Causes of Perimenopause Bleeding and Association with Thyroid Dysfunction: A Cross-Sectional Study

& Objective: Perimenopause period is the transitional period 2-8 years before and one year after the last menstrual period. The most common complaint in this period includes abnormal uterine bleeding; the cause may be structural and non - structural, thyroid hormone known to affect reproductive biology. This study was conducted with aim to evaluate the correlation between thyroid disorder and different causes of abnormal uterine bleeding in perimenopause women.

& Methods: This cross-sectional study was conducted in Iraq \Babylon province from September 2023 to April 2025. The sample population were 49 women aged 40 -51years old who complain from abnormal uterine bleeding. TFT, CBC; transvaginal ultrasound and endometrial biopsy was performed for the patients. Data were analyzed using SPSS software (version 26). P≤ 0.05 was considered statistically significant.

The mean age of participants was 44 years old, with 53.1% (26 women) between 40 and 45, 31(63.3%) multiparous, 38(77.6%) euthyroid, 1(2%) hyperthyroid, and 10(20.4%) subclinical hypothyroid. There was a significant relationship between thyroid function and irregular bleeding ( P<0.05). Among women, 19(38.8%) had menorrhagia, 16(32.7%) poly menorrhoea , 10(20.5%) intermittent bleeding, and 4(8.1%) oligo menorrhoea. AUB was caused by dysfunctional uterine bleeding in 24(49%), endometrial hyperplasia (with or without atypia) in 9(18.4%), adenomyosis in 6(12.2%), fibroid in 5(10.2%), and ovarian cyst in 1(2%). Thyroid function did not alter abnormal uterine haemorrhage causes.

Most women presented with menorrhagia and poly menorrhea between the age 40-45 years with dysfunctional uterine bleeding being the most common cause, and there was strong association between thyroid dysfunction and abnormal uterine bleeding.

Perimenopause, Bleeding, Thyroid, Dysfunction Received: 2025/07/11 Accepted: 2025/09/07 Published Online: 07 Apr. 2026 Corresponding Information: Milal Muhammad Al-Jeborry, College of Medicine, University of Babylon, Babylon, Iraq Email: [email protected] Copyright © 2025, This is an original open -access article distributed under the terms of the Creative Commons Attribution-noncommercial 4.0 International License which permits copy and redistribution of the material just in noncommercial usages with proper citation . 1. Introduction Perimenopause is a transitional phase that typically spans 2 to 8 years before the final menstrual period and extends to one year after it. During this period, women often experience Abnormal Uterine Bleeding (AUB), which may be either physiological or pathological in origin. Such bleeding can significantly impact a woman’s quality of life and provoke considerable anxiety. In certain cases, these abnormalities may indicate serious conditions such as endometrial hyperplasia or even endometrial cancer (1,2). AUB is defined as any change in the regularity, duration, frequency, or volume of menstrual bleeding, affecting approximately 50% of perimenopause women (3). A normal menstrual cycle is characterized by a frequency of 24 to 38 days, a duration of 4 to 8 days, and a total blood loss ranging from 5 to 80 ml per cycle. When these parameters are disrupted, various underlying causes must be considered. The most frequent cause is bleeding of endometrial origin due to hormonal fluctuations without any identifiable organic pathology. However, organic causes may include benign pelvic conditions such as fibroids, adenomyosis, cervic al or endometrial polyps, as well as infections, trauma, iatrogenic factors (e.g., hormone replacement therapy, contraceptive use, or anticoagulants), malignancies of the cervix, endometrium, or ovaries, and systemic illnesses like hypertension, diabetes mellitus, and thyroid disorders (4). Among systemic disorders, thyroid dysfunction - both hypothyroidism and hyperthyroidism -accounts for approximately 30% to 40% of AUB cases (5). Thyroid hormones play a critical role in regulating the menstrual cycle. Thyroid-Stimulating Hormone (TSH) shares a common beta subunit with both Follicle- Banan Natiq Turkey, et al. 436 Volume 11, May 2026 Journal of Obstetrics, Gynecology and Cancer Research Stimulating Hormone (FSH) and Luteinizing Hormone (LH), and thyroid hormone receptors are also found in the ovaries (6). The mechanisms through which thyroid disorders lead to AUB include altered TSH response, increased prolactin levels, changes in LH response, effects on the peripheral conversion of androgens to estrogens, alterations in Sex Hormone -Binding Globulin (SHBG) levels, and disruptions in the coagulation cascade -specifically reductions in factors VII, VIII, IX, and XI. Hypothyroidism, in particu lar, reduces SHBG production and alters estrogen metabolism, thereby disrupting pituitary feedback mechanisms (7,3). Hyperthyroidism is associated with an increased gonadotropin response to Gonadotropin- Releasing Hormone (GnRH) and elevated baseline gonadotropin levels. Although hypomenorrhea in hyperthyroid women may be attributed to changes in coagulation factor VII, ovulation often still occurs, as confirmed by endometrial biopsy findings (8). Hyperprolactinemia, another endocrine disturbance, interferes with follicular maturation and corpus luteum function. It inhibits the hypothalamic -pituitary axis by suppressing the pulsatile release of GnRH, resulting in inadequate LH and FSH secretion, and ultimately leading to anovulation (7). The present study was conducted with aim to investigate the relationship between thyroid dysfunction and abnormal uterine bleeding in perimenopausal women. 2. Materials and Methods This cross-sectional study was conducted in Iraq/ Babylon province from September 2023 to April 2025. The study population were 49 women between 40 -51 years old who complain from abnormal uterine bleeding. The exclusion criteria were bleeding disorder, pregnancy, Diabetes Mellitus ( DM), hypertension, IUCD insertion, use hormonal replacement therapy, cervical pathology. In patients with thyroidectomy, the detailed history including age, parity, bleeding pattern, past medical & surgical history, and drug used was obtained. BMI w as calculated as weight in kg divided on the height in square meters. Abdominal and pelvic examination was done. TFT and CBC were measured; then transvaginal ultrasound and endometrial biopsy was performed. FIGO (9) defines heavy menstrual bleeding as more than 80 ml; however, our definition includes bleeding that disrupts a woman's physical, emotional, and social well-being, either independently or in conjunction with other symptoms, as per the NICE guideline (10). Abnormal uterine bleeding is defined as a ny bleeding that is heavier, more frequent, or lasts longer than what is considered normal for the individual.

Value Serum T4: 60-120 ng/mL Serum T3-0.8-16 ng/ml Serum TSH-0.5-5 mU/ml Then, a transvaginal ultrasound was done to determine the uterine and ovarian pathology. The patient, whose endometrial thickness exceeded 10.5 mm, underwent an endometrial biopsy for histopathological study (11). Data were analyzed using the Statistical Package for the Social Sciences (SPSS) (version 26). Descriptive statistics were expressed as frequencies and percentages. Chi-square tests and t -tests were used to show the association between the variables. P≤0.05 was considered as statistically significant. 3. Results A total of 49 priemenopausal women with complaint from abnormal uterine bleeding were included in this study. The mean age of participants was 44 years old (minimum 40 years and maximum 50 years). Moreover, 26 women (53.1%) aged between 40 -45 years and 46. 9% between 46 -52 years old. Among these women, 5(10.2%) were nulliparous, 4 had one child (8.2%), 9(18.4%) had 2 children, and 31(63.3%) were multiparous (Table 1). Regarding the endometrial thickness, in 16 women (32.7%) was more than 10.5 mm and endometrial biopsy was done, and in 33(67.3%) was less than 10.5 mm. Table 2 shows that thyroid status of women. There was 38 women (77.6%) with euthyroidism, 1(2%) hyperthyroidism, and 10(20.4%) subclinical hypothyroidisms. Table 3 shows the most common symptoms of women was menorrhagia in 19(38.8%), poly menorrhea in 16(32.7%), intermittent bleeding in 10(20.5%) and the least presentation was oligo menorrhea in 4(8.1%). The duration of AUB in most patients (40.8%) was less than 6, months and between 6 -12 months in 16 (32.7%), and more than 12 months in 13(26.5%) (Table 4). Table 5 shows that there was statistically significant correlation between the thyroid status and pattern of abnormal bleeding (P=0.006). Table 6 shows that there was no significant correlation between bleeding pattern and endometrial thickness (P=0.514). Table 7 shows that the most common cause of AUB was dysfunctional uterine bleeding in 24 (49%), then endometrial hyperplasia (with or without atypia) in 9 (18.4%), and adenomyosis in 6 (12.2%). Table 8 shows that there was no significant correlation between the causes of abnormal uterine bleeding and thyroid status (P=0.532). 437 Perimenopause Bleeding and Association Volume 11, May 2026 Journal of Obstetrics, Gynecology and Cancer Research Table 1. Parity of women with AUB Parity No. Percentage (%) Nulliparous 5 10.2 Para 1 4 8.2 Para 2 9 18.4 Para 3 and more 31 63.3 Total 49 100.0 Table 2. Thyroid status among perimenopousal women Thyroid status No. Percent (%) Euthyroidism 38 77.6 Hyperthyroidism 1 2.0 Subclinical hypothyroidism 10 20.4 Total 49 100.0 Table 3. Distribution of symptoms among women Bleeding pattern NO. Percent (%) Poly menorrhea 16 32.7 Menorrhagia 19 38.8 Oligo menorrhea 4 8.1 Intermittent bleeding 10 20.4 Total 44 100.0 Table 4. Duration of symptoms of patients with AUB Duration No. of cases Percentage % 1-6 months 20 40.8 6-12 months 16 32.7 More than 12 months 13 26.5 Total 44 100.0 Table 5. Association between thyroid status and different forms of abnormal uterine bleeding Bleeding pattern Thyroid status Total Euthyroidisim Hyperthyroidism Subclinical hypothyroidism Intermittent bleeding 8(16.3%) 1(2%) 1(2%) 10(20.4%) Menorrhagia 10(20.4%) 0 9(18.4) 19(38.8) Oligo menorrhea 4(8.2%) 0 0 4(8.2%) Polymenorrhea 16(32.7%) 0 0 16(32.7%) Total 38(77.6%) 1(2%) 10(20.4%) 49(100%) P-value 0.006 Banan Natiq Turkey, et al. 438 Volume 11, May 2026 Journal of Obstetrics, Gynecology and Cancer Research Table 6. Association between bleeding pattern and endometrial thickness Endometrial thickness Bleeding pattern Total Intermittent bleeding Menorrhagi a Oligo menorrhea Polymenorrh ea =10.5mm 3(6-1%) 7(14.3%) 0 6(12.2%) 16 Total 10(20.4%) 19(38.8%) 4(8.2%) 16(32.7%) 49(100%) P-value 0.5 Table 7. Distribution of causes of AUB among women Cause of bleeding No. Percent (%) Adenomyosis 6 12.2 Adenomyosis + fibroid 1 2.0 Endometrial hyperplasia (with and without atypia ) 9 18.4 Endometrial hyperplasia + ovarian cyst 1 2.0 Fibroid 5 10.2 Dysfunctional uterine bleeding 24 49 Ovarian cyst 1 2.0 Polyp 2 4.1 Total 49 100.0 Table 8. Association between causes of AUB and thyroid status Causes of AUB Thyroid status Total Euthyroidisim Hyperthyroidism Subclinical hypothyroidism Adenomyosis No.(%) 5(10.2%) 0(0.0%) 1(2.0%) 6(12.2%) Adenomyosis + fibroid No.(%) 1(2.0%) 0(0.0%) 0(0.0%) 1(2.0%) Endometrial hyperplasia + ovarian cyst No.(%) 1(2.0%) 0(0.0%) 0(0.0%) 1(2.0%) Endometrial hyperplasia No.(%) 8(16.3%) 0(0.0%) 1(2.0%) 9(18.4%) Fibroid No.(%) 2(4.1%) 1(2.0%) 2(4.1%) 5(10.2%) Dysfunctional uterine bleeding No.(%) 18(36.7%) 0(0.0%) 6(12.2%) 24(49.0%) Ovarian cyst No.(%) 1(2.0%) 0(0.0%) 0(0.0%) 1(2.0%) Polyp No.(%) 2(4.1%) 0(0.0%) 0(0.0%) 2(4.1%) Total No.(%) 38(77.6%) 1(2.0%) 10(20.4%) 49(100.0%) P-value 0.5 439 Perimenopause Bleeding and Association Volume 11, May 2026 Journal of Obstetrics, Gynecology and Cancer Research 4. Discussion Abnormal Uterine Bleeding (AUB) is a common complaint among women in the perimenopausal period, particularly those aged between 40 and 45 years. This result aligns with the findings of Meena et al., (4) and Sahu HD et al. , (12), who reported similar age distributions, with a mean age of 44 years. In our study, most patients (63.3%) were Para 3 or more, a finding consistent with Sahu HD et al. , (12), though higher than that reported by Byna et al. , (13). Menorrhagia emerged as the most frequent clinical presentation among perimenopausal women, accounting for 38.8% of cases in the present study, which corresponds with the findings of Some studies (4,6,12,14). Polymenorrhagia was the next most common presentation (32.7%) of our study, which agrees with the results of Begum et al., (15). Regarding thyroid function, most women in our study were euthyroid (77.6%), followed by subclinical hypothyroid cases (20.4%). This distribution is comparable to the findings by Byna et al. , (13), who reported 64.5% euthyroid, 21.8% hypothyroid, and 12.72% hyperthyroid patients, as well as Sharma et al., (16), who reported 64% with euthyroid and 22% hypothyroid. Our study identified only 2% of patients with hyperthyroidism, slightly lower than that (4%) reported by Sahu et al. , (12), which may be attributed to the smaller sample size and regional variation in our study population. In terms of healthcare -seeking behavior, 40.8% of women in our study presented for medical evaluation within six months of symptom onset, like the findings of Meena et al. , (4). Importantly, our study demonstrated a significant correlation between thyroid dysfunction and AUB. Among those with subclinical hypothyroidism, 20.4% presented with menorrhagia and polymenorrhagia. This pattern is consistent with that reported by Meena et al., (4), who found that 20% of patients with AUB had subclinical hypothyroidism. Meanwhile, 77.6% of euthyroid women in our study experienced AUB, most commonly in the form of polymenorrhea, a slightly higher proportion than that (64.5%) reported by Byna et al., (13). Dysfunctional Uterine Bleeding (DUB) was identified as the most prevalent underlying cause of AUB in our cohort, affecting 49% of patients. Endometrial hyperplasia (with or without atypia) was present at 18%, and adenomyosis in 12.2%. These findings differ from those of Sahu et al. , (12), who reported DUB in only 12% of cases and a higher incidence of adenomyosis (33.6%). This variation may stem from differences in the age range and demographics of the populations studied. While Subedi et al. , (17) found hypothyroidism as the commonly associated with DUB, our results showed that 36.7% of women with DUB were euthyroid, and no significant association was found between specific causes of AUB and thyroid status. A key limitation of our study is that it was conducted in a single center with a relatively small sample size, despite covering an extended study period. This may limit the generalizability of the findings and underscores the need for larger, multicenter s tudies to further clarify the relationship between thyroid dysfunction and abnormal uterine bleeding. 5. Conclusion Most common presentation of AUB was menorrhagia and polymenorrhea in women during perimenopause period commonly aged between 40 -45 years old with dysfunctional uterine bleeding being most common cause fallowed by endometrial hyperplasia (with or without at ypia). Thyroid status was correlated with AUB and subclinical hypothyroidism being the most common form of thyroid dysfunction. 6. Declarations Acknowledgments The authors would like to thank Babylon college of medicine/university of Baghdad for supporting this research. Ethical Considerations This research has received ethical approval from Al- kindy College of medicine/university of Baghdad with the number 322 in 25-2-2025. Authors' Contributions BT designed the idea of the study, planned the experiments, collected and analyzed the data, and wrote the first draft of the manuscript. MM finished analyzing the data, reading the manuscript, and helped plan the study. HH read and made changes to the manuscript. All authors read and approved the final version of the article. Conflict of Interest The authors declared no conflict of interest. Fund or Financial Support The authors declared no fund. Banan Natiq Turkey, et al. 440 Volume 11, May 2026 Journal of Obstetrics, Gynecology and Cancer Research 1. Dreisler E, Frandsen CS, Ulrich L. Perimenopausal abnormal uterine bleeding. Maturitas. 2024 ;184:107944. [doi:10.1016/j.maturitas.2024.107944] 2. Hameed Z, Abdulrazzaq M, Mahood A, Salem K, Hassooni Z, Abbas H. 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441 Perimenopause Bleeding and Association Volume 11, May 2026 Journal of Obstetrics, Gynecology and Cancer Research How to Cite This Article: Natiq Turkey B, Al-Jeborry M.M, Khudheir Hussein H. Causes of Perimenopause Bleeding and Association with Thyroid Dysfunction: A Cross-Sectional Study. J Obstet Gynecol Cancer Res. 2026;11(5):435-441. Download citation: RIS | EndNote | Mendeley |BibTeX |