J M Jenkins

University of Bristol, Bristol, England, United Kingdom

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Publications (32)104.38 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. · 2.68 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. · 4.67 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. · 4.67 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. · 4.67 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. · 4.67 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. · 4.67 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. · 3.76 Impact Factor
  • R S Mathur, J M Jenkins
    BJOG An International Journal of Obstetrics & Gynaecology 09/2000; 107(8):943-6. · 3.76 Impact Factor
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    ABSTRACT: OBJECTIVE: To compare patient and cycle characteristics among three study groups: early ovarian hyperstimulation syndrome (OHSS), late OHSS, and non-OHSS. DESIGN: Prospective observational study.Setting: University assisted conception service. PATIENT(s): Women undergoing in vitro fertilization, intracytoplasmic sperm injection or gamete intrafallopian transfer treatment at Bristol University In Vitro Fertilization Service between January 1, 1995, and December 31, 1998. INTERVENTION: None. MAIN OUTCOME MEASURE(s): Patient age, prevalence of polycystic ovaries, gonadotropin requirement, peak serum estradiol (E(2)) concentration, number of oocytes retrieved, clinical pregnancy rate, number of gestation sacs, and severity of OHSS. RESULT(s): Women with early OHSS had significantly higher serum E(2) levels and lower gonadotropin requirements than did the other groups. Cycles with either early or late OHSS had significantly more oocytes collected than those without OHSS. Serum E(2) and oocyte numbers did not accurately predict the risk of developing late OHSS. Clinical pregnancies occurred in all cycles with late OHSS, and multiple pregnancies were significantly more frequent in the late OHSS group than in the other groups. Late OHSS was more likely than early OHSS to be severe. CONCLUSION(s): Early OHSS relates to "excessive" preovulatory response to stimulation, whereas late OHSS depends on the occurrence of pregnancy, is likelier to be severe, and is only poorly related to preovulatory events.
    Fertility and Sterility 06/2000; 73(5):901-7. · 4.17 Impact Factor
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    ABSTRACT: To further elucidate cortisol metabolism in the follicular microenvironment at the time of oocyte retrieval, the presence of 11beta-hydroxysteroid dehydrogenase (HSD) messenger (m)RNA transcripts in oocytes; cumulus cells; granulosa cells; and CD45(+), CD15(+) leukocytes was assessed semiquantitatively. Controlled study using semiquantitative assessment of 11beta-HSD mRNA. University IVF center. Twenty-six patients undergoing controlled ovarian hyperstimulation for assisted conception. Metaphase II oocytes; cumulus cells; granulosa cells, and CD45(+), CD15(+) leukocytes from individual follicular fluid aspirates. Semiquantitative analysis of PCR products after total RNA extraction and complementary DNA synthesis. Periovulatory human oocytes; cumulus cells; CD45(+), CD15(+) leukocytes; and granulosa cells consistently express type 1 but not type 2 11beta-HSD mRNA. Expression of mRNA is greatest in cumulus cells. Type 1 11beta-HSD mRNA expression varies considerably in all cell types and among individual follicles and patients. These studies of mRNA expression suggest that the enzymes present both in and around the periovulatory oocyte will favor a high-cortisol environment.
    Fertility and Sterility 05/2000; 73(4):825-30. · 4.17 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. · 4.67 Impact Factor
  • R S Mathur, J M Jenkins
    Human Reproduction 10/1999; 14(9):2183-5. · 4.67 Impact Factor
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    ABSTRACT: To determine whether a relation exists between previous exposure to Chlamydia trachomatis and impaired ovarian response to gonadotropin stimulation. Controlled clinical study. Two university IVF centers. Two hundred forty-two patients receiving IVF treatment and 81 control patients. Ninety-four patients with a poor response to IVF, defined by cycle cancellation in response to a daily stimulation dose of 300 IU of FSH, and 148 patients with a good response were matched for age. Twenty-eight pregnant controls and 53 controls of proven fertility also were included. Serum samples were obtained from patients and controls. Serum levels of immunoglobulin (Ig) G antibodies to C. trachomatis were determined by ELISA. The prevalence of serum IgG antibodies to C. trachomatis in critically defined poor responders was compared with that of age-matched good responders. A significantly higher proportion of poor responders had serum IgG antibodies to C. trachomatis compared with good responders (44.7% and 30.4%, respectively). Patients undergoing IVF had a significantly higher prevalence of IgG antibodies to C. trachomatis (36%) than did either pregnant or nonpregnant controls (12%). A significantly higher prevalence of serum IgG antibodies to C. trachomatis was observed in critically defined poor responders, suggesting a possible detrimental effect of C. trachomatis on subsequent ovarian function.
    Fertility and Sterility 09/1998; 70(2):214-8. · 4.17 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.
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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. · 4.67 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. · 4.54 Impact Factor
  • C R Harlow, J M Jenkins, R M Winston
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    ABSTRACT: To determine the changes in follicular fluid (FF) total and free cortisol during the LH surge in naturally ovulating women. Twenty-six women having diagnostic laparoscopy during the follicular phase of normal menstrual cycles were selected. Blood samples were collected 1 day before, the day of, and 1 day after surgery and the results of serum E2 and LH were used to divide the cycles retrospectively into pre- and post-LH surge groups. Follicular fluid was collected during laparoscopy. Serum P, total and free cortisol, and FF volume, E2, P, total cortisol, and free cortisol were measured on the day of surgery. Median serum and FF P levels were significantly higher in the post-LH surge group compared with the pre-LH surge group (0.54 versus 1.54 ng/mL [1.7 versus 4.85 nmol/L] and 5.03 versus 28.0 micrograms/mL [15.8 versus 88.0 mumol/L], respectively). Follicular fluid volume also increased significantly after the surge (2.5 versus 4.5 mL). Median serum total and free and percent free cortisol were higher after the surge, although not significantly. In contrast, FF total, free, and percent free levels increased dramatically between pre- and post-LH surge samples (4.41 versus 43.6 ng/mL [16.0 versus 158 nmol/L], 0.138 versus 6.68 ng/mL [0.5 versus 24.2 nmol/L], and 3.3% versus 15.0%, respectively; P < 0.05). An increase in total and free cortisol occurs in the follicle during the LH surge. Cortisol and its regulation by 11 beta-hydroxysteroid dehydrogenase therefore may exert a physiologic role in oocyte maturation or ovulation.
    Fertility and Sterility 08/1997; 68(1):48-53. · 4.17 Impact Factor
  • British Journal of Obstetrics and Gynaecology 06/1997; 104(5):521-7.
  • A V Akande, R S Mathur, S D Keay, J M Jenkins
    British Journal of Obstetrics and Gynaecology 11/1996; 103(10):963-6.
  • British Journal of Obstetrics and Gynaecology 09/1996; 103(8):740-6.

Publication Stats

616 Citations
104.38 Total Impact Points


  • 1995–2006
    • University of Bristol
      Bristol, England, United Kingdom
  • 2001–2003
    • The University of Warwick
      • Biological Sciences
      Warwick, ENG, United Kingdom
  • 1995–1999
    • Saint Michael's Medical Center
      Newark, New Jersey, United States
  • 1992–1995
    • The University of Sheffield
      Sheffield, England, United Kingdom
  • 1991–1994
    • University of Southampton
      Southampton, England, United Kingdom