Introduction: Caffeine is considered to be one of the most frequently used pharmacologically active substances in the world. Caffeine is a psychoactive and central nervous system stimuli that has the ability to increase energy, decrease fatigue, promote alertness and wakefulness. Potential role of caffeine's nociceptive properties shows that it may play a relevant role in pain modulation. Although caffeine at dietary levels is not a sufficient analgesic in its own, it has been included in many over-the-counter and prescription drugs. This review addresses caffeine's analgesic properties in pain management.  Results: Caffeine shows relevant role in pain modulation through blocking adenosine receptors which are involved in nociception. Studies show that habitual dietary caffeine consumption results in decreased pain sensitivity.As an adjuvant to commonly used analgesics, caffeine provides an important increase in pain relief in various types of pain such as postoperative dental pain, headaches, or fibromyalgia.Conclusions: In conclusion, caffeine is associated with decreased pain sensitivity. Addition of caffeine to analgesics has resulted in their enhanced analgesic efficacy in pain treatment.

Introduction: Endometriosis is a common gynaecological disorder associated with pelvic pain and sub-fertility, affecting 7-15% of women of reproductive age. The disease is defined as the presence of endometrial-like tissue outside the uterine cavity, primarily on pelvic organs. The aetiology of endometriosis is still uncertain. The disease rarely causes mortality, however, it may have a significant impact on a patient's quality of life. Moreover, several studies have consistently shown that endometriosis is associated with a higher risk of some types of malignancies. Results: Endometriosis shares several molecular characteristics with invasive cancer, such as inflammation, tissue invasion, angiogenesis, dysfunction of immune cells and pro-survival features. Studies have shown that ovarian cancer, especially clear cell, endometrioid and serous, has been associated with endometriosis. Furthermore, the risk of cancer of the uterine cervix has shown to be decreased and the results on the risk of the cancers of uterine corpus or breast are inconsistent. Among non-gynecological cancers, melanoma of the skin, non-Hodgkin-lymphoma, brain and thyroid cancers have also been associated with endometriosis. Conclusions: Research results indicate that women with endometriosis have an increased risk for some types of malignancies, therefore, they should be under strict gynecological control, even many years after menopause. Further research is needed to prove the real risk of different types of malignant tumors among women with endometriosis. In addition, it is necessary to establish periodic examination schedules among these patients in order to prevent certain types of malignancies.

Introduction: Sleep disorders are a big group of disturbances affecting many people in the world. They can appear as insomnia, interrupted sleep, worsened sleep quality or trouble falling asleep. Although they may not seem very dangerous, they lead to various unpleasant complications and even diseases. Cancer is said to be one of the possible sources of the problem. Results: Studies show relationship between cancer and sleep disruptions. They are frequent in lung, head and neck, gynecologic and breast neoplasms. Patients report higher scores of Pittsburgh Sleep Quality Index, insomnia severity scale and Epworth Sleepiness Scale meaning that they can be considered as poor sleepers. In addition, they often develop psychiatric disorders which are linked with higher risk of sleep problems. Conclusions: According to many research, cancer often comes with somnipathies. It should be taken into consideration when planning oncologic treatment and care to obtain the best effects of the therapy.

Many pregnancies in the world are unintentional and some of them end in abortion, hence there is a great need and amount of research on contraceptives. There are many methods of pregnancy prevention for women. However, men also want to be responsible for their reproductive health. Currently, there are few methods of contraception for men (male condoms, vasectomy, withdrawal) and they have their drawbacks, so research on new contraceptives for men is ongoing. Hormonal methods under research include testosterone, nestorone, and DMAU. On the other hand, adjudin, WIN 18.446, BMS-189453 and RISUG are promising methods of non-hormonal male contraception. These substances can be a discovery and a breakthrough in male contraception, they will allow men to better control their fertility and reproductive health, and can also be a suitable solution for couples in which there are contraindications for women to use contraception.

Introduction: Infertility affects millions of people of reproductive age worldwide. Male infertility may be caused by a number of different factors including problems in the ejection of semen, absence or low levels of sperm, or abnormal morphology and movement of the sperm. Environmental and lifestyle factors also have a meaningful impact on male reproductive system. Fertility care should include the prevention, diagnosis and treatment of the disorder. That is why numerous studies have explored the role of vitamin D in regulating the functioning of the reproductive system.Aim of study: Investigation of correlation between Vitamin D and male fertility.Results: Studies consistently show that Vitamin D deficiency has a negative influence on male fertility. Number of trials show that the mean value of Vitamin D serum levels tend to be significantly lower in infertile men compared to fertile men. Vitamin D insufficiency and deficiency has been noticed to be associated with poor semen quality (lower sperm concentrations, lower motility). It became  evident that vitamin D exhibits positive correlation with the male fertility by maintaining the levels of sex hormones, down regulating oxidative stress and up regulating oxidative defence. Supplementation of Vitamin D may improve the quality and function of sperm by increasing its motility and concentration.Conclusions: Although Vitamin D supplementation cannot be considered for treatment of male infertility itself, physicians should take the vitamin serum levels under consideration while providing treatment for infertile male patients.