Thesis Abstract

<p>            <b>    ABSTRACT&nbsp;</b></p><p>This study investigated some anthropometric and reproductive characteristics associated with nausea and vomiting of pregnancy (NVP) and menopause among Nigerian women. Subjects for this study were drawn from the three major ethnic groups in Nigeria and were divided into two groups viz; a prospective study group (n = 344) which constitute gravid women and a retrospective group (n = 324) which consist of menopausal women. Data was collected through questionnaire via oral interview and recall from these women while anthropometric variables were obtained following standard protocol. The result showed that an early menarcheal age, higher educational level, increased parity and age at menopause significantly (P&lt;0.05) association with NVP in one group but not in the other. Although not significant, a higher proportion of women born in wet season, having a higher economic status, an early child birth and carrying female foetuses reported having NVP. So also were variations in the ethnic report of NVP among the study population. This study also suggest a high prevalence (43.71%) of NVP among Nigerian women and an increased incidence over the years with women of Igbo origin having the highest incidence (53.91%) and Hausa’s the least incidence (34.80%). NVP was found to impose some limitation and emotional challenge on these women with exposure to certain smell and certain food being the most aggravating factor. Both pharmaceutical and complimentary medicines were used for management of NVP and lying down was a common manoeuvre as management among those who did not use drugs. Factors found to significantly associated with the age at menopause are religion, ethnicity, parity and age at marriage (P&lt;0.0001). Other variables that also showed significant association were season of birth, NVP, breastfeeding, contraception, educational level and number of elder brothers (P&lt;0.05). All other variables found no association although age at menopause increased with age at first birth. <br></p>

Thesis Overview

<p>1.0&nbsp;<b>INTRODUCTION</b></p><p><b>1.1 BACKGROUND STUDY&nbsp;</b></p><p> Anthropometric characteristics have been shown to be possible predictors of reproductive success in human female species and this has been widely studied. Height, weight and body mass index (BMI) has been associated with increased parity, twinning and higher fertility in women (Danborno and Oyibo, 2008; Pollet and Nettle, 2008; Swami et al., 2008). Other has also considered certain reproductive characteristics as probable markers for biological determinants of longevity, especially, early fecundity and late menopause (Doblhammer et al., 1999). Reproductive history has been tied to and now well known to determine the existence of the female species as the female’s reproductive characteristics is known to determine her survival, fitness, adaptation, and aging and to an extent, survival and reproduction of her offspring from evolutionary perspective (Voland and Engel 1986). However, studies have shown that approximately one-quarter of variation could be attributed to genetic factors and three-quarters to unknown environmental factors (Herskind et al., 1996). Among other reproductive characteristics, age at menarche, menopause and nausea and vomiting of pregnancy has been proposed by researchers to be influenced by demographic, environmental, anthropometric and other factors (Simondon et al., 1997; Danborno and Oyibo, 2008; Parazzini et al.1992; Luoto et al. 1994) other than the gene.&nbsp;<br></p><p> Nausea and vomiting of pregnancy (NVP) commonly called “vomitus metatinus gravidarum (morning sickness)” is known to occur between the 4th and 10th week of gestation and is resolved about the 20th week of gestation. The aetiology of NVP is poorly understood (Lacasse et al., 2009), however, according to Broussard and Richter (1998), its association with pregnancy was documented on papyrus dating as far back as 2000 BC, the earliest reference being recorded in ‘Soranus’ Gynaecology from the second century AD. Report has it that about 80% of all pregnant women will experience some form of nausea and vomiting during pregnancy (Verberg et al., 2009) and currently, severe nausea and vomiting known as hyperemesis gravidarum which is characterized by severe intractable vomiting requiring hospitalization has become the third leading cause of hospitalization during pregnancy due to dehydration, malnutrition, and electrolyte imbalances (Bennett et al., 1998) even though the evolutionary adaptation theory proposes that mild degrees of NVP causes no harm to the mother or embryo and therefore may be a beneficial adaptation rather than a disease or disorder which have probably evolved to serve a useful function of protecting the pregnant woman and embryo from food-borne infections and toxins, teratogens and substances capable of terminating pregnancy (Sherman and Flaxman, 2002). Plausible, the evidence showing that women with NVP have a more positive pregnancy outcome, may have provided additional support for the evolutionary adaptation theory and natural selection (Tierson, 1997). However, the book of Genesis says only that women shall labour and deliver in pain but nothing about the immediate distress of conception was mentioned, with the growth of cities and the hybridization of an urbanized human population, nausea and vomiting of pregnancy have emerged as a common phenomenon. It has been observed that in contemporary, widely dispersed foraging groups such as the Bushmen of South western Africa and of some Amazonian Amerindian tribes with well-documented genetic homogeneity, nausea and vomiting of pregnancy are rare. This contrast significantly with similar groups living in more stable, sessile villages with larger populations and wider contacts to outside people, resulting in diverse, more complex choices for genetically heterogeneous mate selection such as ours, hence, nausea and vomiting of pregnancy has become common and may progress to maternal morbidity and mortality (Richard, 2002) since implantation and placentation now occur in gestations where immunogenetic differences between mother and foetus are not as subtle as they once were in small, genotypically homogeneous tribal groups. Therefore, maternal immunomodulation necessary for successful survival of the foetus is no longer asymptomatic but associated with dysphoria and what we have come to accept as normal "morning sickness". Conception has thus, become easier to recognize but harder to accommodate. Profet (1992) defining nausea and vomiting of pregnancy as the presence of food aversions, nausea and or vomiting, also argued that because not all modern toxins emit the cues that are necessary for triggering the aversions of pregnancy sickness and because the plant foods have become less toxic through selective breeding, the selection pressures maintaining the mechanisms for detecting and avoiding Pleistocene toxins during pregnancy may have been decreasing since the advent of agriculture. She also speculated that the variability in pregnancy sickness among women in industrial societies may be due to variations in dietary toxicity or decreasing selection pressures for detecting and avoiding substances that emit Pleistocene cues of toxicity and proposed a comparison of variability among women in industrial societies and among women in hunter-gatherer societies in order to determine whether pregnancy sickness is more variable among the former.<br></p><p> The incidence of NVP varies across different countries (Jordan et al., 1995) and ethnic differences in the reporting of health problems has become vital in order to find out the reason why patients in same environment experience diseases and treatment differently, and also to expand approaches for the improvement of public health (Burchard et al., 2003). Nausea and vomiting of pregnancy has been associated with race and ethnicity and the reason is unknown but it has been proposed that the difference in incidence between ethnic groups could be accounted for by important socioeconomic variables (Klebanoff et al., 1985; Louik et al., 2006). Some researchers have also speculated that genetic factors may explain the difference as to why the degree of occurrence varies among ethnic groups (Vilming et al., 2000; Viknes et al., 2010). Apart from the ethnic difference in the occurrence of NVP, some anthropometric and demographic factors have also been associated with NVP as studies have reported association between maternal age, body weight, parity, sex of foetus, family history and experience in previous pregnancy as factors which bears increased risk of developing severe NVP (Vikanes et al., 2008).<br></p><p> <b>1.2 STATEMENT OF RESEARCH PROBLEM&nbsp;</b></p><p>There is increasing interest especially in developing countries on nausea and vomiting of pregnancy and menopause as a recent study proposes that menopause will soon become a mid-life event (Brown, 2010). Also, there is insufficient data on NVP in Nigeria and the complimentary herbal use has not been defined in Nigeria despite the increase use reported among pregnant women. <br></p><p> 1<b>.3 SIGNIFICANCE OF THE STUDY&nbsp;</b></p><p>I. This study is to describe a typical reproductive history of a Nigerian female&nbsp;</p><p>II. Provide a reference value on the prevalence of nausea and vomiting of pregnancy among Nigerian population and its incidence among sub-ethnic group.&nbsp;</p><p>III. Give an idea to what extent the environment contributes to this condition (NVP) when compared with data provided by other researchers for other countries. <br></p><p> <b>1.4 JUSTIFICATION&nbsp;</b></p><p>The increased life expectancy especially in developed countries has re-awakened research into reproductive history as more evolutionary studies propose that there is a trade-off between reproductivity and longitivity. Several investigators reports that there is increased incidence of nausea and vomiting of pregnancy with association to economic status and life style. However, there exist controversies about Blacks or white being most affected. In addition, this study is also based on recommendations of Vikanes et al., (2008) that the difference in incidence between (sub) populations and the observed pattern of NVP among different ethnic group with respect to their environment should be studied. <br></p><p> 1<b>.5 AIMS AND OBJECTIVES OF THE STUDY&nbsp;</b></p><p>I. To determine the prevalence and incidence of nausea and vomiting of pregnancy in Nigeria and its subpopulations based on ethnicity.&nbsp;</p><p>II. To determine the association between reproductive characteristic and certain socio-demographic factors with NVP and menopause.</p><p>&nbsp;III. To investigate the use of herbal remedies in the management of nausea and vomiting of pregnancy in Nigeria. <br></p>