Research
Practice Committee of the American Society for Reproductive Medicine and Practice Committee of the Society for Reproductive Endocrinology and Infertility, 2026·Fertility and sterility
Luteal phase deficiency (LPD) is a clinical diagnosis associated with abnormal luteal phase length of ≤10 days. Potential etiologies of LPD include inadequate progesterone duration, inadequate progesterone levels, or endometrial progesterone resistance. Luteal phase deficiency has been described in association with medical conditions, but also in fertile, normally menstruating women. Although progesterone is important for the process of implantation and early embryonic development, LPD has not been proven to be an independent entity causing infertility or recurrent pregnancy loss. Controversy exists regarding the multiple proposed measures for diagnosing LPD, and assuming it can be diagnosed accurately, whether treatment improves outcomes. This document replaces the document of the same name, last published in 2021 (Fertil Steril 2021;115(6):1416-23).
Research
Practice Committee of the American Society for Reproductive Medicine, 2026·Fertility and Sterility
Current strategies for the assessment and treatment of recurrent pregnancy loss are discussed. This replaces the previous document, titled, "Evaluation and treatment a committee opinion," last published in 2012.
Research
Boedeker D et al., 2026·Fertility and sterility
This narrative review examines the evidence for medical optimization of inflammatory conditions, vitamin deficiencies, endocrine disorders, immune dysregulation, oligo-ovulation, and luteal phase factors to improve fertility outcomes in women attempting to conceive through natural or timed intercourse. Overall, there is a paucity of data with respect to these categories among patients pursuing timed intercourse, precluding our ability to draw strong recommendations. However, there is strong evidence supporting treatment of endocrine disorders, specifically overt thyroid dysfunction and hyperprolactinemia, as well as oligo-ovulation. Conversely, treatment of subclinical hypothyroidism is not recommended. The current data are insufficient to support empiric use of antiinflammatory medications, corticosteroids, thyroid hormones, or vitamins or supplements to improve chances of pregnancy in a general infertility population.
Research
Ganci D et al., 2026·Fertility and Sterility
Restorative Reproductive Medicine (RRM) aims to restore fertility by diagnosing and treating the underlying causes of infertility. RRM is frequently promoted as an alternative to assisted reproductive technology (ART), despite uncertainty regarding its comparative effectiveness and safety. Where delayed childbearing and infertility are becoming more common, reliance on optimization of natural physiology alone may delay effective treatment and compromise reproductive outcomes. A systematic review of the current evidence comparing RRM to either ART or unassisted conception is, therefore, essential to inform clinical practice, guideline development, and shared decision-making for patients experiencing infertility. To assess the effectiveness and safety of RRM approaches, evaluated as a whole, rather than as individual components, compared with ART and medically unassisted conception in couples experiencing infertility. A systematic literature search of MEDLINE, Embase, CENTRAL and the Journal of Restorative Reproductive Medicine from inception to 28 November 2025. We included randomized control trials (RCTs) or nonrandomized comparative studies evaluating reproductive and safety outcomes of RRM as a unified treatment, compared with either ART or expectant management (attempted medically unassisted conception). Two reviewers independently screened titles, abstracts and full texts with disagreements resolved by a third reviewer. We retrieved 724 records, of which 16 studies underwent full-text review. No RCTs or comparative observational studies were identified. All 16 full-text studies were excluded for an ineligible study design (no control group); most were cohort studies in which all participants underwent RRM. Ten studies reported reproductive outcomes; nine of these made claims regarding the benefits or effectiveness of RRM. None of these claims were supported by the study designs used, as the lack of a comparison group precludes reliable estimation of treatment effects. Consequently, these studies cannot provide valid estimates of RRM success rates, nor permit any meaningful inference about its effectiveness relative to unassisted conception or ART. Large-scale RCTs or prospective cohort studies reporting effectiveness and safety outcomes are required to inform evidence-based fertility guidelines. There are no comparative studies to support reliable estimates of the safety and effectiveness of RRM compared with ART or medically unassisted conception for couples experiencing infertility.