Controlled natural cycle IVF with antagonist use and blastocyst transfer

Does the use of gonadotropin-releasing hormone antagonists in natural IVF cycles for poor responder patients cause more harm than benefit?

Poor ovarian response to controlled ovarian stimulation (COS) is one of the most critical factors that substantially limits the success of assisted reproduction techniques (ARTs). Natural and modified natural cycle IVF are two options that could be considered as a last resort. Blocking gonadotropin-releasing hormone (GnRH) actions in the endometrium via GnRH receptor antagonism may have a negative impact on endometrial receptivity. We analysed IVF outcomes in 142 natural (n = 30) or modified natural (n = 112) IVF cycles performed in 82 women retrospectively. A significantly lower proportion of natural cycles reached follicular aspiration compared to modified natural cycles (56.7% vs. 85.7%, p < 0.001). However, the difference between the numbers of IVF cycles ending in embryo transfer (26.7% vs. 44.6%) was not statistically significant between natural cycle and modified natural IVF cycles. Clinical pregnancy (6.7% vs. 7.1%) and live birth rates per initiated cycle (6.7% vs. 5.4%) were similar between the two groups. Notably, the implantation rate was slightly lower in modified natural cycles (16% vs. 25%, p > 0.05). There was a trend towards higher clinical pregnancy (25% vs. 16%) and live birth (25% vs. 12%) rates per embryo transfer in natural cycles compared to modified natural cycles, but the differences did not reach statistical significance.

Natural cycle IVF: evaluation of 463 cycles and summary of the current literature

PURPOSE

Natural cycle (NC) IVF/ICSI has proven to be an alternative to conventional IVF/ICSI cycles.

METHODS

Within our retrospective, observational study (n = 159) infertile couples underwent (n = 463) cycles of NC-IVF/ICSI from May 2007 until December 2011. Oocyte pick-up was performed within a pure natural cycle excluding any hormonal stimulation except of hCG for ovulation induction. Oocytes were fertilized by IVF/ICSI and embryo transfer took place 2 or 3 days later. In addition, the current literature was analysed concerning pregnancy rates in NC-IVF/ICSI cycles.

RESULTS

Oocyte pick-up was performed in n = 463 NC and was successful in n = 342 cases (IVF n = 135, ICSI n = 207). 203 oocytes were fertilized (IVF n = 87, ICSI n = 116, FR 59.4 %) and lead to 192 embryo transfers. Finally, 25 pregnancies were reached (PR 13.0 % per transfer) resulting in four biochemical pregnancies, 7 (33.3 %) miscarriages, one pregnancy of unknown outcome and 13 live births. Within the current literature (n = 27 studies), PR in NC-IVF/ICSI cycles varied between 10.2 and 50 %.

CONCLUSIONS

Within our study, pregnancy rates in pure NC-IVF/ICSI remained below 15 %. Although this may be linked to unfavourable preconditions like patients' age >40 years, low ovarian reserve or long duration of infertility, further improvement is necessary to increase pregnancy rates.

IVF/ICSI outcomes after culture of human embryos at low oxygen tension: a meta-analysis

BACKGROUND

Improved pregnancy, implantation, and birth rates have been reported after the use of reduced O2 concentration during embryo culture, mainly due to a reduction of the cumulative detrimental effects of reactive oxygen species. However, some studies have failed to report any positive effects. The objective of this meta-analysis was to evaluate the effect of a low-O2 environment on IVF/intracytoplasmic sperm injection (ICSI) outcomes.

METHODS

All available published and ongoing randomised trials that compared the effects of low (~5%; OC~5) and atmospheric (~20%; OC~20) oxygen concentrations on IVF/ICSI outcomes were included. Search strategies included online surveys of databases from 1980 to 2011. The outcomes measured were fertilisation rate, implantation rate and ongoing pregnancy rates. The fixed effects model was used to calculate the odds ratio.

RESULTS

Seven studies were included in this analysis. The pooled fertilisation rate did not differ significantly (P=0.54) between the group of oocytes cultured at low O2 tension and the group at atmospheric O2 tension. Concerning all cycles, the implantation (P=0.06) and ongoing pregnancy (P=0.051) rates were not significantly different between the group receiving transferred sets containing only OC~5 embryos and the group receiving transferred sets with only OC~20 embryos. In a meta-analysis performed for only those trials in which embryos were transferred on day 2/3, implantation (P=0.63) and ongoing pregnancy (P=0.19) rates were not significantly different between the groups. In contrast, when a meta-analysis was performed using only trials in which embryos were transferred on days 5 and 6 (at the blastocyst stage), the group with transferred sets of only OC~5 embryos showed a statistically significantly higher implantation rate (P=0.006) than the group receiving transferred sets with only OC~20 embryos, although the ongoing pregnancy (P=0.19) rates were not significantly different between the groups.

CONCLUSIONS

Despite some promising results, it seems too early to conclude that low O2 culture has an effect on IVF outcome. Additional randomised controlled trials are necessary before evidence-based recommendations can be provided. It should be emphasised that the present meta-analysis does not provide any evidence that low oxygen concentration is unnecessary.

Embryo implantation rates in natural and stimulated assisted reproduction treatment cycles in poor responders

Controlled ovarian stimulation with exogenous gonadotrophins and gonadotrophin-releasing hormone (GnRH) analogues enables the collection of multiple oocytes and subsequent development of multiple embryos. However, interfering with the natural hormonal milieu may decrease the probability of successful embryo implantation due to effects on oocytes and/or endometrium. In order to provide a fair comparison of embryo implantation rates between natural cycles and stimulated cycles, bias caused by the presence of multiple embryos available for transfer in stimulated cycles should be avoided. This retrospective study analysed embryo implantation rates in cycles in which only a single embryo was available for transfer in 304 women who had poorly responded to ovarian stimulation in the previous cycle. Embryo implantation rates with different stimulation protocols were as follows: natural cycle, 20% (6/30); gonadotrophin only, 5.6% (3/54); long GnRH protocol, 3.8% (2/52); co-flare protocol, 1.9% (1/52); microdose flare-up, 15.4% (4/26); GnRH antagonists, 14.4% (13/90). Although the difference was not statistically significant there was a trend towards higher implantation rates with natural cycles in this group of women. Natural cycle IVF may be a reasonable and patient-friendly treatment choice yielding an acceptable outcome for women who are known or anticipated poor responders to ovarian stimulation.

Natural IVF cycles may be desirable for women with repeated failures by stimulated IVF cycles

PURPOSE

Although many reports support stimulated in vitro fertilization, several patients do not respond to it well. Furthermore, stimulated treatment could be associated with reduced ovarian response. We describe three successful cases involving patients of advanced age from whom dominant follicles were retrieved during the natural cycle.

MATERIALS AND METHODS

All patients had failed to bear children through stimulated in vitro fertilization. In case 1, a follicle was retrieved after a gonadotropin-releasing hormone agonist was used to induce luteinizing hormone surge. In cases 2 and 3, pregnancy was achieved via completely natural cycles.

RESULTS

One embryo was transferred every 16 cycles. Ongoing pregnancy--defined as pregnancy progressing beyond gestation week 9--was established in three cycles. The patients successfully delivered and had uneventful neonatal courses.

CONCLUSION

Mature oocyte retrieval followed by natural rather than stimulated in vitro fertilization might be a potential treatment for patients of advanced age when stimulated in vitro fertilization has been repeatedly unsuccessful.

Age, oestradiol and blastocysts can predict success in natural cycle IVF-embryo transfer

The aim of this study was to evaluate the influence of maternal age and oestradiol concentrations on blastocyst development and live birth rates in natural cycle IVF-embryo transfer. This observational study included 397 natural cycles with IVF embryo transfer for female infertility with embryo transfer on day 5. The cycles were divided into two groups according to the woman's age (<39 and > or = 39 years of age), and into two groups according to oestradiol concentrations on the day of human chorionic gonadotrophin (HCG) administration (0.4-0.49 nmol/l and 0.5-1.2 nmol/l). Comparison between the cycles in younger versus older age groups showed significant differences in blastocyst development rate, live birth rate per embryo transfer and live birth rate per cycle (55 versus 29%, 23 versus 3% and 13 versus 2% respectively) (P < 0.001). Comparison between cycles with lower versus higher oestradiol concentrations showed no significant differences in blastocyst development rate, live birth rate per embryo transfer and live birth rate per cycle (47 versus 49%, 18 versus 18%, and 11 versus 10% respectively). Advanced maternal age negatively predicts the success of natural cycle IVF, while low oestradiol concentrations on the day of HCG administration (ultrasound criteria fulfilled) do not negatively predict blastocyst development and success of natural cycle IVF.

Controlled natural cycle IVF: experience in a world of stimulation

A total of 134 controlled natural IVF (nIVF) cycles were reviewed retrospectively and compared with 370 stimulated IVF (sIVF) cycles. The clinical pregnancy rate per embryo transfer following nIVF was 27% and 47% in sIVF cycles for patients aged less than 35. However, natural cycle patients could attempt consecutive cycles with much less impact on their lives, both medically and financially. In patients under 35 years of age, the choice of controlled nIVF reduces the cost and risk to the patient, permitting her to have multiple, consecutive attempts, and cumulatively offers a clinical pregnancy rate which approaches that of sIVF. The multiple pregnancy rate in nIVF is significantly reduced compared with sIVF treatment cycles. In patients over 35 years of age the benefits of nIVF were much less evident (clinical pregnancy rate: 8% per embryo transfer) and the opportunity to transfer multiple embryos in these patients seems to be advantageous.

Luteal hormonal profile of oocyte donors stimulated with a GnRH antagonist compared with natural cycles

The effect of gonadotrophin-releasing hormone (GnRH) antagonist treatment on luteal phase hormonal profile has not yet been fully investigated. Cycle characteristics of 23 fertile donors stimulated with recombinant FSH and the GnRH antagonist, ganirelix 0.25, for IVF and receiving no kind of luteal supplementation were compared with control, natural cycles. Luteal luteinizing hormone (LH) serum concentrations as well area under the curve (AUC) for LH were significantly higher in natural cycles. In addition, luteal phase length was longer in natural cycles compared with donor cycles. Luteinizing hormone values dropped in the luteal phase of the stimulated cycles, with the lowest values being observed in the mid-luteal phase. AUC for progesterone in the luteal phase was significantly higher in the stimulated cycles compared with natural cycles (P < 0.001). Low LH serum concentrations and shortened luteal phase indicate the need for luteal phase supplementation in GnRH antagonist IVF cycles.