Oocyte stimulation parameters influence the number and proportion of mature oocytes retrieved in assisted reproductive technology cycles

Influencing factors and effects of low oocyte retrieval in patients with polycystic ovary syndrome undergoing in-vitro fertilization

OBJECTIVE

To investigate influencing factors and effects of low oocyte retrieval in patients with polycystic ovary syndrome (PCOS) undergoing in-vitro fertilization (IVF).

METHODS

In total, 720 patients with PCOS undergoing IVF were enrolled in this retrospective study from January 2017 to December 2022. The oocyte retrieval rate (ORR) was defined as the ratio of the number of oocytes retrieved to the number of follicles ≥ 12 mm in diameter on the trigger day. Using 1 standard deviation from the mean ORR as the boundary value, patients were divided into low and normal ORR groups. Patient characteristics, stimulation protocols, serum hormone levels, oocyte maturity, embryo developmental quality, and pregnancy outcomes of fresh transfer cycles were analysed.

RESULTS

ORR ranged from 0.06 to 2.69, with a mean value of 1.02. Compared with the normal ORR group (ORR ≥ 0.65), patients in the low ORR group (ORR < 0.65) had a higher body mass index; higher antral follicle count (AFC); more days of gonadotrophin stimulation; and lower serum oestradiol (E2) level, lower progesterone level and lower E2 level/follicle (≥12 mm) on the trigger day. Multivariate logistic regression analysis showed AFC [adjusted odds ratio (aOR) 1.05, 95 % confidence interval (CI) 1.0120-1.0940], E2 level/follicle (≥12 mm) (aOR 0.99, 95 % CI 0.9888-0.9972) and progesterone level (aOR 0.41, 95 % CI 0.2402-0.6649) on the trigger day were significantly associated with low ORR. Receiver operator characteristic curve analyses revealed that serum E2 level/follicle (≥12 mm) had an area under the curve of 0.7036 (95 % CI 0.65-0.76; p < 0.01). The cut-off value was 169.2 pg/ml, with sensitivity of 65 % and specificity of 65 %, for predicting low ORR. Low ORR was associated with fewer top-quality embryos and more cycles with no embryos available for transfer. The rates of metaphase II oocytes, top-quality embryos, clinical pregnancy and live birth did not differ between the two groups.

CONCLUSION

Serum E2 level/follicle (≥12 mm) on the trigger day may be used as a predictive factor for low ORR in patients with PCOS. Low ORR may not affect oocyte and embryo developmental potential under appropriate ovarian stimulation management, but likely increases the risk of no embryos being available for transfer.

Exploring gonadotropin dosing effects on MII oocyte retrieval in ovarian stimulation

PURPOSE

Ovarian stimulation with gonadotropins is crucial for obtaining mature oocytes for in vitro fertilization (IVF). Determining the optimal gonadotropin dosage is essential for maximizing its effectiveness. Our study aimed to develop a machine learning (ML) model to predict oocyte counts in IVF patients and retrospectively analyze whether higher gonadotropin doses improve ovarian stimulation outcomes.

METHODS

We analyzed the data from 9598 ovarian stimulations. An ML model was employed to predict the number of mature metaphase II (MII) oocytes based on clinical parameters. These predictions were compared with the actual counts of retrieved MII oocytes at different gonadotropin dosages.

RESULTS

The ML model provided precise predictions of MII counts, with the AMH and AFC being the most important, and the previous stimulation outcome and age, the less important features for the prediction. Our findings revealed that increasing gonadotropin dosage did not result in a higher number of retrieved MII oocytes. Specifically, for patients predicted to produce 4-8 MII oocytes, a decline in oocyte count was observed as gonadotropin dosage increased. Patients with low (1-3) and high (9-12) MII predictions achieved the best results when administered a daily dose of 225 IU; lower and higher doses proved to be less effective.

CONCLUSIONS

Our study suggests that high gonadotropin doses do not enhance MII oocyte retrieval. Our ML model can offer clinicians a novel tool for the precise prediction of MII to guide gonadotropin dosing.

The Prediction of IVF Outcomes with Autologous Oocytes and the Optimal MII Oocyte/Embryo Number for Live Birth at Advanced Maternal Age

Background and Objectives: Delayed childbearing in advanced age might be associated with a low prognosis for achieving pregnancy. Therefore, it is important to establish a predictive tool that will optimize the likelihood of a live birth at advanced age. Material and Methods: The retrospective study was conducted at the Ferona Fertility Clinic in Novi Sad (Republic of Serbia), between January 2020 and May 2021. The survey included 491 women aged ≥35 who met the inclusion criteria and who were subjected to an IVF (in vitro fertilization) treatment cycle. Results: The average number of retrieved oocytes, MII (metaphase II) oocytes, and developed embryos significantly decreased in advanced age. Age was also found to have a significant adverse effect on pregnancy and live birth rates. In women aged ≥35, 10/12 MII oocytes or 10/11 embryos are required for reaching an optimal live birth rate/cumulative live birth rate. Optimal CLBR (cumulative live birth rate) per one oocyte was achieved when 9 MII oocyte were retrieved. Conclusions: The study indicates that the cut-off for increased risk is ≥42 year. However, despite low live birth rates, autologous IVF for these women is not futile. An increase in the number of retrieved mature oocytes and a generation of surplus cryopreserved embryos could reinforce LBR (live birth rate) and CLBR. Clinicians should be very cautious in counseling, as autologous IVF may only be applicable to women with good ovarian reserve.

Maternal age and gonadotrophin elevation cooperatively decrease viable ovulated oocytes and increase ootoxicity, chromosome-, and spindle-misalignments: '2-Hit' and 'FSH-OoToxicity' mechanisms as new reproductive aging hypotheses

While there is consensus that advanced maternal age (AMA) reduces oocyte yield and quality, the notion that high FSH reduces oocyte quality and causes aneuploidy remains controversial, perhaps due to difficulties controlling the confounding variables of age and FSH levels. Here, contributions of age and gonadotrophin elevation were separately controlled using a mouse model of human female reproductive aging. Ovulated oocytes were collected from young and midlife mice after 0-, 2.6-, or 17-day treatment with the FSH analog equine chorionic gonadotrophin (eCG), to model both exogenous FSH elevation within a single treatment cycle (as in controlled ovarian stimulation (COS)), and chronic endogenous FSH elevation during multiple cycles (as in diminished ovarian reserve). After 17-day eCG, fewer total oocytes/mouse are ovulated in midlife than young mice, and a precipitous decline in viable oocytes/mouse is observed in midlife but not young mice throughout eCG treatment. eCG is potently ootoxic to ovulatory oocytes and strongly induces chromosome- and spindle-misalignments within 2.6 days of eCG in midlife, but only after 17 days in young mice. These data indicate that AMA increases susceptibility to multiple adverse effects of elevated FSH activity in ovulated oocytes, including declines in total and viable oocytes/mouse, and induction of ootoxicity and aneuploidy. Two hypotheses are proposed for underlying causes of infertility in women. The FSH OOToxicity Hypothesis ('FOOT Hypothesis') posits that high FSH is ootoxic to ovulatory oocytes and that FSH ootoxicity is a root cause of low pregnancy success rates in naturally cycling women with high FSH and IUI patients undergoing COS. The '2-Hit Hypothesis' posits that AMA increases susceptibility to FSH-induced ootoxicity and aneuploidy.