A new flow-based design for double-lumen needles.

Oocyte retrieval forms a crucial part of in vitro fertilisation treatment and its ultimate outcome. Standard double-lumen needles, which include a sequence of aspiration and flushing steps, are characterised by a similar success rate to single-lumen needles, despite their increased cost. A novel hydrodynamics-based needle called the OxIVF needle is proposed here, which is geared towards the generation of an internal flow field within the full follicular volume via laterally, rather than frontally, oriented flushing, leading to successful retrievals with no additional stress on the oocyte. A two-dimensional digital twin of the follicular environment is created and tested via multi-phase flow direct numerical simulation. Oocyte initial location within the follicle is varied, while quantities of interest such as velocity magnitude and vorticity are measured with a high level of precision. This provides insight into the overall fluid motion, as well as the trajectory and stresses experienced by the oocyte. A comparative benchmark set of tests indicated a higher success rate of the OxIVF needle of up to 100%, marking a significant improvement over the traditional double-lumen design whose success rate of no more than 75% was also highly dependent on the location of the needle tip inside the follicle. All forces measured during these tests showcase how the oocyte experiences stresses which are no larger than at the aspiration point, with the flow field providing a gentle steering effect towards the extraction region. Finally, the flow generation strategy maximises oocyte yield, unlocking new capabilities in both human and veterinary contexts.

Safe Service Delivery of a Complex Early Pregnancy Problem: Caesarean Scar Pregnancy.

Caesarean Scar Pregnancy (CSP) is an ectopic pregnancy with implantation into the niche of the uterine scar. We aimed to describe the local management of consecutive cases of CSP to develop a standard operating procedure (SOP). Between December 2019 and June 2022, there were 19,100 maternities. Of these, 23 were CSPs in 19 patients. Median BMI was 29 (range 20.5-52), median number of Caesarean deliveries (CS) was 2 (range 1-4) and 7/23 (30%) were cigarette smokers. At diagnosis, 9/23 were live pregnancies, 3/23 were retained products of conception (RPOC), 9/23 were pregnancies of uncertain viability (PUV), and 2/23 were non-viable. In six, the initial management was expectant, surgical suction evacuation with transrectal ultrasound guidance in 16, and one had a hysterectomy. The median blood loss was 100 mL (range 50-2000 mL). Two patients (9%) required a blood transfusion. Median hospital stay was 1 day (range 0-4). At follow-up after 10 weeks, no patients had an ongoing haematoma, and one had significant RPOC electing hysterectomy. Eight women were known to have 9 subsequent pregnancies (recurrent CSP n = 4, livebirth n = 2, miscarriage n = 2, tubal ectopic n = 1). Outcomes as rated by low blood loss, short hospital stay, and rare need for further intervention were favorable. Factors associated included prompt ultrasonographic diagnosis, availability of transrectal ultrasound guided surgery, and specialist follow-up, which form the basis of the SOP.

Is the clinician an independent variable in embryo transfer outcomes under standardized direct and indirect supervision? A 5-year observational cohort study.

Objective: To compare the cumulative pregnancy rate (CPR) for experienced clinicians and trainees naive to the skill of embryo transfer (ET) during an assisted reproductive treatment (ART) cycle. To establish the minimum number of procedures required to achieve consistent outcomes. Method: A non-interventional retrospective observational cohort study looking at all consecutive ETs undertaken over a 5-year study period. The CPR was determined by a self-reported urinary home pregnancy test undertaken 16 days after oocyte retrieval. Results: The CPR did not differ between an experienced clinician (39%) and trainee (45%) for the first 50 (p=0.41) and last 50 (40.7% versus 42.7%) (p=0.81) ET procedures. The CPR for the individuals remained consistent with their peaks and troughs mirroring the overall success rate of the unit. This pattern continued when the data was further stratified for co-variables (age [≤37 years of age], catheter type [soft] and embryo quality [expanded blastocyst of grade ≥2]): CPRs for experienced clinicians was 65.7% (first 50 transfers) and 40.9% (last 50 transfers); CPR for trainees was 66.7% (first 50 transfers) and 53.6% (last 50 transfers); p=0.95 and p=0.37, respectively. The trainees, however, were more likely to use a stylet catheter with a 2-step transfer technique, with a cost over clinical implication. Furthermore, patients expressed a preference for an experienced clinician to perform their procedure, despite being informed that the grade of the clinician had no impact on the cycle outcome after an analysis of the unit's data. Conclusion: The clinician's grade and duration of service have not been shown to significantly impact the outcome of the ART cycle. The findings, however, should be interpreted with caution, as they reflect the culture of training in the unit, where there is a strong emphasis on adequate direct and indirect supervision. Furthermore, the relationship between the volume of work and outcomes is established in postgraduate medical education, with the exact number required to achieve clinical competence being dependent on the procedure and intensity of the workload.

The correlation between raised body mass index and assisted reproductive treatment outcomes: a systematic review and meta-analysis of the evidence.

BACKGROUND: Public funding for fertility services within the United Kingdom is limited, and therefore, strict guidance exists regarding who can be offered treatment under the National Health Service (NHS). Body mass index (BMI) is a universal criteria adopted by both the public and private sector. This study addresses an important aspect of the impact of a raised BMI on fertility treatment outcomes. We standardise the analysis of the data by only including studies incorporating the WHO BMI criteria; the current reference point for clinicians and clinical commissioning groups in ascertaining which group of patients should receive treatment. This study is an update of the previous systematic review performed in 2010, with the inclusion of a larger number of cycles from central databases such as the Society for Assisted Reproductive Technology (SART). METHODS: An electronic literature search was conducted through the Cochrane, Medline and Embase libraries. Data extraction for each outcome measure was pooled and expressed as an odds ratio with 95% confidence intervals. Where clinical heterogeneity was evident, the random effects model was used to calculate the risk ratio and a fixed effects model was used for the remaining studies. A p value < 0.05 was considered statistically significant. RESULTS: A total of 49 studies have been identified and included in this systematic review. Overweight and obese (BMI ≥ 25 kg/m2) women have a statistically significant lower live birth rate (OR 0.81, 95% CI 0.74-0.89, p < 0.00001) following Assisted Reproductive Technology (ART) when comparisons are drawn to women with a normal BMI. An increase is also demonstrated in the number of miscarriages experienced by women with a BMI ≥ 30 kg/m2 (OR 1.52, 95% CI 1.28-1.81, p < 0.00001). CONCLUSION: Although this review concludes that a clear impact of BMI on ART outcomes is demonstrated, there remains questions as to the pathophysiology underlying these differences. This review supports the government's stringent criteria regarding BMI categories under which NHS funding is made available for ART, through a clear description of poor reproductive outcomes in women with a BMI ≥ 30 kg/m2.