Comparison of the number of oocytes obtained after ovarian stimulation between Chinese and Caucasian women undergoing in vitro fertilization using a standardized stimulation regime.

BACKGROUND: In vitro fertilization (IVF) is a well-established method to treat various causes of infertility. Some previous retrospective studies suggested a lower ovarian response in Asian women compared to Caucasian women. However, the ovarian stimulation regimens were not standardized, potentially confounding the findings. The objective of this study is to compare the number of oocytes obtained after ovarian stimulation between Chinese and Caucasian women undergoing IVF using a standardized stimulation regimen. METHODS: This is a prospective cohort study conducted in two tertiary IVF units in Hong Kong, China and Sydney, Australia from October 2016 to August 2019. A total of 192 women aged 18-42 years with a body weight > 60 kg underwent IVF with a standard ovarian stimulation regimen of 150 micrograms corifollitropin alfa (Elonva®) followed by 200 IU follitropin beta (Puregon®) per day. The number of oocytes retrieved in Chinese women treated in the Hong Kong center was compared to that of Caucasian women treated in the Australian center. RESULTS: Serum AMH levels were similar between the two groups. Although women in the Chinese cohort were older and had a higher body mass index (BMI), longer duration of infertility and lower antral follicle count (AFC) than those in the Caucasian cohort in this study, no differences in the number of oocytes retrieved [11 (8-17) vs. 11 (6-17), p=0.29], total dosage and duration of stimulation and number of follicles aspirated were noted between the two ethnic cohorts. The peak estradiol level was greater in Chinese women than in Caucasian women. After controlling for age, BMI and AFC, ethnicity was a significant independent determinant of the number of oocytes obtained. CONCLUSIONS: Chinese women had a higher number of oocytes after ovarian stimulation using a standardized stimulation regimen compared with Caucasian women undergoing IVF after controlling for age, BMI, AFC and AMH despite presenting later after a longer duration of infertility. TRIAL REGISTRATION NUMBER: NCT02748278.

Is more better? A higher oocyte yield is independently associated with more day-3 euploid embryos after ICSI.

STUDY QUESTION: Is the number of oocytes retrieved after ovarian stimulation for ICSI independently associated with the number of day-3 euploid embryos (EE)? SUMMARY ANSWER: A larger oocyte yield is independently associated with more day-3 EE, although the expected benefit decreases significantly with advancing age. WHAT IS KNOWN ALREADY: Although traditionally ovarian stimulation aims at collecting more than one oocyte in order to increase the chance of pregnancy, there is evidence suggesting that excessive ovarian response leads to lower live birth rates. Whether a larger oocyte yield after ovarian stimulation is associated with the genetic composition of the resulting embryos and therefore with their reproductive potential is still largely unknown. STUDY DESIGN, SIZE, DURATION: This is a multi-centered retrospective cohort study analyzing 724 cycles of preimplantation genetic testing for aneuploidy (PGT-A) cycles using day-3 biopsy and array-comparative genomic hybridization between March 2011 and December 2016 in three laboratories. PARTICIPANTS/MATERIALS, SETTING, METHODS: The primary outcome measure was the number of EE on day-3. Statistical analysis was performed using the generalized estimating equations (GEE) framework and multivariate regression models to control for the clustered nature of the data while adjusting for potential confounders. MAIN RESULTS AND THE ROLE OF CHANCE: A multivariate regression GEE model including all significant population and stimulation characteristics as covariates as well as an interaction term between female age and number of oocytes revealed that the number of oocytes retrieved was still positively associated with the number of EE (coeff: +0.40, 95% CI: 0.24-0.56). The interaction term was highly significant (coeff: -0.01, P < 0.001) indicating an effect modifying role of female age on the association of oocytes retrieved with the number of EE. The number of oocytes retrieved was also positively associated with cumulative live birth rates (odds ratio: 1.07, 95% CI: 1.03-1.12). LIMITATIONS, REASONS FOR CAUTION: This study is retrospective and the presence of residual unknown bias cannot be excluded. Furthermore, the population analyzed in this study might not be completely representative of the general population undergoing ICSI. WIDER IMPLICATIONS OF THE FINDINGS: These results provide an explanatory mechanism for the recently published positive association between the number of oocytes retrieved and cumulative live birth rates. STUDY FUNDING/COMPETING INTEREST(S): CAV is supported by a NHMRC Early Career Fellowship (GNT1147154)/ No competing interests to declare.

Do Asian women do as well as their Caucasian counterparts in IVF treatment: Cohort study.

AIM: To evaluate if there is a difference in pregnancy rate between Asian and Caucasian women when they undergo in vitro fertilization (IVF). METHODS: This was a retrospective cohort study set in a private reproductive medicine clinic. The study consisted of a total of 2594 patients (Asian, n = 522; Caucasian, n = 2072) undergoing IVF managed by a single doctor over a 10 year period. The main outcome measures were clinical pregnancy rate and live birth rate. Logistic regression was used to control for confounding factors. RESULTS: Asian women achieved a significantly lower clinical pregnancy and live birth rate than their Caucasian counterparts, despite replacement of more embryos. This difference was not significant after controlling for age and duration of infertility. Despite higher doses of gonadotrophin, they achieved fewer oocytes and had resultant fewer embryos for transfer or cryopreservation. CONCLUSIONS: In a study designed to reduce the effect of confounding factors by looking at a large number of patients from a single IVF unit under the care of a single doctor, there does not appear to be a difference in IVF pregnancy rate as a result of race. Asian women tend to present for IVF treatment at a later age after having tried for a longer period of time and this contributes significantly to their lower pregnancy rate.

Preliminary Development and Engineering Evaluation of a Novel Cricothyrotomy Device.

Cricothyrotomy is one of the procedures used to ventilate patients with upper airway blockage. This paper examines the most regularly used and preferred cricothyrotomy devices on the market, suggests critical design specifications for improving cricothyrotomy devices, introduces a new cricothyrotomy device, and performs an engineering evaluation of the device's critical components. Through a review of literature, manufacturer products, and patents, four principal cricothyrotomy devices currently in clinical use were identified. From the review, the Cook™ Melker device is the preferred method of clinicians but the device has acknowledged problems. A new emergency needle cricothyrotomy device (ENCD) was developed to address all design specifications identified in literature. Engineering, theoretical, and experimental assessments were performed. In situ evaluations of a prototype of the new device using porcine specimens to assess insertion, extraction, and cyclic force capabilities were performed. The device was very successful in its evaluation. Further discussion focuses on these aspects and a comparison of the new device with established devices. The proposed emergency needle cricothyrotomy device performed very well. Further work will be pursued in the future with in-vitro and in-vivo with canine models demonstrates the capabilities of the ENCD.

Are there non-invasive markers in human oocytes that can predict pregnancy outcome?

Predictive criteria for selection of the best embryo for single embryo transfer remain elusive. This study aimed to determine if non-invasive markers in human oocytes, detectable using polarized light microscopy, can predict pregnancy outcome. Twenty-two pregnancy-producing oocytes from 19 patients had their morphological features compared with 30 oocytes from 19 age-matched patients whose transfer did not result in a pregnancy. Both pregnant and non-pregnant patients had similar numbers of oocytes collected (average: 11.9 +/- 2.8 versus 11.3 +/- 2.9) and similar fertilization rates (70.1% versus 69.6%). All embryos transferred were 4-cell cleavage-stage on day 2 with <10% fragmentation. Meiotic spindles were examined at 39-40 h following human chorionic gonadotrophin administration for spindle normality, length, density and angle from first polar body. There was a significant difference in spindle normality in oocytes in the pregnant patients compared with oocytes in the non-pregnant patients (100% versus 33%, P < 0.001). Spindle density was significantly higher in those oocytes resulting in pregnancy (3.0 +/- 1.23 nm versus 2.5 +/- 0.7 nm, P = 0.02). These oocyte markers may provide a useful non-invasive tool in the selection of the embryo most likely to produce a pregnancy.

Do age and extended culture affect the architecture of the zona pellucida of human oocytes and embryos?

Advanced female age and extended in vitro culture have both been implicated in zona pellucida (ZP) hardening and thickening. This study aimed to determine the influence of (i) the woman's age and (ii) prolonged in vitro culture of embryos on ZP thickness and density using non-invasive polarized light (LC-PolScope) microscopy. ZP thickness and density (measured as retardance) were determined in oocytes, embryos and blastocysts in women undergoing intracytoplasmic sperm injection (ICSI) in two age groups (older, > 38 years; younger, < or = 38 years). A total of 193 oocytes from 29 patients were studied. The younger group contained 100 oocytes and the older group 93 oocytes. The ZP was significantly thicker in metaphase II oocytes in the older group compared with the younger group (mean +/- SD: 24.1 +/- 2.5 microm vs 23.1 +/- 3.3 microm; p = 0.01) but ZP density was equal (2.8 +/- 0.7 nm). By day 2 of culture, embryos from the two groups had similar ZP thickness (22.2 +/- 2.2 microm vs 21.7 +/- 1.6 microm; p = 0.28) and density (2.9 +/- 0.7 nm vs 2.8 +/- 0.8 nm; p = 0.57). For the embryos cultured to blastocyst (older: n = 20; younger: n = 18) ZP thickness was similar in the two groups (19.2 +/- 2.7 microm vs 19.1 +/- 5.0 microm; p = 0.8) but thinner than on day 2. The older group had significantly denser ZP than the younger group (4.2 +/- 0.5 nm vs 3.3 +/- 1.0 nm, p < 0.01). Blastocysts from both groups had significantly denser ZP than their corresponding day 2 embryos (older: 4.2 +/- 0.5 nm vs 2.9 +/- 0.7 nm, p < 0.001; younger: 3.3 +/- 1.0 nm vs 2.8 +/- 0.8 nm, p = 0.013). It is concluded that there is little relationship between ZP thickness and its density as measured by polarized light microscopy. While ZP thickness decreases with extended embryo culturing, the density of the ZP increases. ZP density increases in both age groups with extended culture and, interestingly, more in embryos from older compared with younger women.