (endometriosis) Documented low ovarian reserve Smoker Unexpected No internationally agreed upon definition: Poor follicular recruitment High dose of gonadotropins Low peak serum estradiol levels
Stimulation options for the poor responder in IVF Microdose flare protocol Estradiol- antagonist protocol Natural cycle
Optimal maximal dose: microdose flare protocol
Viable Pregnancy (IUP FH)/OPU 2009 % 55 50 45 40 35 30 25 20 15 10 5 0 <35 35-39 40-42 >42 Up to 300 IU FSH/day More than 300 IU FSH/day
Microdose flare vs. Estradiol/Antagonist for IVF in Young Poor Responders Patch protocol More IU s of gonadotropin Lower estradiol Better embryo quality
Growth hormone for poor responders in IVF Kolibiankis et al, Hum Reprod 2009
Day 2 vs. Day 3 Embryo Transfer in Poor Responders
Natural cycle IVF
Drop-out rates and natural cycle
Miscarriage rates Haadsma et al: RBM Online, 20 (2),191-200, 2010
Follicular Development We believe that achieving optimal conditions in the follicle at the time of oocyte recovery is one of the essential features in the establishment of pregnancy. Fishel, Edwards and Purdy : Murnau Symposium, June 2, 1982 What are the optimal conditions?
Overexposure to LH overexposure to LH during follicular development may be detrimental to fertilisation in vitro LH may act by either altering the steroid environment of the follicle or by causing premature oocyte maturation. Howles, MacNamee, Edwards, Goswamy, Steptoe: Lancet, Aug. 30, 1986 Could overexposure to FSH be detrimental as well?
The Menstrual Cycle Dighe et al. Clin biochem: 38(2), 2005, 175-179
Ovarian biochemistry basics Ovaries with large number of growing follicles stimulated by high circulating FSH will secrete more progesterone than single follicle with declining FSH Prior to ovulation, LH reduces circulating progesterone by promoting conversion of androgens estrogens by granulosa cells Highly suppressive doses of GnRH agonists / antagonists increase dose requirements for FSH and profoundly suppress LH levels
FSH doses and the follicle High follicular FSH concentrations: Cause inappropriate cumulus cell differentiation Leading to poor egg developmental competence Possibly altered oocyte-cumulus cell gene expression
Experimental model
Effect of FSH doses on gene expression during in vitro antral follicle growth Three levels of FSH: control, decreasing, high At all levels: antral development, oocyte diameter and meiotic resumption were equal Progesterone production increased in the high-fsh group Normal decline in oocyte Bmp15 and Gdf9 prevented in high-fsh group Abnormal cumulus cell differentiation and functionality occurred in high-fsh group Sanchez, Adriaenssens, Romero, Smitz: Biol Reprod 83, 514-24, 2010
Implantation Most of the steps involved in establishing pregnancies by in vitro fertilization have largely been mastered.the major difficulty that remains concerns the proportion of embryos which implant, which is depressingly low Implantation rates for single embryo: 36.8% vs. 23.2% (natural vs. stimulated) [Table VIII] Edwards and Steptoe: Lancet 3 December, 1983 How do our stimulations affect implantation?
Stimulation and the endometrium All protocols affect endometrial receptivity when compared to the natural cycle GnRH antagonist protocols are more similar to natural cycle receptivity than agonist protocols Luteal support with progesterone +/- estrogen significantly alters expression of ECM protein and adhesion molecule genes
Percentage of genes in common: stimulated and natural cycles in the receptive endometrium Haouzi D et al. Biol Reprod 2010;82:679-686
In Conclusion Predictive models may help us to better adjust protocols to the patient For the normal responder, lower gonadotropin dosing appears to be best For the poor responder we are caught between the need to get 6 eggs and the high doses required to get there Growth hormone may assist in our stimulations Our protocols and supplements impact not only the follicle but also the endometrium in ways we have yet to discover