ABSTRACT
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<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<0.0001). Other variables that also showed
significant association were season of birth, NVP, breastfeeding, contraception,
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educational level and number of elder brothers (P<0.05). All other variables found no
association although age at menopause increased with age at first birth.
TABLE OF CONTENTS
Cover page ————————————————————————————- i
Title page ————————————————————————————– ii
Declaration ———————————————————————————— iii
Certification———————————————————————————— iv
Dedication ————————————————————————————- v
Acknowledgement ————————————————————————— vi
Abstract ————————————————————————————— viii
Table of Contents —————————————————————————- x
List of Tables ——————————————————————————— xiv
Abbreviations ——————————————————————————— xv
CHAPTER ONE
1.1 Background of study ———————————————————————- 1
1.2 Statement of research problem ———————————————————- 6
1.3 Significance of the study —————————————————————– 6
1.4 Justification ——————————————————————————– 6
1.5 Aims and objectives of the study ——————————————————- 7
1.6 Study hypothesis ————————————————————————– 7
1.7 Limitations ——————————————————————————— 8
CHAPTER TWO
2.0 Literature review ————————————————————————- 9
2.1 Overview of nausea and vomiting of pregnancy ————————————- 9
2.2 Aetiology and pathophysiology of nausea and vomiting of pregnancy ——— 9
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2.2.1 Hormonal causes ———————————————————————- 9
2.2.2 The vestibular system —————————————————————- 13
2.2.3 Gastro intestinal tract (GIT) ——————————————————— 14
2.2.4 Immunology ————————————————————————— 17
2.2.5 Behavioural and psychological factors ——————————————– 18
2.2.6 Nutritional deficiency —————————————————————- 19
2.2.7 Anatomy ——————————————————————————- 19
2.2.8 Evolutionary view point (adaptation) ———————————————- 20
2.2.9 Genetic factor ————————————————————————– 22
2.2.10 Ethnicity / socio-economic status ————————————————- 23
2.2.11 Demographic factors —————————————————————– 26
2.3 Effect of nausea and vomiting of pregnancy —————————————– 27
2.4 Management options for nausea and vomiting of pregnancy ———————- 29
2.4.1 Non-pharmacologic remedies ——————————————————– 30
2.4.2 Drug therapy ————————————————————————— 31
2.4.3 Complementary and alternative management ————————————- 32
2.5 Menopause ——————————————————————————- 33
2.5.1 Factors that influence age at menopause ——————————————- 35
2.5.1.1 Demographic characteristics —————————————————— 35
2.5.1.2 Reproductive correlates ———————————————————— 36
2.5.1.3 Anthropometric factors ———————————————————— 38
2.5.1.4 Handedness ————————————————————————– 38
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CHAPTER THREE
3.0 Materials and method —————————————————————— 40
3.1 Subjects ———————————————————————————- 40
3.2 Methods ———————————————————————————- 40
3.2.1 Determination of NVP and menopause ——————————————- 41
3.2.2 Anthropometry ———————————————————————– 41
3.3 Data analysis —————————————————————————- 41
CHAPTER FOUR
4.0 Results ———————————————————————————— 43
CHAPTER FIVE
5.0 Discussions ——————————————————————————– 68
5.1 NVP and anthropometric characteristics ———————————————- 68
5.2 NVP and reproductive characteristics ————————————————- 68
5.3 NVP and socio-demographic factors ————————————————– 70
5.4 Menstrual status and incidence/prevalence of NVP ——————————— 7I
5.5 Effect of nausea and vomiting of pregnancy —————————————— 72
5.6 Management option for NVP ———————————————————– 72
5.7 Age at menopause ———————————————————————— 73
5.8 Menopause and socio-demographic characteristics ———————————- 74
5.9 Menopause and reproduction ———————————————————– 76
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CHAPTER SIX
6.0 Summary, conclusion and recommendation——————————————- 78
6.1 Summary and conclusion —————————————————————- 78
6.2 Recommendation ————————————————————————- 80
References ————————————————————————————- 81
Appendices ———————————————————————————— 96
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF STUDY
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.
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
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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
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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.
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
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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).
In evolutionary history, a long post-reproductive lifespan is a characteristic feature in
the life history of human females, which is not shared with other primates. The timing
of this adaptation has also been proposed since it does not occur in our nearest
relative, the chimpanzee, Pan Troglotytes in particular the Bonobo, Pan Paniscus.
Therefore, it seems likely that the evolutionary pressure that led to this adaptation,
menopause, occurred sometime after we parted company from our common ancestor
around six million years ago (6 mya) (Brunet et al., 2002). In recent times, mans quest
to find answers about him has generated a lot of questions one of which is the ultimate
cause of menopause since selection pressures have pushed several species to
maximize reproductive success rather than optimizing longevity (Vaupel et al., 1998).
This has been the focus of much study as our knowledge about the mechanisms
underlying menopause has largely been confined to ovarian exhaustion, which
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involves the progressive loss of Oocytes beginning before birth and continuing to the
age of menopause. However, a number of evolutionary explanations have been
generated. Commonly cited is the mother and grandmother hypothesis which propose
that menopause was an adaptive response to changes that led to the divergence of
humans from their ancestors (Williams, 1957). This was based on observations such
as the long-dependency time of human infants, early age of weaning of human
neonates, high maternal mortality rate in child birth with increase in age (Grimes,
1994), the supportive role of grandmothers in childcare, and intergroup female
transfer. Furthermore, when the human species took up a bipedal gait as an adaptive
mechanism, they did so at the expense of their pelvic brim; reducing the anteroposterior
diameter of the pelvis which has increased the risk of childbirth which
increases with advance in age. Hence, menopause could have ensued as a check to the
danger of this adaptation; a bipedal gait.
The average age of menopause among Nigerian was estimated at 49 years which is
slightly lower than the typical age of 51 for many developed countries (Ozumba et al.,
2004). It has been found that mortality risk for women who had their natural
menopause before the age of forty is nearly twice as high as for those who
experienced menopause at age 50-54 (Snowdon et al., 1990). This may account for
the short life expectancy of 47.7 years in Nigerian women. A variety of studies
(Bromberg et al., 1997; Stanford et al., 1987; Whelan et al., 1990) also demonstrates
that, along with other factors, the age at menopause correlates positively with parity.
Moreso, Kirchengast (1992) found a positive correlation between age at last and first
birth and age at menopause.
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1.2 STATEMENT OF RESEARCH PROBLEM
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.
1.3 SIGNIFICANCE OF THE STUDY
I. This study is to describe a typical reproductive history of a Nigerian female
II. Provide a reference value on the prevalence of nausea and vomiting of
pregnancy among Nigerian population and its incidence among sub-ethnic
group.
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.
1.4 JUSTIFICATION
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
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the observed pattern of NVP among different ethnic group with respect to their
environment should be studied.
1.5 AIMS AND OBJECTIVES OF THE STUDY
I. To determine the prevalence and incidence of nausea and vomiting of
pregnancy in Nigeria and its subpopulations based on ethnicity.
II. To determine the association between reproductive characteristic and certain
socio-demographic factors with NVP and menopause.
III. To investigate the use of herbal remedies in the management of nausea and
vomiting of pregnancy in Nigeria.
1.7 STUDY HYPOTHESIS
I. There is an increase incidence of NVP among gravid women in recent times
than year’s back.
II. Women of low socio-economic status are less likely to suffer nausea and
vomiting of pregnancy than those of higher socioeconomic status.
III. There is no association between ethnicity and nausea and vomiting of
pregnancy.
IV. The average menopausal age for Nigerian women will be less than that
reported for the black race.
V. Other factors other than age are more determining of menopausal onset.
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1.7 LIMITATIONS
Some limitations encountered include;
I. Gaining ethical approval and authorization from some hospitals, institution and
community
II. Lack of willingness and cooperation from the women
III. Problem of recalling event on the part of the women and inability of the women to
fill out the questionnaires completely.
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