Human female meiosis revised: new insights into the mechanisms of chromosome segregation and aneuploidies from advanced genomics and time-lapse imaging
ABSTRACTBACKGROUNDThe unbalanced transmission of chromosomes in human gametes and early preimplantation embryos causes aneuploidy, which is a major cause of infertility and pregnancy failure. A baseline of 20% of human oocytes are estimated to be aneuploid and this increases exponentially from 30 to 35 years, reaching on average 80% by 42 years. As a result, reproductive senescence in human females is predominantly determined by the accelerated decline in genetic quality of oocytes from 30 years of age.OBJECTIVE AND RATIONALEUnderstanding mechanisms of chromosome segregation and aneuploidies in the female germline is a cru...
Source: Human Reproduction Update - August 30, 2017 Category: OBGYN Source Type: research
Disentangling puberty: novel neuroendocrine pathways and mechanisms for the control of mammalian puberty
AbstractBACKGROUNDPuberty is a complex developmental event, controlled by sophisticated regulatory networks that integrate peripheral and internal cues and impinge at the brain centers driving the reproductive axis. The tempo of puberty is genetically determined but is also sensitive to numerous modifiers, from metabolic and sex steroid signals to environmental factors. Recent epidemiological evidence suggests that the onset of puberty is advancing in humans, through as yet unknown mechanisms. In fact, while much knowledge has been gleaned recently on the mechanisms responsible for the control of mammalian puberty, fundame...
Source: Human Reproduction Update - August 30, 2017 Category: OBGYN Source Type: research
Human female meiosis revised: new insights into the mechanisms of chromosome segregation and aneuploidies from advanced genomics and time-lapse imaging
ABSTRACTBACKGROUNDThe unbalanced transmission of chromosomes in human gametes and early preimplantation embryos causes aneuploidy, which is a major cause of infertility and pregnancy failure. A baseline of 20% of human oocytes are estimated to be aneuploid and this increases exponentially from 30 to 35 years, reaching on average 80% by 42 years. As a result, reproductive senescence in human females is predominantly determined by the accelerated decline in genetic quality of oocytes from 30 years of age.OBJECTIVE AND RATIONALEUnderstanding mechanisms of chromosome segregation and aneuploidies in the female germline is a cru...
Source: Human Reproduction Update - August 30, 2017 Category: OBGYN Source Type: research
Zika virus and reproduction: facts, questions and current management
AbstractBACKGROUNDZika virus (ZIKV) is an arthropod-borne virus of the family Flaviviridae, genus Flavivirus. ZIKV is currently the focus of an ongoing pandemic and worldwide public health emergency. Although originally isolated in 1947, its pathogenesis was poorly known and very few documented infections were published until recently. Its route of transmission and its impact on reproduction and pregnancy have only recently begun to be disclosed.OBJECTIVE AND RATIONALEThis review summarizes the most recent knowledge about ZIKV infection and pathogenesis and focuses on its impacts on male and female genital tracts, includin...
Source: Human Reproduction Update - August 9, 2017 Category: OBGYN Source Type: research
Metabolomics as a tool to identify biomarkers to predict and improve outcomes in reproductive medicine: a systematic review
AbstractBACKGROUNDInfertility is a complex disorder with significant medical, psychological and financial consequences for patients. With live-birth rates per cycle below 30% and a drive from the Human Fertilisation and Embryology Authority (HFEA) to encourage single embryo transfer, there is significant research in different areas aiming to improve success rates of fertility treatments. One such area is investigating the causes of infertility at a molecular level, and metabolomics techniques provide a platform for studying relevant biofluids in the reproductive tract.OBJECTIVE AND RATIONALEThe aim of this systematic revie...
Source: Human Reproduction Update - August 8, 2017 Category: OBGYN Source Type: research
Temporal trends in sperm count: a systematic review and meta-regression analysis
AbstractBACKGROUNDReported declines in sperm counts remain controversial today and recent trends are unknown. A definitive meta-analysis is critical given the predictive value of sperm count for fertility, morbidity and mortality.OBJECTIVE AND RATIONALETo provide a systematic review and meta-regression analysis of recent trends in sperm counts as measured by sperm concentration (SC) and total sperm count (TSC), and their modification by fertility and geographic group.SEARCH METHODSPubMed/MEDLINE and EMBASE were searched for English language studies of human SC published in 1981 –2013. Following a predefined protocol 7518...
Source: Human Reproduction Update - July 25, 2017 Category: OBGYN Source Type: research
The diagnosis of male infertility: an analysis of the evidence to support the development of global WHO guidance —challenges and future research opportunities
AbstractBACKGROUNDHerein, we describe the consensus guideline methodology, summarize the evidence-based recommendations we provided to the World Health Organization (WHO) for their consideration in the development of global guidance and present a narrative review of the diagnosis of male infertility as related to the eight prioritized (problem or population (P), intervention (I), comparison (C) and outcome(s) (O) (PICO)) questions. Additionally, we discuss the challenges and research gaps identified during the synthesis of this evidence.OBJECTIVE AND RATIONALEThe aim of this paper is to present an evidence-based approach f...
Source: Human Reproduction Update - July 19, 2017 Category: OBGYN Source Type: research
Nitric oxide-heat shock protein axis in menopausal hot flushes: neglected metabolic issues of chronic inflammatory diseases associated with deranged heat shock response
AbstractBACKGROUNDAlthough some unequivocal underlying mechanisms of menopausal hot flushes have been demonstrated in animal models, the paucity of similar approaches in humans impedes further mechanistic outcomes. Human studies might show some as yet unexpected physiological mechanisms of metabolic adaptation that permeate the phase of decreased oestrogen levels in both symptomatic and asymptomatic women. This is particularly relevant because both the severity and time span of hot flushes are associated with increased risk of chronic inflammatory disease. On the other hand, oestrogen induces the expression of heat shock p...
Source: Human Reproduction Update - July 18, 2017 Category: OBGYN Source Type: research
Baseline anatomical assessment of the uterus and ovaries in infertile women: a systematic review of the evidence on which assessment methods are the safest and most effective in terms of improving fertility outcomes
Discussion of the data, and resultant consensus for best practice were accomplished in a consensus expert consultation in Geneva, October 2015. An independent expert review process concerning this work and outcomes was conducted during 2016.OUTCOMESThe draft recommendations presented here apply to infertile women whether or not they are undergoing fertility treatment. Transvaginal ultrasound (TVUS) should be offered to all infertile women with symptoms or signs of anatomic pelvic pathology. TVUS should not be offered routinely to women without symptoms of pelvic pathology. Hysteroscopy should be offered if intrauterine pat...
Source: Human Reproduction Update - July 18, 2017 Category: OBGYN Source Type: research
GnRH antagonist versus long agonist protocols in IVF: a systematic review and meta-analysis accounting for patient type
AbstractBACKGROUNDMost reviews of IVF ovarian stimulation protocols have insufficiently accounted for various patient populations, such as ovulatory women, women with polycystic ovary syndrome (PCOS) or women with poor ovarian response, and have included studies in which the agonist or antagonist was not the only variable between the compared study arms.OBJECTIVE AND RATIONALEThe aim of the current study was to compare GnRH antagonist protocols versus standard long agonist protocols in couples undergoing IVF or ICSI, while accounting for various patient populations and treatment schedules.SEARCH METHODSThe Cochrane Menstru...
Source: Human Reproduction Update - July 14, 2017 Category: OBGYN Source Type: research
The role of TGF- β in the pathophysiology of peritoneal endometriosis
AbstractBACKGROUNDEndometriosis is estimated to affect 6 –10% of women of reproductive age and it is associated with chronic pelvic pain, dysmenorrhoea and subfertility. It is currently managed surgically or medically but symptoms recur in up to 75% of cases and available medical treatments have undesirable side effects. Endometriosis is defined as the presence of endometrial tissue outside the uterus with lesions typically found on the peritoneum. The aetiology of endometriosis is uncertain but there is increasing evidence that transforming growth factor (TGF)-β plays a major role.OBJECTIVE AND RATIONALEA descriptive r...
Source: Human Reproduction Update - July 6, 2017 Category: OBGYN Source Type: research
