Does progesterone elevation compromise pregnancy rates in high responders? Insufficient evidence to draw a conclusion

Letrozole supplementation during controlled ovarian stimulation in expected high responders: a pilot randomized controlled study

BACKGROUND

Almost all of the previous studies related with co-administration of letrozole in IVF cycles were performed in poor responders and letrozole may reduce the total gonadotropin dose required for ovarian stimulation, and the pregnancy rate did not decrease in poor responders. This study aimed to assess whether high responders co-treatment with letrozole reduced supraphysiological late follicular phase estradiol levels and the incidence of premature progesterone elevated at the end of the follicular phase, thereby impacting positively on endometrial receptivity.

METHODS

A randomized parallel controlled study in a university-affiliated center include 130 high responders between October 2015 and August 2016. The patients were randomized on the first stimulation day of the IVF cycle and from stimulation day 5 receive letrozole (group A) or without letrozole treatment (group B).

RESULTS

Although estradiol levels were significantly lower in the letrozole group (group A) (P < 0.001), progesterone elevation (> 1.5 ng/mL was considered as a rise) on the day of hCG triggering (15.4, 7.7%) was not statistically significant (P = 0.170). RecFSH, the recovery rate of eggs, the high-quality embryo rate, and the thickness of endometrium (P = 0.776) were similar between the letrozole group(group A) and control groups (group B). Clinical pregnancy rates were 53.1% (26/49) and 72.9% (35/48) in the letrozole and control groups, respectively, with a statistical significance (P = 0.043).Live birth rates were 42.9% (21/49) and 62.5% (30/48),showed a marginally significant difference (P = 0.053). The miscarriage rate did not significantly differ between the two groups.

CONCLUSIONS

In this pilot study, letrozole supplementation could not reduce the incidence of premature progesterone rise during the late follicular phase in stimulated in vitro fertilization cycles in expected high responders, producing a harmful effect on the pregnancy outcome.

TRIAL REGISTRATION

China Clinical Trial Registration Center: ChiCTR-IPR-15006211 URL of the trial registry record: http://www.chictr.org.cn/showproj.aspx?proj=10731 . Trial registration date: 8 April, 2015. Date of first patient's enrolment: 5 October, 2015.

The slow growing embryo and premature progesterone elevation: compounding factors for embryo-endometrial asynchrony

STUDY QUESTION

Is there an association of progesterone (P₄) on the day of trigger with live birth in autologous ART transfer cycles on day 5 versus day 6?

SUMMARY ANSWER

P₄ had a greater negative effect on live birth in day 6 fresh transfers compared to day 5 fresh transfers.

WHAT IS KNOWN ALREADY

Premature P₄ elevation is associated with lower live birth rates in fresh autologous ART cycles, likely due to worsened endometrial-embryo asynchrony. Few studies have evaluated whether the effect of an elevated P₄ on the day of trigger is different on live birth rates with a day 5 compared to a day 6 embryo transfer.

STUDY DESIGN SIZE, DURATION

This was a retrospective cohort study with autologous IVF cycles with fresh embryo transfers on day 5 and day 6 from 2011 to 2014. A total of 4120 day 5 and 230 day 6 fresh autologous embryo transfers were included. The primary outcome was live birth, defined as a live born baby at 24 weeks gestation or later.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients from a large private ART practice were included. Analysis was performed with generalized estimating equations (GEE) modeling and receiver operating characteristic (ROC) curves.

MAIN RESULTS AND THE ROLE OF CHANCE

Day 6 transfers were less likely to have good quality embryos (73% versus 83%, P < 0.001) but the cohorts had similar rates of blastocyst stage transfer (92% versus 91%, P = 0.92). Live birth was less likely in fresh day 6 versus day 5 embryo transfers (34% versus 46%, P = 0.01) even when controlling for embryo confounders. In adjusted GEE models, the effect of P₄ as a continuous variable on live birth was more pronounced on day 6 (P < 0.001). Similarly, the effect of P₄ > 1.5 ng/ml on day of trigger was more pronounced on day 6 than day 5 (P < 0.001). Day 6 live birth rates were 8% lower than day 5 when P₄ was in the normal range (P = 0.04), but became 17% lower when P₄ was > 1.5 ng/ml (P < 0.01). ROC curves for P₄ predicting live birth demonstrated a greater AUC in day 6 transfers (AUC 0.59, 95% CI 0.51-0.66) than day 5 (AUC 0.54, 95% CI 0.52-0.55). Interaction testing of P₄ × day of embryo transfer was highly significant (P < 0.001), further suggesting that the effect of P₄ was more pronounced on day 6 embryo transfer. In fresh oocyte retrieval cycles with elevated P₄, a subsequent 760 frozen-thaw transfers did not demonstrate a difference between embryos that were frozen after blastulation on day 5 versus 6.

LIMITATIONS REASONS FOR CAUTION

Limitations include the retrospective design and the inability to control for certain confounding variables, such as thaw survival rates between day 5 and day 6 blastocysts. Also, the data set lacks the known ploidy status of the embryos and the progesterone assay is not currently optimized to discriminate between patients with a P₄ of 1.5 versus 1.8 ng/ml.

WIDER IMPLICATIONS OF THE FINDINGS

This study suggests further endometrial-embryo asynchrony when a slow growing embryo is combined with an advanced endometrium, ultimately leading to decreased live births. This suggests that premature elevated P₄ may be a factor in the lower live birth rates in day 6 fresh embryo transfers. Further studies are needed to evaluate if a frozen embryo transfer cycle can ameliorate the effect of elevated P₄ on the day of trigger among these slower growing embryos that reach blastocyst staging on day 6.

STUDY FUNDING/COMPETING INTERESTS

No external funding was received for this study. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

Are good patient and embryo characteristics protective against the negative effect of elevated progesterone level on the day of oocyte maturation?

OBJECTIVE

To evaluate if an elevated progesterone (P) level on the day of human chorionic gonadotropin (hCG) administration is associated with a decrease in live-birth rate in patients with a good prognosis.

DESIGN

Retrospective cohort study.

SETTING

Large, private, assisted reproductive technology (ART) practice.

PATIENT(S)

One thousand six hundred twenty fresh autologous ART cycles.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Live-birth rate.

RESULT(S)

A total of 934 blastocyst and 686 cleavage-stage embryo transfer (ET) cycles were evaluated. Serum P levels were not associated with markers of oocyte or embryo quality, including fertilization, embryo stage at transfer, and embryos available for cryopreservation. Patient age, stage of ET, embryo quality, the number of embryos transferred, and P level on the day of hCG administration were all significantly associated with live birth. Higher P levels were associated with decreased odds of live birth for cleavage- and blastocyst-stage embryos, poor-fair and good-quality embryos, and poor- and high-responder patients. The nonsignificance of interaction tests of P levels with embryo stage, embryo quality, patient age, and ovarian response indicated that the relationship between P level and live birth was similar regardless of these factors.

CONCLUSION(S)

An elevated serum P level on the day of hCG administration was negatively associated with live birth, even in ETs with a good prognosis.