Serum Thyroid Hormone Level in Women with Nausea and Vomiting in Early Pregnancy
The aim of this study was to establish the relationship between the serum
Thyroid Stimulating Hormone (TSH) and thyroxin (T4) which reflect thyroid
function assessment, with nausea and vomiting, among pregnant women in
early pregnancy. In present study 60 pregnant women without nausea and
vomiting compared with 60 pregnant women with nausea and vomiting during
2007-2008. Two groups of case and control were matched. Patients with
nausea and vomiting did not have significant differences when compared
with control subjects in TSH level, the data from this investigation indicated
that, T4 level elevated among 34 subjects (56.6%) with nausea and vomiting
compared to 20 subjects (33.3%) of women without nausea and vomiting.
These data suggest that there is a role for elevated T4 in nausea and
vomiting among pregnant women, in early pregnancy.
Nausea and vomiting of pregnancy (NVP) is the most common medical condition
of pregnancy, affecting up to 80% of all pregnancies to some degree. In
most cases it subsides by the week 16 of pregnancy, although up to 20%
of women continue to have symptoms throughout pregnancy. Severe NVP (hyperemesis
gravidarum) affects <1% of women and in some severe cases can require
hospitalization and rehydration of fluids. Women suffer not only physically
but also psychologically, which has been documented in a number of studies.
In addition, some women have decided to terminate their pregnancy rather
than tolerate severe symptoms. Even less severe cases of NVP can have
significant adverse effects on the quality of a women` s life, affecting
her occupational, social, domestic functioning and general well being
(Sheehan, 2007). Hyperthyroidism is frequently encountered in hyperemisis
gravidarum, but its relation to the cause of hyperemisis is unknown. The
etiology of nausea and vomiting and its sever form, hyperemis gravidarum,
which in emergency cases require intravenous rehydration therapy, remain
unclear. For many years there has been speculation that either Human Chorionic
Gonadotropin (HCG), or, estradiol might be causative, HCG has been suspected
chiefly based on the observation that its peak coincides the peak of nausea
and vomiting. The pharmacological effect of estrogen including nausea
and vomiting has also made it a likely candidate within the last decade
biochemical hyperthyroidism associated with nausea and vomiting and its
sever form hyperemisis gravidarum has been described and also attributed
by some to HCG because of the known thyrotropic activity of this hormone
(Verberg et al., 2005; Haddow et al., 2008). Thyroid disorder
constitute one of the commonest endocrine problems found in pregnant women.
The diagnosis of hyperthyroidism in pregnancy may be often challenging
due to the fact that its symptoms mimic many of normal pregnancy complaint.
Moreover, some forms of hyperthyroidism occur, exclusively during this
period (Krysiak et al., 2006 ).
Thyroid disorder are observed more frequently in women compared with
men in particular during the childbearing period. It is therefore not
unusual to encounter thyroid function abnormalities during a routine laboratory
evaluation carried out for pregnant women, which can be one of the causative
factor for nausea and vomiting during pregnancy. The aim of this present
study was to investigate the role played by, Thyroid Stimulating Hormone
(TSH) and thyroxin (T4), in nausea and vomiting, which is the most medical
condition of pregnancy.
MATERIALS AND METHODS
In present study, 60 pregnant women, in their early pregnancy with nausea
and vomiting as case and 60 matched pregnant women without any nausea
and vomiting as control, were selected from patients referred to the Danesh
medical diagnostic research center during 2007-2008 in Gorgan, the capital
city of Golestan province located in the south-east of Caspian sea, in
the north-east of Iran. Two milliliter of venous blood taken and serum
was separated after centrifugation, following confirmation of pregnancy,
a questionnaire was given to each women, which contain demographic questions
and whether the pregnant women had nausea and vomiting. Hormonal determination
of TSH and T4 were carried out on 60 case and 60 control pregnant women,
using Enzyme-linked Immunosorbant Assay (ELISA) technique. The gathered
data of TSH and T4 entered into the computer, SPSS-11.5 software were
used to analyze the results and compare between two groups.
The normal range for TSH and T4 were 0.32-5.2 mIU L-1 and
4.7-12.5 μg dL-1, respectively. The T4 higher than 12.5
μg dL-1 or TSH below 0.32 mIU L-1 considered
In the first year, study hormonal determination of TSH and T4 of 60 pregnant
women with nausea and vomiting as a case and 60 as pregnant women without
any nausea and vomiting control subjects were determined. The information
regarding thyroid function among the case and control subjects presented
in (Table 1, 2).
Women with nausea and vomiting differed with respect to their Serum T4
level (Table 1). It means that 56.6% of case group had
elevated T4 level Compared to 33.3% of Control group. There were not any
meaningful differences regarding TSH level among case and control group
(Table 2). The results related to the thyroid function
among women with nausea and vomiting and control groups are also presented
in Table 3.
||Serum T4 level among case (with nausea and vomiting)
and controls pregnant women
||Serum TSH level among case (with nausea and vomiting)
and controls pregnant women
||Mean Serum T4 and TSH level among case (with nausea
and vomiting ) and control pregnancy women
In the present study the mean age of case and control did not have any
differences, (26.0 year verses 26.1 year). In this study about 80% of
whole sample population had 1 to 2 gravid (50% with one and 30% with two
gravid ) and there was not any noticeable differences among case and control
groups; Regarding parity 62 and 40% were in their first and second parity
respectively, also there was not any noticeable differences among the
case and control pregnant women.
The sample population in this study were in their early pregnancy, 81%
in their 5 weeks of pregnancy and cases had mild to moderate nausea and
vomiting (50, 22% mild and moderate, respectively) none of present cases
had the sever form of nausea and vomiting which defined as, hyperemesis
Nausea and vomiting are common during pregnancy and when severe enough
to require intervention, may develop into the syndrome known as hyperemesis
gravidarum. when the diagnosis of hyperemesis is considered, a careful
search for secondary causes is necessary. Among the list of secondary
causes includes hyperthyroidism. Up to 90% of pregnant women experience
NVP, the pathogenesis remains poorly understood with multifactorial theories
proposed combining both biologic and psychological factors. Thyroid disease
requires special care for pregnant women or those desiring pregnancy.
Biochemical hyperthyroidism is a common self-limited finding in pregnant
women with nausea and vomiting and its sever form of hyperemesis gravidarum.
Patients with these findings did not have clinical condition indicative
of Grave`s disease or thyroid antibodies, including TSH receptor antibodies,
antimicrosomal antibodies and antithyroglobulin antibodies. In a study
cohichis performed on the role of HCG on nausea and vomiting and its sever
form, hyperemesis gravidarum it was argued that, HCG ultimately stimulate
the thyroid gland and if nausea and vomiting is frequently seen among
pregnant women with greater HCG concentration, it is due to hyperactivity
of thyroid gland. In the later investigation it was also shown that the
degree of thyroid stimulation as indicated by clinical test varied directly
with the severity of nausea and vomiting over the range of symptoms from
no nausea and vomiting to severe hyperemesis. Other study by Fantz et
al. (1999) also indicated that thyroid dysfunction during pregnancy
among some women cause sever vomiting and the proper use of laboratory
tests for the diagnosis of thyroid dysfunction in the pregnant women,
seem to be necessary. In other study on the role of thyroid hormone in
pregnant Chinese women, it was shown that also maternal age and all hormones
were significantly different between the pregnant women with nausea and
vomiting and the control group, however the analysis indicated that only
age, thyroxine and thyroid stimulating hormone, were Significant independent
variables, Panesar et al. (2001) concluded that human chorionic
gonadotropin is not independently involved in the etiology of nausea and
vomiting and its sever form hyperemesis gravidarum, but may be indirectly
involved by its ability to stimulate the thyroid gland. In other study,
in Italy it is shown that, transient hyperthyroidism of hyperemesis. gravidarum
is a self-limiting hyperthyroidism occurring in the context of hyperemesis
gravidarum, which consist of 40 to 70% of thyroid function abnormalities
in pregnancy which is reported mainly responsible by elevation of human
chorionic gonadotropin level (Caffrey, 2000). Hormonal profile of Kuwaiti
women also indicated that thyroid hormones among pregnant women with nausea
and vomiting and its sever form hyperemesis gravidarum significantly higher
(Al-Yatama et al., 2002 ).
Morning Sickness and thyroid function even in normal pregnancy among
Chines women in early pregnancy demonstrated that, a significant increase
in serum T4 and a decrease in serum TSH were observed relative to the
level in nonpregnant controls, (Pansear et al., 2001). On other
hand there are some reports which disputed if, hyperemesis patients and
pregnant women with mild nausea and vomiting differ from asymptomatic
pregnant women with respect to thyroid function (Verberg et al.,
2005) but there are huge reports and evidences that show hyperthyroidism
play an important role in causing nausea and vomiting and its sever form
hyperemesis gravidarum (Glinoer et al., 1993; Verberg et al.,
2005; Goodwin et al., 1992).
The results of present study are in agreement with the important role
of hyperthyroidism in stimulating nausea and vomiting. According to our
finding, when the thyroid hormone level of two groups of pregnant women
with nausea and vomiting and without nausea and vomiting, are compared,
it is found in particular that the case group differ from controls in
respect to T4 serum level with regard to many reports which are mentioned
in this article, we argue that hyperactivity of thyroid gland and production
of higher level of thyroxin may be responsible for the nausea and vomiting
during pregnancy, among our sample population. It should be mentioned
that hormonal change and metabolic demand even during normal pregnancy
results in profound alteration in the biochemical parameters of thyroid
function (Verberg et al., 2005).
For the thyroidologist, pregnancy can be viewed as a prolonged physiological
condition in which a combination of events concur to modify the thyroidal
economy. Such events may act independently, synergistically, or even antagonistically
to produce subtle or major thyroidal effects. Furthermore, these events
take place at different time points during gestation, resulting in complex
effects that may be seen only transiently or, by contrast, that persist
until term (Verberg et al., 2005). Present data demonstrated that
the mean. TSH concentration did not have significant differences among
case and control group, but there was a noticeable change regarding about
mean concentration of T4, (11.3 vs 10.3 μg dL-1). In our
sample population 34 women from case group presented with nausea and vomiting
(56.6%) had elevated T4 level and among control 20 women (33.3%) had elevated
T4 level, which indicated that elevation of thyroxin level among pregnant
women in their early pregnancy, can be a factor in this problem. In our
study we found that the suppressed TSH were found to be 10% among case
and control group (<0.32 mIU L-1) and there was not any
differences in this regard. the reason behind this observation may be
due to level of hCG among our sample population, as far as the pregnant
women in this study were in their early pregnancy mostly up to 5 weeks
of gestatio and there was not enough time for the hCG. Hormone to reach
its highest concentration to be able to stimulate the thyroid gland and
ultimately suppress the TSH level. There are various reports, which indicated
the TSH-like activity of hCG. The references which have been mentioned
above explaining about the investigation carried out on the role of hCG
in this regard, which reports about the role of chorionic Gonadotropin
in transient hyperthyroidism of hyperemesis gravidarum, but in our study
we worked on those pregnant women whom had only mild-moderate nausea and
vomiting and almost none of them had sever form of nausea and vomiting
therefore the reason for our observation, which did not show any change
of TSH level among case and control may be due to the nature of disorder
among pregnant women. Finally on the basis of our results. we can argue
that in this study.
||The elevated T4 can be responsible for nausea and vomiting and our
findings are in consistent with numerous reports which have already
been published in various part of the world
||Also TSH were suppressed among some of our sample population in
case and control groups, but because this study were mainly among
the women in their early Pregnancy and due to low level of hCG hormone,
we did not find significant change of TSH level, among cases and controls
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