Prolactin as a neuroendocrine clue in sexual function of women across the reproductive life cycle: an expert point of view

Thyroid diseases and female sexual dysfunctions

INTRODUCTION

Female sexual dysfunctions (FSDs) have received little attention in the context of thyroid diseases, despite the high prevalence of both conditions.

OBJECTIVES

This review aims to update and summarize the state of knowledge on the association between thyroid diseases and FSDs and to investigate the complex mechanisms through which thyroid hormone imbalance can impact female sexual health in the context of the biopsychosocial model.

METHODS

A comprehensive literature search was performed through the PubMed, MEDLINE, and Scopus databases, using the following keywords: "female sexual function," "sexual dysfunction," "hypoactive sexual desire disorder," "thyroid disease," "thyroiditis," "hypothyroidism," and "hyperthyroidism."

RESULTS

To date, well-designed studies that describe the relationship between FSDs and thyroid disorders are lacking. However, despite the limitations on available studies, current data indicate that sexual alterations are frequently associated with thyroid diseases in women. A complex interplay of direct and indirect hormonal and nonhormonal mechanisms has been hypothesized, including hormonal changes, neurotransmitter imbalance, reduced nitric oxide release, mood disorders, and other systemic consequences of both hypothyroidism and hyperthyroidism. Thyroid hormone receptors have also been identified in the genitourinary system.

CONCLUSIONS

In a clinical setting, physicians should investigate the sexuality of patients consulting for thyroid disease. At the same time, an evaluation of thyroid function should be performed in patients presenting with FSD, especially after menopause, when the risk of thyroid diseases and FSDs increases strongly.

Longitudinal changes in sexual desire and attraction among women who started using the Natural Cycles app

Many women experience sexual side effects, such as decreased libido, when taking hormonal contraceptives (HCs). However, little is known about the extent to which libido recovers after discontinuing HCs, nor about the timeframe in which recovery is expected to occur. Given that HCs suppress the activities of multiple endogenous hormones that regulate both the ovulatory cycle and women's sexual function, resumption of cycles should predict libido recovery. Here, using a combination of repeated and retrospective measures, we examined changes in sexual desire and partner attraction (among partnered women) across a three-month period in a sample of Natural Cycles users (Survey 1: n = 1596; Survey 2: n = 550) who recently discontinued HCs. We also tested whether changes in these outcomes coincided with resumption of the ovulatory cycle and whether they were associated with additional factors related to HC use (e.g., duration of HC use) or relationship characteristics (e.g., relationship length). Results revealed that both sexual desire and partner attraction, on average, increased across three months after beginning to use Natural Cycles. While the prediction that changes in sexual desire would co-occur with cycle resumption was supported, there was also evidence that libido continued to increase even after cycles resumed. Together, these results offer new insights into relationships between HC discontinuation and women's sexual psychology and lay the groundwork for future research exploring the mechanisms underlying these effects.

Identification of genetic markers associated with hyperketonemia patterns in early lactation Holstein cows

Ketosis, evidenced by hyperketonemia with elevated blood β-hydroxybutyrate (BHB) levels, is a significant metabolic disorder of dairy cattle, typically diagnosed within the first 6 weeks post-calving when high energy levels are essential to milk production. Our study aimed to identify genetic markers linked to hyperketonemia (HYK) patterns in Holstein cows during early lactation and compare these to HYK-negative cows. We screened 964 cows for HYK using a threshold of BHB ≥1.2 mmol/L during the first 2 weeks postpartum (screening period, SP). Cows that tested negative initially were retested the following week. Cows were deemed HYK-negative (CON group) if BHB levels were below 1.2 mmol/L in both tests, while those with BHB levels exceeding this threshold at any test were treated and classified as HYK-positive (HYK+). Post-treatment, HYK+ cows were monitored for two-week follow-up period (FP) and classified based on their recovery: cured (CUR; consistently low BHB), recurrent (REC; fluctuating BHB levels), severe (SEV; high initial BHB that decreased), or chronic (CHR; persistently high BHB). Using 489 cows that were genotyped, a GWAS was conducted using GCTA software, revealing significant associations of several SNPs across different HYK patterns when compared to the CON group. These SNPs were primarily linked to genes affecting milk traits and were enriched in biological pathways relevant to protein glycosylation, inflammatory response, glucose homeostasis, and fatty acid synthesis. Our findings highlight genomic regions, potential candidate genes, and biological pathways related to ketosis, underscoring potential targets for improving health management in dairy cattle. These insights could lead to better strategies for managing ketosis through genetic selection, ultimately enhancing dairy cattle welfare and productivity. Further research with a larger number of cows is recommended to validate these findings and help confirm the implicated SNPs and genes.

Pharmacotherapy for female sexual dysfunctions (FSDs): what is on the market and where is this field heading?

INTRODUCTION

Female sexual dysfunctions (FSDs) are common in women of any age and have a huge impact on quality of life and relationships. They have a multifaceted etiology limiting the development of pharmacotherapies with a high rate of effectiveness. Safety issues are also a concern.

AREAS COVERED

The authors report the most recent advances in pharmacotherapy for premenopausal and postmenopausal women with a main focus on hypoactive sexual desire disorders (HSDD) and associated sexual symptoms. Good levels of evidence have emerged for psychoactive agents, such as flibanserin and bremelanotide, as well as hormonal compounds (transdermal testosterone). The authors also report briefly on intravaginal DHEA (prasterone), local estrogen therapy (LET), and ospemifene to manage effectively vulvovaginal atrophy/genitourinary syndrome of menopause (VVA/GSM). In addition, they discuss promising therapeutic options highlighting the main reasons that hamper the availability of new labeled products. Finally, they include the importance of the multimodal approach to address FSDs.

EXPERT OPINION

Approved pharmacotherapies for FSD are limited. Validated multidimensional instruments and adequate objective measures of physical and mental responses to sexual external and internal incentives are mandatory to identify women suitable to chronic or on-demand treatments and to assess their pattern of response in research and practice.

Thyroid, Adrenal, PRL Impairments and Ovarian Function

Endocrine axes (prolactin, thyroid and adrenal axes) directly and indirectly modulate and drive human female central functions, mainly behavior and reproduction. Though having distinct abilities, they greatly act both at peripheral as well as at neuroendocrine levels, so as to participate in the control of reproduction. Any event that changes these balanced activities produces specific peripheral signals that induce abnormal functions centrally, thus triggering menstrual disorders such as oligomenorrhea or amenorrhea. It is clear that the knowledge of the relationships that exist between the different endocrine axes becomes essential for the choice of therapeutical approach. This review aims to focus on the main aspects of the physiopathology of the endocrine diseases that might be at the basis of that interference with female reproductive capacity.