Journal of the Scientific Society

ORIGINAL ARTICLE
Year
: 2021  |  Volume : 48  |  Issue : 1  |  Page : 13--16

Study of thyroid profile and prolactin levels in female infertility patients: An institutional analysis


Sonia Kundu1, Sudhamani S Rao2, Kritika Singh2, Rajiv Rao2,  
1 Department of Pathology, Civil Hospital, Panipat, Haryana, India
2 Department of Pathology, Padmashree Dr. D. Y. Patil Medical College, Navi Mumbai, Maharashtra, India

Correspondence Address:
Dr. Sudhamani S Rao
Department of Pathology, Pad Dr. D. Y. Patil Medical College, Nerul, Navi Mumbai, Maharashtra
India

Abstract

Introduction: Thyroid as an endocrine organ along with prolactin hormone plays a significant role in the fecundity of the couple. Disorders in these hormones may cause menstrual abnormalities and anovulation, leading to infertility. Its dysfunction is not uncommon and is often reversible or preventable with early detection and treatment. This study was undertaken to study the occurrence of thyroid hormone dysfunction and hyperprolactinemia in infertile women. Materials and Methods: In this study, we studied the thyroid profile and prolactin levels in 100 infertile women who visited the obstetrics and gynecology department or in vitro fertilization center of a tertiary care hospital. The frequency of hypo- and hyperthyroidism along with hyperprolactinemia was studied, and the association between thyroid dysfunction and levels of serum prolactin was analyzed. Results: The majority of the infertile women were euthyroid. Thyroid dysfunction was noted in 27% of infertile women, with 17% showing hyperthyroidism and 10% showing hypothyroidism. Hyperprolactinemia was observed in 9% of infertile females. Hypothyroidism was found to be positively associated with hyperprolactinemia. Conclusion: Blood examination for thyroid hormone and prolactin should be kept in consideration as important routine workup in female infertility patients so that patients can be appropriately managed.



How to cite this article:
Kundu S, Rao SS, Singh K, Rao R. Study of thyroid profile and prolactin levels in female infertility patients: An institutional analysis.J Sci Soc 2021;48:13-16


How to cite this URL:
Kundu S, Rao SS, Singh K, Rao R. Study of thyroid profile and prolactin levels in female infertility patients: An institutional analysis. J Sci Soc [serial online] 2021 [cited 2021 Jun 17 ];48:13-16
Available from: https://www.jscisociety.com/text.asp?2021/48/1/13/315457


Full Text



 Introduction



Infertility, defined as the failure to conceive after 1 year of regular intercourse without contraception, is a worldwide problem affecting people of all communities. It is estimated that, globally, 60–80 million couples suffer from infertility every year, of which between 15 and 20 million are in India alone. Considering the current population statistics of India, this extrapolates to a humongous number.[1]

While primary infertility is infertility in a couple who have never had a child, secondary infertility is an inability to conceive following a previous pregnancy.

The causes of infertility can be due to female factors, male factors, combined factors, or unexplained. Under female factors, the important causes of infertility include hormonal conditions such as thyroid problems, diabetes, hyperprolactinemia, and polycystic ovary syndrome.[2]

Thyroid dysfunction is prevalent in the female population and is known to affect reproductive function and even pregnancy. Thyroid hormones (triiodothyronine T3 and tetraiodothyronine T4) are responsible for the normal growth, sexual development, and reproductive physiology. Undiagnosed and untreated thyroid disease can be a cause for infertility as well as subfertility.[3] Another hormone that plays an important role in female infertility is prolactin. Hyperprolactinemia causes infertility by primarily interfering with ovulation. Furthermore, increased levels of thyroid-stimulating hormone (TSH) seen in hypothyroidism are often associated with increased prolactin levels, which leads to a delay in luteinizing hormone (LH) response and abnormal ovulation.

Many studies highlight thyroid dysfunction and hyperprolactinemia as common endocrine abnormalities in females, and considering the importance of these hormones in infertility, the present study aims at studying the occurrence of thyroid hormonal disorder and increased prolactin levels in female infertility cases in our institute.

 Materials and Methods



This was a prospective study conducted at a tertiary care postgraduate teaching hospital. All female infertility cases, both primary and secondary, who visited the hospital over a period of 2 years from July 2013 to July 2015 were included in the study. Informed and written consent of all participants was taken, and the study was approved by the institutional ethical committee.

Relevant clinical history including menstrual history, family history, duration of infertility, and obstetrics history was recorded.

All female infertility patients coming to obstetrics and gynecology department or in vitro fertilization center of the same hospital and sending their blood sample to the laboratory medicine department were included in the study irrespective of age, duration of infertility, and semen analysis findings of husband. Those patients in which samples were received for evaluation of other hormones were excluded from the study.

Thyroid profile analysis and serum prolactin levels were measured by a fully automated chemiluminescence immunoassay analyzer (Snibe MAGLUMI 1000). The normal reference range for various hormones tested was serum T3: 0.7–2.04 ng/dl, serum T4: 5.5–11 ug/dl, serum TSH: 0.4–4.2 uIU/ml, and serum prolactin: 2.8–19.2 ng/ml. These values were as per the instructions of the kit supplier.

 Results



The present study was conducted on a total of 100 female patients of infertility. Out of the 100 cases studied, 74 (74%) cases were of primary infertility and 26 (26%) cases were of secondary infertility. Included females had an age range of 18–42 years. The maximum number of cases (53%) belonged to 28–32 years of age group, followed by 23% of cases in the age group of 23–27 years.

It was observed that the total duration of infertility in the present study group ranged from 2 to 13 years and 37% of the cases had infertility for 5–7 years [Table 1]. Abnormal menstrual pattern was seen in 48% of cases. Most had complaints of irregular menses seen in 32% of cases, followed by oligomenorrhea in 7% of cases, polymenorrhea in 5% of cases, and menorrhagia in 4% of cases [Table 2].{Table 1}{Table 2}

In the present study, euthyroidism was the most common and was seen in 73 (73%) cases. Thyroid dysfunction was seen in the remaining 27 (27%) cases comprising hyperthyroidism and hypothyroidism in 17 (17%) and 10 (10%) cases, respectively [Table 3]. On studying serum prolactin levels, it was observed that most females had normal levels of hormone, and hyperprolactinemia was seen in 8 (8%) cases [Table 3]. Of the ten cases of hypothyroidism, six had increased prolactin levels and six out of nine hyperprolactinemic women had hypothyroidism [Table 4]. Chi-square analysis showed a significant association between prolactin level and thyroid status (P < 0.001) with a phi coefficient of 0.594 indicating a strong positive relationship between the two parameters.{Table 3}{Table 4}

 Discussion



Thyroid disorders including overproduction of thyroid hormones (hyperthyroidism) and underproduction of the hormones (hypothyroidism) can cause significant reproductive problems in women. Human oocytes and granulosa cells express thyroid receptors, and thus abnormal hormone production is associated with delayed onset of puberty, menstrual disorders, anovulatory cycles, infertility, and early pregnancy loss.[3]

Prolactin, a peptide hormone produced by the anterior pituitary gland, is primarily associated with breast development during pregnancy and milk production during lactation. Increased blood levels decrease the secretion of gonadotropin-releasing hormone in the hypothalamus, thereby decreasing the secretion of LH and follicle-stimulating hormone in the pituitary gland which in turn leads to decreased production of estrogen and progesterone by the ovaries. Decreased hormone production in the ovaries leads to disruption of the normal follicular development causing atresia of the dominant follicle, which interferes with ovulation. Hyperprolactinemia could be physiological like in pregnancy, pathological (e.g., hypothalamic-pituitary disease), or idiopathic in origin.[4]

There is also a close interrelation between hypothyroidism and hyperprolactinemia. Increased thyrotropin-releasing hormone seen in hypothyroidism stimulates both thyrotrophs and lactotrophs, thus increasing the level of both TSH and prolactin. Morphological changes observed in the follicles in hypothyroidism can be a consequence of higher prolactin production.[5] Adequate thyroid supplementation can restore prolactin levels to optimal range and normalize ovulatory function.

Our study consisted of 100 infertile women with a maximum number of women in the age group of 28–32 years followed by 23–27 years. Such findings have also been reported by Mehra et al. (n = 100) with most infertile women in the age group of 28–32 years and Saxena et al. (n = 50) as 22–30 years.[6],[7] Biradar SM et al. (n = 50) also reported most infertile women in the age group of 24–28 years.[8] Just like in our study, in all of the above studies, most females had primary infertility. In our study, the maximum duration of infertility ranged from 5 to 7 years. Most infertile women in the study by Mehra et al. had a duration of infertility of <3 years, while Biradar SM et al. have reported most cases with an average duration of infertility of <5 years. The duration of infertility in both these studies was found to be lesser in comparison to our study.[6],[8] In our study, 48% of the infertile women complained of menstrual disturbances. In other studies, a higher number of cases with menstrual abnormalities were reported with Binita et al. (n = 160) as 61.2%, Mehra et al. as 57%, and Sharma et al. (n = 100) as 56%.[6],[9],[10]

This study was directed to evaluate how many infertile females have an imbalance in thyroid and prolactin hormone levels. In the present study, out of 100 cases studied, abnormal thyroid hormone levels were seen in 24% of infertile females with 14% showing hyperthyroidism and 10% showing hypothyroidism. This is comparable to the prevalence of thyroid dysfunction found in infertile women as 33.3% in a study by Rahman et al. (n = 30) and 25.5% by Keerthanaa and Hiremath (n = 200).[11],[12] Majority of the patients in our study as well as most other studies were in a euthyroid state, which may be attributable to other causes of infertility.

In our study, hypothyroidism was seen in 10 (10%) of female infertility cases. In a study conducted by Verma et al. on 394 infertile women, the frequency of hypothyroidism was higher being 23.9%.[13] Another work published by Keerthanaa and Hiremath (n = 200) reported 23.5% of infertile females were hypothyroid.[12] This is higher in comparison to our results. This discordance can be probably due to the smaller sample size of our study. Few other studies also reported a higher number of female infertile patients with hypothyroidism with Mehra et al. (n = 100) observing hypothyroidism in 22% of cases, whereas Priya (n = 95), Sharma et al. (n = 100), and Hivre MD et al. (n = 50) found occurrence of 53.7%, 17%, and 20%, respectively.[5],[6],[10],[14] Our study was in agreement with regard to having a similar number of hypothyroid infertile patients as reported by Goswami et al. (n = 160), Rijal et al. (n = 735), Rahman et al. (n = 30), and Biradar SM et al. (n = 50) where the occurrence of hypothyroidism was found to be 8%, 7.6%, 6.7%, and 6%, respectively.[8],[9],[11],[15]

Hyperthyroidism was seen in 14% of our cases. Binita et al. and Mehra et al. reported lower prevalence as 5% and 1% cases of hyperthyroidism, respectively, while a study by Hivre MD et al. and Biradar SM et al. reported hyperthyroidism in 34% and 26% of infertile women, respectively.[6],[8],[9],[14] This was more in comparison to our study.

Vidhyalakshmi did a prospective study that was undertaken to determine the frequency of hyperprolactinemia in a group of infertile women. Among 100 infertile patients, 10 (10%) had elevated levels of serum prolactin.[16] These findings correlate to our study, where 9% showed increased prolactin. Other studies showed a higher prevalence of infertility cases showing elevated prolactin levels with Priya et al. showing 53.7% of cases, Sharma et al. and Binita et al. 41% cases, Verma et al. 37% cases, Keerthanaa et al. 31% cases, Mehra et al. 26% cases, and Verma et al. reporting 18.3% of cases.[5],[6],[9],[10],[12],[13],[17]

Just like in our study, Mehra et al. also observed a highly significant association between prolactin levels and thyroid status among infertile women.[6] Case–control study done by Hivre MD et al. and Binita et al. reported that the infertile women with hypothyroidism had significantly higher prolactin levels in comparison to the control group.[9],[14] Similarly, Saxena et al. (n = 50) also noted a strong positive correlation between serum TSH and prolactin in infertile women (P < 0.05).[7]

 Conclusion



It is imperative to check the thyroid status and prolactin levels in all infertile females as a part of their diagnostic protocol. Hypothyroidism combined with or without hyperprolactinemia is proved to be one of the important causes of female infertility and therefore should be ruled out before other therapeutic options.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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