COMPARATIVE ANALYSIS OF THE UTERINE MENSTRUAL CYCLE AND THE HEMATOLOGICAL INDICES OF STUDENTS IN THE UNIVERSITY OF BENIN

Thesis Overview

1.0 INTRODUCTION

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 (Lentzet 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 menarch, 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 note-Widmaier-3"nderson 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 (Klumpetet 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 of hormones, 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 (Klumpetet al., 2013).

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 electrolyte 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´net 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 (Pehlivanogluet al., 2001). 5–20% of women reporting severe dysmenorrhea (painful menstruation) which may be associated with reproductive morbidities like infection (Sioba´net 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´net al., 2004).

In developing countries, abnormal uterine bleeding appears to affect about 5–15% of women of reproductive age. It is a major cause of gynecological morbidity, affecting up to one in five women some point during their reproductive life span Reproductive-aged women of about 9-14% have blood loss that exceeds 80 ml (Rajneeet al., 2010) and prolonged and excessive bleeding may provoke or exacerbate anaemia and in a certain percentage of cases, may eventually be life threatening if left untreated, thus there arises a need to estimate Haemoglobin, Red Blood Cell count and ESR during the menstrual cycle. The lack of awareness about the potential importance of reducing menstrual flow when women are anaemic and lack of knowledge among women about treatment alternatives is of some concern. The maintenance of different blood corpuscles at normal levels during the menstrual cycle is necessary. Therefore, in the present study, haematological modulation in the different phases of menstrual cycle was studied. (Silverthornet al., 2013 and Sherwood et al., 2013).