1.1 BACKGROUND OF THE STUDY The menstrual cycle is the cycle of natural changes that occurs in the uterus and ovary as an essential part of making sexual reproduction possible. (Lentz et al., 2012) Its timing is governed by endogenous(internal) biological cycles. The menstrual cycle is essential for the production of eggs, and for the preparation of the uterus for pregnancy. (Lentz et al., 2012) The cycle occurs only in fertile female humans and other female primates. In human females, the menstrual cycle occurs repeatedly between the ages of menarche, when cycling begins, until menopause, when it ends.In humans, the length of a menstrual cycle varies greatly among women (ranging from 21 to 35 days), with 28 days designated as the average length. (Anderson et al., 2003) Each cycle can be divided into three phases based on events in the ovary (ovarian cycle) or in the uterus (uterine cycle).[Anderson et al., 2003]. The ovarian cycle consists of the follicular phase, ovulation, and luteal phase whereas the uterine cycle is divided into menstruation, proliferative phase, and secretory phase. Both cycles are controlled by the endocrine system and the normal hormonal changes that occur can be interfered with using hormonal contraception to prevent reproduction. (Klumpet al., 2013)By convention, the length of an individual menstrual cycle in days is counted starting with the first day of menstrual bleeding. Stimulated by gradually increasing amounts of estrogen in the follicular phase, discharges of blood (menses) slow then stop, and the lining of the uterus thickens. Follicles in the ovary begin developing under the influence of a complex interplay ofhormones, and after several days one or occasionally two become dominant (non-dominant follicles atrophy and die). Approximately mid-cycle, 24–36 hours after the Luteinizing Hormone (LH) surges, the dominant follicle releases an ovum, or egg, in an event called ovulation. After ovulation, the egg only lives for 24 hours or less without fertilization while the remains of the dominant follicle in the ovary become a corpus luteum; this body has a primary function of producing large amounts of progesterone. Under the influence of progesterone, the endometrium (uterine lining) changes to prepare for potential implantation of an embryo to establish a pregnancy. If implantation does not occur within approximately two weeks, the corpus luteum will involute, causing sharp drops in levels of both progesterone and estrogen. The hormone drop causes the uterus to shed its lining and egg in a process termed menstruation (Klumpet al., 2013)In the menstrual cycle, changes occur in the female reproductive system as well as in other bodily systems (which can lead to breast tenderness or mood changes, for example). A woman's first menstruation is termed menarche, and occurs typically around age 12-13. The end of a woman's reproductive phase of life is called the menopause, and this commonly occurs somewhere between the ages of 45 and 55 (Sioba´n D et al., 2004).The menstrual cycle is characterized by cyclical fluctuations in the levels of FSH, LH, estrogen and progesterone The hormones are known to have an effect on oxygen carrying capacity, immune response, bleeding and also changes in serum electrolytes which may be responsible for variable physical, psychological symptoms and autonomic changes. It is suggested that stressful situations during ovulatory periods and menstruation may cause increased 17-hydroxy corticosterone levels with resulting eosinopenia (Feuring M et al., 2002) Platelet function is periodically altered during the ovarian cycle due to the influence of progesterone and estrogen on Von Willebrand factor concentrations (Sioba´n D et al., 2004). Ovarian hormones influence almost all the systems of the body. They are known to alter the immune system like depression of the suppressor T cell activity Human & animal studies suggest that there is a change in the distribution of immune cells during different phases of menstrual cycle (Pehlivanoglu B et al., 2001) 5–20% of women reporting severe dysmenorrhea (painful menstruation) which may be associated with reproductive morbidities like infection (Sioba´n D et al., 2004), thus estimation of leucocyte count is an important tool. Females have more asthma throughout the reproductive years. Female sex steroids are pro-inflammatory and will increase the susceptibility to atopy(Sioba´n D et al., 2004),.Red blood cell (RBC)indicesassist in classifying anemias. In general,besuretofullyassess apatient’snutritional status andconsultadietitianforfurther workupand interventionas appropriate. Wound healingcan begrossly affectedbynutritionalanemias,andpatientsmayrequireiron, zinc, and vitaminCsupplementsto promote surgicalwoundhealing.Patients will also re- quire teaching andneed encouragementtoinclude iron rich foods such asliver, red meat, raisins, peas, apricots,kidney beans, andfortifiedcerealsandbreads intheir diets (Sioba´n D et al., 2004).Platelets are irregularly shaped, disk-like fragments of their precursor cell, the megakaryocyte. They are one fourth to one third the size of erythrocytes (1.5–3.0 μm). As megakaryocytes develop, they undergo a process of fragmentation that results in the release of over 1,000 platelets per cell. Several factors stimulate megakaryocytes to release platelets within the bone marrow sinusoids. This includes the hormone thrombopoietin, which is mainly generated by the liver and the kidneys and released in response to low numbers of circulating platelets. Platelets have no defined nucleus but possess important proteins, which are stored in intracellular granules and secreted when platelets are activated during coagulation.Platelet adherence can be initiated by a variety of substances. For instance, factors released by platelets cause the upregulation of adherence proteins (integrins) on endothelial cells. One critical substance released by endothelial cells and also megakaryocytes is called von Willebrand factor. It enhances platelet adhesion to the endothelium by forming a bridge between platelet surface receptors and collagen in the subendothelial matrix. The most common hereditary bleeding disorder is von Willebrand disease, caused by an inherited deficiency of the factor. Ruptured cells at the site of tissue injury release adenosine diphosphate (ADP), causing the aggregation of more platelets, which are, in turn, stabilized by fibrinogen. Clinically, penicillin in high doses can coat platelets and prevent aggregate formation.