Hormone Variations During Pregnancy
Hormone Variations During Pregnancy
Introduction
Pregnancy is regarded is one of the most important phase of a women’s life cycle. In addition, pregnancy also encompasses hormonal and physiological changes that are unique in the women’s life cycle. In pregnancy, women experience sudden changes, which includes progesterone and estrogen increases. This also leads to dramatic changes on hormonal functions that affects mood and creates a “glow” among pregnant women. More importantly, hormonal changes during pregnancy poses a significant effect fetal development that also manifests in the changes in physical activities. Having to mention the progesterone and estrogen, medical studies suggests that women produces more of the two aforementioned hormones during pregnancy as compared to the production level when not pregnant. The function of such hormones varies from improving the vascularization of the placenta and uterus to nutrient transfer and fetal maturity. However, estrogen and progesterone are not the only hormones attributed to pregnancy. It was mentioned earlier that pregnancy creates dramatic changes to other hormones that contributes to the fetal development.
This study aims to investigate the hormonal variation during pregnancy, which includes discussions on hormone interaction and production levels. Using related studies and published materials exploring hormone variations during pregnancy, this study will investigate the variation levels of body hormones and how each is attributed to the pregnancy cycle. For convenience purposes, the study will rely on analyzing data from previous studies, thus encompasses the descriptive nature of this research. In addition, the discussion will also emphasize physiological changes in the pregnant women’s body as a result of hormonal variation. This is because hormone variation during pregnancy manifests in physiological attributes.
Literature Review
Hormones are the key drivers in prenatal development. Hormones are chemicals produced by the human body that circulates in the blood and have powerful attributes in regulating physiological functions. The majority of hormonal activities happen in uterus where cyclic changes during the pregnancy phase contribute to the circulating levels of ovarian hormone and metabolism of reproductive tissues (Nasar and Rahman, 2006, p. 2). The study by Nasar and Rahman (2006) explores the hormonal changes in the uterus during pregnancy based on the endocrine profiles of ewe. The systematic review also revealed significant findings pertaining to the concentration of progesterone and oestradiol during the oestrous cycle in the ewe. In addition, the data from presented in the review suggests that progesterone levels in the peripheral plasma of the ewe during pregnancy significantly increases from 2 (ng/ml) to 14 (ng/ml) during 130 days of pregnancy (Bessett et al. as cited from Nasar and Rahman, 2006, p. 4). The findings provide important concepts in this study in terms of providing evidence of hormonal cycles and peak changes during pregnancy, which this study is aiming to determine.
Similarly, the study conducted by Dowling et al. (2000), also presented almost similar findings in acute maternal thyroid hormone changes during pregnancy. The study employed the use of an experimental method where the transient changes in the gene expression of a pregnancy rat’s brain were measured on a molecular and cellular level. The results of the first experiment revealed that there were 11 putative hormone responsive genes in the GD16 cortex region of the fetal brain (Dowling et al, 2000, p. 2258). Furthermore, the experiment also suggests that seven of identified genes were enhanced by T4 while the remaining appears to have been suppressed by maternal T4 (Dowling et al., 2000, p. 2258). The findings from the first experiment are an indication that the anatomical patterns perceived in the fetal genes are regulated by the thyroid hormone of the mother. The second experiment in the study was performed to validate the assumption of the first experiment wherein the effects of thyroid hormone were identified on the overlapping gene patterns of the fetus.
The findings from Dowling et al. (2000) study encompass the important evidence on the function of maternal hormone towards the development of the fetal brain. The underlying concepts in the study ascertain the variation of hormonal activity that occurs during pregnancy. In addition, the findings also establish the factorial elements found in hormonal variation during pregnancy, which provides insights on the interaction between hormones during the pregnancy phase. Although the methods employed in Dowling et al., (2000) study can be replicated in a laboratory setting; the convenience aspect of the experiment toward the employed approach in this study encompasses contradiction in terms of methodological preferences. However, the findings are still critical to this study on the grounds of establishing the framework for hormone variation and effects analysis.
The previously reviewed studies are significant in terms of conceptual clarity. However, the studies were conducted using animal sample. Applying the concept of thyroid hormone variation on pregnant women requires looking into previous studies that present findings attributed to human conditions. The study conducted by Boas et al. (2009) provides significant findings towards identification of maternal thyroid variation in pregnancy using a longitudinal method. The narrow intra-individual variation in maternal thyroid function was measured by analyzing the statistical data obtained laboratory results of 979 blood samples from 132 women (Boas et al., 2009, p. 905). Using a longitudinal design, a predictive model was created to identify each thyroid variable as a primary function for gestational age. The results of the study suggests that intra-individual variation of thyroid function is not associated to maternal BMI levels before pregnancy. Instead, thyroid variation was found to have positive association to serum levels of FT3 and T3 respectively.
The findings also identified influencing factors towards maternal thyroid hormone variation such as smoking, which was found to have significant association to FT4 and T4 changes during pregnancy (Boas et al., 2009, p. 905). This is because smokers have lower serum concentration as compared to non-smoking females. It is apparent that intra-individual factors and lifestyle has a detrimental effect to hormone levels and variations prior and during pregnancy (Burguet et al., 2004). Identifying factors is an important step in determining hormone variation among pregnancy women, which is relevant in this study. In order to identify hormone variation during pregnancy, intra-individual attributes had to be considered because as the findings suggest intra-individual factors do create changes on maternal thyroid hormones. The significance of this finding towards the objectives of this study is the presentation of statistical evidence pointing to the intra-individual variation, which is correlated to maternal thyroid functions.
The results of the Boas et al., (2009) study encompasses a link on the results of the study conducted Benhadi et al. (2009) wherein the TSH (thyroid stimulating hormone) levels in pregnancy associated to maternal risks were described. Risks are identified as miscarriage, fetal or neonatal death that occurs during pregnancy. It is apparent that TSH is vital for the development of fetal brain and the early life of the baby. Whereas, a perceived decline in TSH level among pregnant women poses pregnancy risks according to Benhadi et al. (2009, p. 985). The research was based on the prospective cohort study of pregnant women form the ABCD Study conduced in collaboration with health agencies in Amsterdam (Benhadi et al., 2009, p. 986). The findings from cohort study analysis revealed that the occurrence of fetal death and miscarriage among pregnant women is attributed to pregnancy risks wherein 5% of the 2,476 samples showed indications of TSH concentration lower below 0.34 mU/l (Benhadi et al., 2009, p. 987). This evidence was validated by measuring the TSH and FT4 levels of native Dutch women wherein, the statistical data revealed that lower concentration of TSH is accounted for 1.48% of child loss during pregnancy and 1.11% of new-born death after seven days based on the total sample population (Benhadi et al., 2009, p. 988).
The determined cause of pregnancy risk in relation to low TSH level is the alterations in pituitary-thyroid axis, which is responsible for thyroid-binding globulin and increase in T4 and T3 including serum thyroglobulin (Karakosta et al., 2011, p. 5). The findings and assumptions presented in the reviewed literature contribute to this study in terms of establishing risk factors attributed to thyroid hormone levels. This encompasses evidence on the hormone variation on pregnant women including the consequential effect of hormone variation levels. In the study by Koninger et al. (2013), the anti-mullerian levels were measured during pregnancy and postpartum. The AMH is regarded as an important predictor of ovarian reserve in which variation of such hormone determines pregnancy and postpartum. According to Koninger et al. (2013), the perceived decline or fluctuations in AMH level has an apparent effect on fertility and is dependent of age (p. 5).
Furthermore, the study reveals that AMH level among women without fertility impairment declines as age increases (Koninger et al., 2013, p. 6). It can be assumed from the findings of study postpartum depression is attributed to the AMH fluctuation that occurs during pregnancy. Pregnant female in the age of 27 years and below appears to have the highest AMH concentration at 2.12 ng/ml and significantly increases as gestation progresses to the second and third trimester (Koninger et al., 2013, p. 5). On the other hand, pregnant women at the age of 35 years and above has the lowest AMH level at 0.61 ng/ml and fluctuates during the course of pregnancy (Koninger et al., 2013, p. 5). Due to the low AMH levels after giving birth, physiological and psychological changes occur as manifestations of postpartum and related depressions occur. One of the causes of AMH decline apart from age is the loss of the hormone-producing placenta, which is being expelled from the uterus upon giving birth (Weghofer et al. as cited in Koninger et al., 2013, p. 7). The findings in this study present important insights to other hormones that deliver a unique function during pregnancy. This information contributes to this study in terms of identifying hormone variations during pregnancy and evidence suggesting specific function and the varying factors leading to hormone variation during pregnancy.
Methodology
The research method that was used in this study is a qualitative approach. We used some in-depth analysis of the research methods done in various literatures so as to come up with evidenced-based results. A review of a literature was done in order to reveal the important results such as the concentration of the oestradiol and progesterone while in the process of pregnancy. Obtaining this result became possible due to the presentation of data that presents the accurate level of progesterone in the peripheral plasma.
Another analysis was done with respect to the research conducted by Dowling et al. (2000). The results of such research were compared to the first research done by Nasar and Rahman (2006) in which significant data were presented along with the overall results of the study. Based on the qualitative analysis, experimental method was done in using a rat that portrays limited or small-scale experiments of the subject. The method of research in this literature shows a confined study between the reactions of the fetal rat prior to the change of hormones from the thyroid.
Based on the research conducted using rats as subjects, brain development significantly reacted while the thyroid hormone is changing. Furthermore, the manipulation effects of the maternal thyroid hormone on gene expression in the fetus’ brain were measured so as to evaluate the potential effects of thyroid hormone towards the brain. This research was done to demonstrate that thyroid hormone affects the gene expression in the fetal brain. Additionally, since the manipulation of the thyroid status of rats prior to the fetal thyroid function, the results showed that thyroid hormone specifically affects the fetal gene expression and its brain function.
Findings
A change in thyroid related hormones has been studied in which most of the respondents were woman living in an urban area that has an iodine deficiency. Shan Elahi and Zaib Hussain (2013) claim that most of the respondents experienced abortion or miscarriage when they were previously pregnant. Within 280 participants, 15-25% of them were having a lower thyroidal hormone during their pregnancy. Additionally, the results show that a pregnant woman’s FT4 decreased by 17.9& during the first trimester of their pregnancy. There was a significant increase happened during the second trimester, as it reached a 28.2% and went down on the third trimester by 26.9%. Looking at the research results, it is evident that hormonal change in the thyroid gland may increase and decrease during the 9-moth period of pregnancy. This research aimed to make documentation about the relative changes in thyroid hormones to non-pregnant women as well as the pregnant women who live in the same iodine-deficient area.
A normal thyroid function is very important during pregnancy, so that the fetus will develop normally and healthy. A clinical study that pertains to the variation of thyroid function during pregnancy between women was conducted to see if thyroid hormone changes are related to the gender of the fetus. Based on the results, there were evident hormonal change during the pregnancy, but none of the changes were related to the child’s maternal parity (Boas et al., 2009). The longitudinal research design was used in this study so as to develop a prognostic model for each of the thyroid variables as a role of gestational age that includes significant covariates in the related models.
Discussion
As we look at the literatures, it may be safe to presume that the pregnant woman’s hormonal change is just as normal. However, there are factors that may not be discussed in-focus by these literatures such as the nutritional importance of the pregnant woman. Similarly to what Mary Picciano (2014) claimed that the reaction of the hormone goes along with the secretion of milk from the mammary gland. As such, there is a recommended energy intake for pregnant women, which was based on the quantitative data than just the usual recommendations during the pregnancy. In relation, the nutritional recommendations for pregnant women may change, as the nutrient levels in the tissues as well as the fluids that are available for evaluation are normally being altered by hormone-induced changes including change in the volume of plasma and the changes in renal function (Picciano, 2014 p.1998).
As mentioned, the changes in hormone also affect the secretion of milk from the mammary gland. Additionally, the hormonal change during pregnancy also affects the growth of the mammary gland. Roberto Ceriani (1974) suggests that due to the change of hormones, the mammary gland is being affected and goes to several processes. First, the mammogenesis that involves cell functions, which lead to the total increase of the mass of the mammary gland. The second process is the lactogenesis that involves the creation, within the mammary gland’s epithelial cells. This is responsible for the production of milk. The third process is the milk ejection. It is the process of milk extrusion that was stored in the lumina of alveoli (Ceriani, 1974 p.93). The processes of milk production during and after pregnancy happen all because of the hormonal change that normally takes place during these period. It was evident in the method of study that pregnancy is the period when many changes happen to a woman in terms of physiological as well as the body’s chemistry.
Conclusion
Pregnancy is an event that must be appreciated in every woman’s life. Along with it are changes with their body especially with their hormones that makes it somehow challenging on the woman’s part. These are the adjustments that affect the physiological aspect of their body such as the hormonal changes. Based on the literatures, these changes play some important roles in the development of the fetus inside the womb. Thus, it responsible for the neonatal development until the baby is born. These hormones are also responsible for the baby’s brain functions that could serve as the foundation of good brain functions while the baby is growing up. This claim was evidently discussed in the literature in which the hormonal change was also regarded as one of the factors that affects the fetus’ brain development. We also learned that progesterone as well as the estrogen is the major pregnancy hormones. As we look at the discussions in the literature, we also learned that a pregnant woman produces more estrogen than a non-pregnant one. In fact, it is even more than the entire life of a non-pregnant woman. Generally, the changes in hormone may not just affect the physiological aspect of the body internally, but it may also affect other parts of the body such as the hair and nail growth. Therefore, it may be safe to conclude that pregnancy could make dramatic changes in a woman’s life that make it quite challenging, but a memorable experience.
References
Benhadi, N., Wiersinga, W. M., Reitsma, J. B., Vrijkotte, T. G., & Bonsel, G. J. (2009). Higher maternal TSH levels in pregnancy are associated with increased risk for miscarriage, fetal or neonatal death. European Journal of Endocrinology, 160, 985-991.
Boas, M., Forman, J. L., Juul, A., Rasmussen, U. F., Skakkebak, N. E., Hilsted, L., . . . Chellakooty, M. (2009). Narrow intra-individual variation of maternal thyroid function in pregnancy based on a longitudinal study on 132 women. European Journal of Endocrinology, 161, 903-910.
Burguet, A., Kaminski, M., Abraham, L., Schaal, J., Cambonie, G., Fresson, J., . . . Grandjean, H. (2004). The complex relationship between smoking in pregnancy and very preterm delivery. Results of the Epipage study. National Institute of Health,111(3), 258-265. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/14961888
Ceriani, R. L. (1974). Hormones and other factors controlling growth in in the mammary gland: a Review. The Journal of Investigative Dermatology, 63, 93-108.
Dowling, A., Martz, G., Leonard, J., & Zoeller, R. T. (2000). Acute Changes in Maternal Thyroid Hormone Induce Rapid and Transient Changes in Gene Expression in Fetal Rat Brain. The Journal of Neuroscience, 20(6), 2255-2265.
Elahi, S., & Hussain, Z. (2013). A Longitudinal Study of Changes in Thyroid Related Hormones among Pregnant Women Residing in an Iodine Deficient Urban Area.ISRN Endocrinology, 2013, 2-6.
Hormonal and Metabolic Factors Associated With Variations in Insulin Sensitivity in Human Pregnancy. (n.d.). Diabetes Care, 33(2), 356-360.
Hormonal Changes in the Uterus During Pregnancy− Lessons from the Ewe: A Review. (n.d.). School of Agriculture and Rural Development, 4(1), 1-7.
Karakosta, P., Chatzi, L., Bagkeris, E., Daraki, V., Alegakis, D., Castanas, E., . . . Koverginas, M. (2011). First- and Second-Trimester Reference Intervals for Thyroid Hormones during Pregnancy in “Rhea” Mother-Child Cohort, Crete, Greece. Journal of Thyroid Research, 2011, 1-12.
Koninger, A., Kauth, A., Schmidt, B., Schmidt, M., Yerlikaya, G., Bauer, S., . . . Kimming, R. (2013). Anti-Mullerian-hormone levels during pregnancy and postpartum. Reproductive Biology and Endocrinology, 11(60), 2-9.
Pregnancy and Lactation: Physiological Adjustments, Nutritional Requirements and the Role of Dietary Supplements. (n.d.). The Journal of Nutrition, 1997-2002.
