Research question: How is assisted reproductive technology used by trans and/or non-binary (TNB) individuals and their partners at London Women's Clinic?
Design: This retrospective observational study examined treatments undertaken by TNB people at London Women's Clinic between 2011 and 2025. Demographic information on patients' age, body mass index, anti-Mullerian hormone, antral follicle count and history of gender-affirming hormone therapy/surgery was analysed. Outcomes included the types of treatment pursued, ongoing pregnancies, and live births.
Results: Sixty-four individuals who identified as TNB (n = 42) or had a TNB partner (n = 22) attended the clinic. Treatments included egg freezing (22 cycles), intrauterine insemination (IUI; 17 cycles) and IVF (25 cycles). A minority of IVF cycles involved intra-partner donation (reciprocal IVF; 2/25) or donor eggs (2/25). Three couples' journeys involved surrogacy arrangements. Most TNB individuals attended the clinic with a partner (n = 30), with the exception of those undertaking egg freezing. Of the individuals/couples attempting pregnancy (n =24), most (n =20) were using donor spermatozoa, with the exception of four couples (two involving transgender women who had frozen spermatozoa, and two involving cisgender men). Thirteen live births were achieved and four individuals were discharged from the clinic with ongoing pregnancies.
Conclusions: TNB individuals in the UK are successfully using the spectrum of assisted reproduction options, often with donor gametes and occasionally surrogacy, to build families. In this study, IVF out-performed IUI, underscoring that with inclusive, legally informed care pathways, family formation for TNB patients is both feasible and effective.
Research question: What is the incidence of endometrioma infections requiring surgical drainage following oocyte retrieval in women with ovarian endometrioma?
Design: This retrospective observational cohort study included women aged 18-43 years with a confirmed radiological diagnosis of ovarian endometrioma who underwent ovarian stimulation and oocyte retrieval for IVF/intracytoplasmic sperm injection (ICSI) or fertility preservation between January 2018 and December 2023 at a single tertiary academic centre. All procedures were performed under standardized aseptic conditions with antibiotic prophylaxis. Transcystic puncture was performed when deemed necessary. The primary outcome was the incidence of endometrioma infections requiring surgical drainage within 30 days after oocyte retrieval.
Results: Oocyte retrievals were performed in 1102 out of 1668 cycles (66.1%) for IVF/ICSI and in 566 cycles (33.9%) for fertility preservation. Bilateral endometriomas were present in 322 of 880 patients (36.6%), with a mean cyst (SD) diameter of 31.5 ± 22.7 mm. Endometriomas larger than 30 mm accounted for 295 of 649 cases (45.5%). Intentional transcystic puncture was performed in 76 of 1148 applicable procedures (6.6%), and endometrioma drainage during oocyte retrieval occurred in 52 cases (4.5%). Endometrioma infections requiring surgical drainage occurred in 6 of 1668 procedures (0.36%). Only one infection was reported following transcystic puncture (1.3%). No cases of sepsis or septic shock occurred. Five infections were managed with ultrasound-guided transvaginal drainage; one required laparoscopic surgery.
Conclusions: The incidence of endometrioma infection requiring surgical intervention after oocyte retrieval, including after transcystic puncture, is low. These findings support the safety of assisted reproductive techniques in women with endometriomas.
Micro- and nanoplastics (MNP) are pervasive pollutants, detected in every ecosystem. Human exposure is extensive, and their capacity to cross biological barriers and accumulate in tissues raises growing concerns about reproductive health and pregnancy outcomes. Research has shown the presence of MNP in human placenta, fetal meconium and amniotic fluid, confirming their ability to reach the fetal compartment, potentially increasing risks for fetal development. In women, MNP have also been detected in follicular fluid, although their specific effects remain to be determined. In-vitro studies have reported MNP-induced placental vascular damage, whereas murine models suggest impaired ovarian function, reduced oocyte quality and decreased pregnancy rates after MNP exposure. In men, MNP have been identified in testicular tissue and semen. Animal studies report decreased sperm count and quality, likely because of oxidative stress, hormonal disruption and inflammation. Various techniques are available for detecting MNP in biological tissues. Mass and Raman spectroscopy are among the most widely used, each offering specific advantages and limitations. Interpreting experimental data also requires caution, as many in-vitro and in-vivo models use unrealistically high doses of pristine polymers lacking environmental additives, potentially limiting the relevance of their findings to real-world exposures.
Research question: Are endocrine-disrupting chemicals (EDC) in follicular fluid associated with assisted reproductive technology (ART) outcomes among women undergoing ART treatment?
Design: This prospective cohort study involved 176 women who underwent ART treatment in China. The concentrations of 76 EDC, across five categories, in follicular fluid were quantified. Generalized linear models (with and without restricted cubic splines to account for non-linear relationships) and Bayesian kernel machine regression (BKMR) models were utilized.
Results: Fifteen EDC exhibited significant negative associations with at least one conventional IVF/intracytoplasmic sperm injection (ICSI) outcome. Notably, mono (2-ethyl-5-carboxypentyl) phthalate (MECPP) was consistently associated with reductions in all conventional IVF/ICSI outcomes, including the numbers of retrieved oocytes, mature oocytes, two pronuclear zygotes, blastocysts and high-quality embryos. Similarly, 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHT-COOH) was negatively associated with all conventional IVF/ICSI outcomes except the number of blastocysts. No significant negative associations were observed between individual EDC and pregnancy outcomes, including the live birth rate. BKMR model analyses revealed that combinations of EDC were significantly associated with reductions in the numbers of retrieved oocytes and mature oocytes, and the probability of biochemical pregnancy. Among EDC combinations, phthalates (PAE) and bisphenol S (BPS) were identified as dominant contributors to adverse conventional IVF/ICSI outcomes and the biochemical pregnancy rate, respectively. Stratified and interaction analyses further indicated that stronger associations with conventional IVF/ICSI outcomes were observed among women aged ≤33 years.
Conclusions: Elevated concentrations of EDC in follicular fluid were associated with adverse ART outcomes, both as individual compounds and in combination. MECPP, BHT-COOH, PAE and BPS were identified as key EDC. Moreover, the associations were modified by age, with stronger adverse effects observed in younger women.
Research question: Does the synergistic interaction between blastocyst-stage embryo transfer and vitrification in assisted reproductive technology increase the risk of adverse neonatal outcomes, specifically elevated birth weight z-scores and a higher incidence of clinically concerning large for gestational age (LGA) or macrosomia in offspring?
Design: In this cohort study, multivariable regression analyses were conducted to examine the association between embryo transfer strategies (fresh versus frozen; cleavage versus blastocyst stage) and the birth weight z-score of singletons, as well as the incidence of LGA and macrosomia among 42,190 singleton live births from the Center for Reproductive Medicine at Peking University Third Hospital between 2012 and 2022.
Results: Compared with cleavage-stage embryo transfer, newborns resulting from blastocyst-stage transfers had significantly higher birth weight z-scores (P < 0.001), LGA (P < 0.001) and macrosomia (P = 0.013). Frozen embryo transfer (only vitrified-warmed) was associated with increased birth weight z-scores (P = 0.001), LGA (P = 0.004) and macrosomia (P = 0.007), compared with fresh embryo transfers. A significant synergetic effect of blastocyst transfer and vitrified-warmed transfer concerning the LGA was found (relative excess risks due to interaction = 0.24; 95% CI 0.06 to 0.42; P = 0.022 for multiplicative interaction term) on the additive and multiplicative scales.
Conclusions: Blastocyst stage and embryo vitrification were associated with elevated birth weight z-scores and an increased likelihood of LGA, with evidence of a synergistic effect. These findings support the importance of personalized clinical decision-making in the use of vitrified-warmed cleavage-stage transfer, particularly in the absence of clear medical indications.

