J M Jenkins

University of Bristol, Bristol, England, United Kingdom

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Publications (23)64.33 Total impact

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    ABSTRACT: The objective of this study was to investigate whether a change in assisted hatching (AH) technique from total to partial penetration of the zona pellucida improved the outcome of IVF and intracytoplasmic sperm injection cycles where AH was indicated. This was an observational study conducted from the beginning of January 2000 to the end of April 2005. Total AH was performed in 312 cycles, while partial AH was performed in 592 cycles. In women of all ages, implantation, clinical pregnancy and live birth rates were higher in the partial AH group than in the total AH group (12.6 versus 7.2%, P = 0.0001; 22.3 versus 15.7%, P = 0.02; 18.2 versus 12.5%, P = 0.03 respectively). The benefit of partial AH was most marked in women under 38 years old (i.e. the recurrent implantation failure group). The authors conclude that partial AH is associated with higher implantation and pregnancy rates than total AH, especially in women under 38 years old who suffer from recurrent implantation failure.
    Reproductive biomedicine online 09/2006; 13(2):261-7. DOI:10.1016/S1472-6483(10)60624-4 · 2.98 Impact Factor
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    ABSTRACT: Follicular aspirates represent a snapshot in time of conditions within the follicle at oocyte retrieval in women undergoing in vitro fertilization and embryo transfer. This clinical material has been much investigated and yet its cellular composition remains unclear. In this study we investigated the origin and profile of leukocytes found within follicular aspirates. We performed morphological and immunohistochemical analyses of follicular aspirates and peripheral blood obtained concurrently at oocyte retrieval. There was no correlation between erythrocyte and leukocyte numbers in follicular aspirates. The profile of leukocyte subtypes within follicular aspirates was variable and differed significantly from the peripheral circulation in a significant proportion of the analysed samples. A subset of follicular aspirates displayed a marked increase in monocytes/macrophages and an apparent concomitant reduction in polymorphonuclear leukocytes compared with peripheral blood. Leukocytes within follicular aspirates cannot be accounted for solely as a result of blood vessel damage during oocyte retrieval. The variation in leukocyte subtypes observed in some follicular aspirates may reflect a coordinated infiltration of these cells, characteristic of progressive inflammatory responses in other systems. The possibility that leukocyte variation is indicative of follicular maturation deserves further investigation due to its potential relevance in optimizing oocyte selection.
    Human Reproduction 01/2006; 20(12):3526-31. DOI:10.1093/humrep/dei240 · 4.59 Impact Factor
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    ABSTRACT: Poor ovarian response limits IVF success but assessing interventions is difficult because of the wide variation in definition. This study attempts to derive objective definitions of poor response. A retrospective study of a consecutive series of 1190 patients aged <40 years undergoing their first IVF/ICSI cycle was undertaken. Factors adversely affecting implantation, including advanced female age, were excluded. Clinical outcome in cycles reaching oocyte retrieval (n = 1036) were evaluated with respect to gonadotrophin dose used and oocyte number. Cancelled cycles (n = 154) were analysed in relation to the stimulation dose at cancellation and outcome of their subsequent cycle. Cycle cancellation for patients on >/=300 IU FSH/day compared to those on a lower dose was associated with a significantly worse outcome in the subsequent cycle. If <3000 IU FSH/cycle were administered, clinical pregnancy rates remained favourable if <4 eggs were recovered (29 versus 33% for >/=5 eggs). By contrast, if >/=3000 IU FSH was required, the pregnancy rate was 25% if >/=5 eggs were recovered but declined to 7% if <4 were obtained. Definitions of poor response should include the degree of ovarian stimulation used. A low oocyte number is only detrimental if the cumulative dose is >3000 IU FSH. Cancellation at >/=300 IU FSH/day is associated with a significantly worse prognosis and could define poor response.
    Human Reproduction 08/2004; 19(7):1544-7. DOI:10.1093/humrep/deh273 · 4.59 Impact Factor
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    ABSTRACT: Insulin-like growth factor-1 (IGF-1) is known to play a role in ovarian follicular development augmenting the action of FSH. Low intrafollicular concentrations have been detected in women who respond poorly to gonadotrophins. This study addresses the relationship between serum IGF-1 levels following pituitary desensitization and ovarian response to gonadotrophin stimulation. This is a case-control study of 78 patients undergoing IVF-embryo transfer treatment. Thirty-nine strictly-defined poor responder patients requiring 50 or more ampoules (75 IU FSH) to reach oocyte retrieval were compared with 39 age-matched normal responders, requiring fewer than 50 ampoules. IGF-1 concentrations were determined by extraction radioimmunoassay on serum samples obtained after pituitary desensitization but prior to gonadotrophin stimulation. Despite highly significant differences in measures of ovarian response between groups, the mean serum IGF-1 concentration was not statistically significantly different between poor and normal responders [(31.5 nmol/l [95% confidence interval (CI) 28.5-34.5] versus 34.5 nmol/l (95% CI 31.8-37.2)] respectively. No correlation between oocyte number or total gonadotrophin used and serum IGF-1 concentration was observed. Whilst IGF-1 influences ovarian follicular development this study suggests that serum IGF-1 does not predict ovarian response and does not differentiate between critically-defined poor and normal responders.
    Human Reproduction 10/2003; 18(9):1797-801. DOI:10.1093/humrep/deg386 · 4.59 Impact Factor
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    ABSTRACT: The present study addresses the issue of biological ageing of the oocyte (as indicated by basal serum FSH levels) versus chronological ageing. 1019 infertile but ovulating women were studied in their first cycle of IVF treatment. A series of logistic regression models were developed to assess statistical significance of effects of age and FSH on implantation rates and live babies born. The number of oocytes retrieved and embryos available for transfer declined with increasing age and basal serum FSH concentrations. Fertilizing ability of oocytes increased with advancing age but was not affected by FSH concentrations. Although the number of oocytes or embryos available for transfer had no independent effect on implantation rates, the implanting ability of fertilized oocytes (embryos) was inversely related to increasing age and independently to FSH. The chance of a baby being born, however, was determined more by age than by serum FSH. Ovarian ageing affecting oocyte quality and fecundity can occur independently of chronological age. This has important practical implications whereby serum basal FSH measurement may be a valuable prognostic index, though chronological age remains important.
    Human Reproduction 09/2002; 17(8):2003-8. · 4.59 Impact Factor
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    ABSTRACT: Conception following gonadotrophin-stimulated IVF and embryo transfer has been associated with a higher intrafollicular cortisol:cortisone ratio and decreased metabolism of cortisol to cortisone. The role of glucocorticoids in human oocyte maturation is not fully understood, but active glucocorticoid (cortisol) may be important. This study relates intrafollicular cortisol and cortisone concentrations to oocyte fertilization and embryo implantation in unstimulated cycles. Patients aged <40 years with favourable sperm underwent unstimulated IVF-embryo transfer. Study 1 related intrafollicular cortisol levels to oocyte and IVF outcome: (i) fertilized, pregnant (n = 9); (ii) fertilized, not pregnant (n = 21); and (iii) unfertilized (n = 12). Study 2 was a case-control study of 27 patients (same outcome groups of equal size) which measured intrafollicular cortisol, cortisone and the cortisol:cortisone ratio. Conception cycles demonstrated higher cortisol concentrations compared with the fertilized group (study 1) [median (95% confidence interval): 299 (249-330) versus 227 nmol/l (185-261); P < 0.05] and higher cortisol:cortisone ratios when compared with the unfertilized group (study 2) [7.38 (5.23-9.19) versus 3.56 (1.75-7.46) respectively; P = 0.02]. Of the women with cortisol:cortisone ratios greater than the outcome independent mean of 5.90, 58% conceived compared with only 13% with ratios <5.90 (P < 0.02). Higher cortisol:cortisone ratios in conception cycles suggest that active glucocorticoid may be important for final oocyte maturation and embryo implantation in unstimulated cycles.
    Human Reproduction 09/2002; 17(9):2410-4. DOI:10.1093/humrep/17.9.2410 · 4.59 Impact Factor
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    ABSTRACT: Cancellation of assisted conception cycles because of poor ovarian response to gonadotrophins is a significant problem in assisted reproduction. Various adjuvant treatments have been suggested to improve responsiveness. This study reports on the potential benefits of low dose dexamethasone. Patients <40 years of age were invited to participate in a twin centre prospective double blind randomized placebo controlled study. A total of 290 patients were recruited and computer randomized using sealed envelopes to receive either 1 mg dexamethasone (n = 145) or placebo tablets (n = 145) in addition to a standard long protocol gonadotrophin-releasing hormone analogue with gonadotrophin stimulation regime. A significantly lower cancellation rate for poor ovarian response was observed in the dexamethasone group compared with controls (2.8 versus 12.4% respectively, P < 0.002). Further comparisons between the dexamethasone group and controls were made of median fertilization rates (60 versus 61% respectively, NS), implantation rates (16.3 versus 11.6% respectively, NS) and pregnancy rate per cycle started (26.9 versus 17.2%, NS). The benefit was apparent in patients both with polycystic and normal ovaries. Low dose dexamethasone co-treatment reduces the incidence of poor ovarian response. It may increase clinical pregnancy rates and should be considered for inclusion in stimulation regimes to optimize ovarian response.
    Human Reproduction 10/2001; 16(9):1861-5. · 4.59 Impact Factor
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    ABSTRACT: Following a detailed information technology survey in the South West Deanery, an Internet educational programme in reproductive medicine was constructed, delivered and assessed. The course followed a problem-based approach using case studies, using an education website and electronic mail (e-mail) to communicate between trainees and trainers. Independent evaluation revealed a high level of satisfaction for both trainees and trainers with an increase in trainees' confidence to deal with patients following the course. This study suggests that the Internet may be used effectively to deliver postgraduate medical education, if the training programme is designed appropriately to computer infrastructure and the computer literacy of the users.
    BJOG An International Journal of Obstetrics & Gynaecology 02/2001; 108(1):114-6. DOI:10.1111/j.1471-0528.2001.00010.x · 3.86 Impact Factor
  • R S Mathur, J M Jenkins
    BJOG An International Journal of Obstetrics & Gynaecology 09/2000; 107(8):943-6. DOI:10.1111/j.1471-0528.2000.tb10393.x · 3.86 Impact Factor
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    ABSTRACT: There is growing evidence that the pathogenic effects of bacterial vaginosis may not be confined to the lower genital tract. Possible associations with infertility and effects on fertilization and implantation were studied in patients undergoing in-vitro fertilization (IVF) treatment. High vaginal swabs taken at the time of oocyte collection were assessed by Gram staining. The prevalence of bacterial vaginosis and of intermediate and normal flora in 301 patients was 25.6, 14.0 and 60.4% respectively. Bacterial vaginosis was more prevalent in patients with tubal (31.5%, n = 149) compared with non-tubal (19.7%, n = 152) infertility (odds ratio (OR) 1.87, CI 1.11-3.18, P = 0.02). Bacterial vaginosis did not have an adverse effect on fertilization rate. Further, no significant difference in implantation rates was seen when comparing bacterial vaginosis (15. 8%, OR 1.03, CI 0.66-1.61) and intermediate flora (13.1%, OR 0.82, CI 0.45-1.52) with normal flora (15.5%). Though confidence intervals around the observations were relatively wide, the findings suggest that routine screening for bacterial vaginosis in the hope of improving the success of IVF treatment is not justified. The prevention of complications in pregnancy associated with bacterial vaginosis might be a more relevant indication for screening at the time of IVF treatment, in particular patients with tubal disease, if treatment were shown to be effective for that particular purpose. However, antibiotic treatment before IVF has been shown to be positively disadvantageous for IVF by encouraging other organisms.
    Human Reproduction 10/1999; 14(9):2411-5. · 4.59 Impact Factor
  • R S Mathur, J M Jenkins
    Human Reproduction 10/1999; 14(9):2183-5. · 4.59 Impact Factor
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    S D Keay, N H Liversedge, J M Jenkins
    British Journal of Obstetrics and Gynaecology 03/1998; 105(3):252-3. DOI:10.1111/j.1471-0528.1998.tb10082.x
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    R S Mathur, J M Jenkins, A S Bansal
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    ABSTRACT: This review examines recent evidence suggesting a role for the immune system, in particular cytokines, in the pathogenesis of ovarian hyperstimulation syndrome (OHSS). Ovarian tissue is known to contain cells capable of producing a range of immunological mediators and the concentrations of these have been shown to be elevated in serum and ascitic fluid from women with established OHSS. Available evidence points to a role for vascular endothelial growth factor and interleukin-2, possibly acting through other intermediary cytokines, in the pathogenesis of OHSS. However, each individual has a unique cytokine profile and several cytokines may share biological actions, making it difficult to interpret data on isolated cytokine concentrations from relatively small numbers of patients. Improved understanding of the role of the immune system in the development of OHSS may have implications for the prediction, prevention and management of this iatrogenic condition.
    Human Reproduction 01/1998; 12(12):2629-34. DOI:10.1093/humrep/12.12.2629 · 4.59 Impact Factor
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    ABSTRACT: The activity of 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) in human granulosa cells has been shown to be associated with the outcome of treatment following in-vitro fertilization and embryo transfer. There are two known isoforms of 11 beta-HSD which differ significantly in their actions and co-factor requirements. The net activity of 11 beta-HSD which differ significantly in their actions and co-factor requirements. The net activity of 11 beta-HSD within the human ovary is unclear, but may be of particular importance within the ovarian follicle in regulating possible glucocorticoid influences on the oocyte. This study presents preliminary information regarding establishment of techniques to identify transcripts of the 11 beta-HSD isoforms within human granulosa cells and human cumulus cells using reverse transcription-polymerase chain reaction. In view of the high expression of the type 1 11 beta-HSD isoform and the possibility of other 11 beta-HSD isoforms in the ovary, plasmid technology was used to confirm the technique specifically identifying the known isoforms.
    Molecular Human Reproduction 09/1997; 3(8):651-4. · 3.48 Impact Factor
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    British Journal of Obstetrics and Gynaecology 06/1997; 104(5):521-7. DOI:10.1111/j.1471-0528.1997.tb11525.x
  • AV Akande, R S Mathur, S D Keay, J M Jenkins
    British Journal of Obstetrics and Gynaecology 11/1996; 103(10):963-6. DOI:10.1111/j.1471-0528.1996.tb09543.x
  • R S Mathur, LA Joels, AV Akande, J M Jenkins
    British Journal of Obstetrics and Gynaecology 09/1996; 103(8):740-6. DOI:10.1111/j.1471-0528.1996.tb09867.x
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    ABSTRACT: We questioned the policy of routine microbiological culture of semen prior to in-vitro fertilization (IVF) with a view to prescribing antibiotics to reduce the risk of introducing seminal infection into the embryo culture system. An initial retrospective study examined serum microbiology reports of 449 couples undergoing IVF or gamete intra-Fallopian transfer (GIFT). In semen samples taking >/=1 days to reach the microbiology laboratory compared with same-day delivery there was increased frequency of significant culture of enterococci (27 versus 15%, P < 0.01). In samples taking >/=2 days there was increased frequency of significant culture of Gram-negative bacilli (31 versus 12%, P < 0.01) and of overall culture of other potentially pathogenic organisms (26 versus 14%, P < 0.01). We questioned diagnostic accuracy and relevance. Therefore, in a prospective study, semen and high vaginal swabs obtained on the day of oocyte collection were cultured from 100 couples having IVF or GIFT, of whom 52 male partners had been treated with antibiotics following positive pre-IVF semen culture. The presence of bacteria in semen samples used only for IVF (n = 90) did not reduce fertilization rates nor lead to infection of the embryo culture system. However, there was an increased incidence of significant culture of vaginal Gram-negative bacilli in patients with treated partners compared with untreated partners [15/52 (29%) versus 5/48 (10%), P < 0.05]. Thus antibiotic therapy in the male partner may increase the likelihood of inoculation of antibiotic-resistant pathogenic bacteria from the vagina into the embryo culture system during vaginal oocyte collection. In asymptomatic patients, microbiological screening of semen samples prior to IVF treatment and subsequent treatment with antibiotic therapy in those with positive cultures appears to be unnecessary and may be detrimental to IVF outcome.
    Human Reproduction 06/1996; 11(6):1227-31. DOI:10.1093/oxfordjournals.humrep.a019361 · 4.59 Impact Factor
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    J M Jenkins, R S Mathur
    British Journal of Obstetrics and Gynaecology 12/1995; 102(11):935. DOI:10.1111/j.1471-0528.1995.tb10888.x
  • J M Jenkins, P F Brook, S Sargeant, I D Cooke
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    ABSTRACT: To determine whether an inter-relationship exists between endocervical mucus pH, serum androgen levels, and waist to hip (W:H) ratio. Donor insemination clinic, University of Sheffield, Jessop Hospital, Sheffield, United Kingdom. One hundred patients receiving donor insemination. Waist, hip, height, and weight measurements were recorded for 100 patients receiving donor insemination. At the onset of the LH surge when patients attended for their first insemination, a sample of endocervical mucus and blood was taken. The Insler score of the mucus was recorded and the pH was measured with multirange pH paper. Of the 100 patients studied, 10 cases had an endocervical mucus pH < 6 despite Insler scores of > 10. Serum T, DHEAS, and androstenedione levels were measured in the 10 patients with pH < 6 and in 26 patients selected at random from the 90 patients with pH > or = 6. The W:H ratio was significantly higher in the patients with pH < 6 than pH > or = 6. No significant difference was seen in body mass index between the latter groups. All serum androgen levels were significantly higher in the patients with pH < 6 than pH > or = 7. A potential link (serum androgen levels) between a powerful predictive factor of fertility (W:H ratio) and a potential mechanism of subfertility (low endocervical mucus pH) has been demonstrated. This observation warrants further detailed evaluation particularly as it has been shown that a low endocervical mucus pH may be corrected by simple inexpensive treatment.
    Fertility and Sterility 05/1995; 63(5):1005-8. · 4.30 Impact Factor

Publication Stats

572 Citations
64.33 Total Impact Points

Institutions

  • 1995–2006
    • University of Bristol
      Bristol, England, United Kingdom
    • The University of Sheffield
      Sheffield, England, United Kingdom
  • 1995–1999
    • Saint Michael's Medical Center
      Newark, New Jersey, United States