OOIR: Observatory of International Research

Papers

(The H4-Index of Human Reproduction Update is 39. The table below lists those papers that are above that threshold based on CrossRef citation counts [max. 250 papers]. The publications cover those that have been published in the past four years, i.e., from 2022-05-01 to 2026-05-01.)

Article	Citations
Maternal and perinatal outcomes in twin pregnancies following assisted reproduction: a systematic review and meta-analysis involving 802 462 pregnancies	560
BMI in children aged 1–18 years conceived after ART with fresh and frozen embryo transfer: a systematic review and meta-analyses	167
Comparison of dietary and physical activity behaviors in women with and without polycystic ovary syndrome: a systematic review and meta-analysis of 39 471 women	143
The pathophysiological role of estrogens in the initial stages of pregnancy: molecular mechanisms and clinical implications for pregnancy outcome from the periconceptional period to end of the first t	132
Building a human pluripotent stem cell-based gonadal niche: improving in vitro systems with in vivo insigh	116
What do we mean by preconception health and preconception care in research and policy? A systematic review	112
Functional hypothalamic amenorrhoea and polycystic ovarian morphology: a narrative review about an intriguing association	111
Ultrasonographic criteria in the diagnosis of polycystic ovary syndrome: a systematic review and diagnostic meta-analysis	106
The complicated ART of finding consensus on family-building health policy: a comment on the IFFS consensus document	105
Preconception lifestyle interventions for women—a systematic review and meta-analysis of intervention characteristics and behaviour change techniques	101
Total fertilization failure after ICSI: insights into pathophysiology, diagnosis, and management through artificial oocyte activation	101
What is the optimal GnRH antagonist protocol for ovarian stimulation during ART treatment? A systematic review and network meta-analysis	101
Driving factors in treatment decision-making of patients seeking medical assistance for infertility: a systematic review	95
Temporal trends in sperm count: a systematic review and meta-regression analysis of samples collected globally in the 20th and 21st centuries	88
Reproductive ability in survivors of childhood, adolescent, and young adult Hodgkin lymphoma: a review	85
RNA modifications in female reproductive physiology and disease: emerging roles and clinical implications	78
Obstetric, neonatal, and child health outcomes following embryo biopsy for preimplantation genetic testing	78
Reply: Artificial cycle frozen embryo transfer and obstetric adverse outcomes: association or causation?	76
Intrauterine human chorionic gonadotropin administration before embryo transfer (IHABT): an individual participant data meta-analysis of randomized controlled trials	73
What is the expected live birth rate per thawed oocyte?	73
Assessing the influence of preconception diet on female fertility: a systematic scoping review of observational studies	73
Meiotic recombination: insights into its mechanisms and its role in human reproduction with a special focus on non-obstructive azoospermia	72
Correction to: Evaluating interventions and adjuncts to optimize pregnancy outcomes in subfertile women: an overview review	68
Infertility treatment and offspring blood pressure—a systematic review and meta-analysis	63
Administration of growth hormone improves endometrial function in women undergoing in vitro fertilization: a systematic review and meta-analysis	60

COVID-19 in pregnant women: a systematic review and meta-analysis on the risk and prevalence of pregnancy loss	57
Reply. How much evidence is needed to stop calling endometrial scratching ‘controversial’?	55
Endometrial scratching in women undergoing IVF/ICSI: an individual participant data meta-analysis	52
Reply: What is the expected live birth rate per thawed oocyte?	49
Fertility in transgender and gender diverse people: systematic review of the effects of gender-affirming hormones on reproductive organs and fertility	48
Advances in non-hormonal male contraception targeting sperm motility	47
Molecular insights into sperm head shaping and its role in human male fertility	46
Development and validation of a gonadotropin dose selection model for optimized ovarian stimulation in IVF/ICSI: an individual participant data meta-analysis	46
Does the holy grail of the evidence pyramid vindicate the controversial practice of endometrial scratching or is there room for healthy skepticism?	45
Moving toward totipotency: the molecular and cellular features of totipotent and naive pluripotent stem cells	44
Harnessing omics data for drug discovery and development in ovarian aging	43
Prevalence of polycystic ovary syndrome: a global and regional systematic review and meta-analysis	43
Spermatogonia: a unique stem cell orchestrating species-specific transition from pluripotency to sperm production	43
The epigenetic approach of varicocele: a focus on sperm DNA and m6A-RNA methylation	41
Awareness and attitudes toward fertility preservation among healthcare providers: a scoping review of quantitative evidence	39
Bioengineering trends in female reproduction: a systematic review	39
Epitranscriptomic modifications in embryonic development: insights into natural and ART-induced mechanisms and implications	39
Seminal plasma cytokines in fertile versus infertile men: a systematic review and meta-analysis	39