Uterus & Periods: How this small organ can impact menstrual health?

Many factors affect our menstrual health. These factors can be broadly divided into two categories, internal and external. 

Most of the time, periods influenced by internal factors are due to hormonal imbalances. 

But abnormalities of the uterus may also affect periods and overall reproductive health.

Basic Anatomy of the Uterus 

The frontal section of the uterus depicts it as a pear-shaped organ. Imagine it as an upside-down pear. The narrowest part is known as the cervix, opposite to the cervix is the fundus, and between them is the body of the uterus. The body of the uterus consists of the uterine cavity surrounded by the 3-layered uterine wall. 

The outermost layer of the uterine wall is the endometrium. This is the layer that in response to hormones, sheds during the menstrual cycle. The middle layer is the myometrium, the smooth muscle layer. And the innermost layer is known as the perimetrium. 

The uterus measures 7.5 cm in length, 5 cm in width, and is 2.5 cm thick. It weighs between 30-40 grams. Somewhat small for its tremendous role in a woman’s reproductive health. 

Uterine Anomalies

These are congenital malformations of the uterus that disrupt the normal shape of the uterus. They typically do not exhibit any symptoms and are incidentally discovered during the evaluation of pregnancy loss or infertility. Some women with uterine anomalies may experience severe pain during their periods. 

Uterine anomalies increase the risk of miscarriages, preterm delivery, or infertility. 

● Septate​: a fibrous-muscular membrane that runs down the middle of the uterus dividing it into two cavities.

● Arcuate: can be considered a normal variant of the uterus. It is a small indentation that extends from the endometrium at the fundus, into the uterine cavity. The indentation is generally less than 1cm. 

● Unicornuate​: only one half of the uterine cavity develops.The most common type of unicornuate uterus is associated with painful heavy periods (which may be due to endometriosis) 

● Bicornuate​: ‘heart-shaped’ uterus. A thick muscular wall runs down the middle of the uterine cavity. A bicornuate uterus can result in heavy painful periods. 

● Didelphys​: is also known as ‘double uterus’ because two halves of the uterine cavity remain separate (two uterine cavities, two cervices). It can be diagnosed on a routine physical examination.

Conditions involving the Uterine Wall

These conditions are more common when compared with uterine anomalies. They exhibit a myriad of symptoms amongst women, ranging from abnormal uterine bleeding to infertility. Abnormal uterine bleeding consists of heavy periods, painful periods, bleeding between cycles, and/or irregular cycles. 

● Uterine fibroids, also known as leiomyomas, are benign tumors that grow within the smooth muscle wall of the uterus. They vary in size and most women do not have any symptoms. 

● Polyps​ are benign outgrowths of the endometrial tissue (consisting of glands and blood vessels) into the uterine cavity. They sometimes cause abnormal uterine bleeding and rarely transform into cancer. 

● Endometriosis​ is a condition in which endometrial tissue grows outside of the uterus. The endometrial cells can be implanted on the ovaries, bladder, bowel (rectum or anus), and the surrounding pelvis. The abnormally located endometrial tissue will respond to hormonal changes and shed during each menstrual cycle. Other than causing painful periods, endometriosis can also cause painful urination, defecation, and intercourse. Prolonged untreated endometriosis can eventually lead to infertility.

● Adenomyosis​ occurs when the endometrial tissue is implanted within the smooth muscle layer (middle layer of the uterine wall) of the uterus. Adenomyosis can co-exist with other gynecological disorders such as endometriosis and/or fibroids. Its symptoms are similar to that of endometriosis. 

● Pelvic Inflammatory Disease (​PID​) is a chronic infection of the upper reproductive tract (involving the uterus, fallopian tubes, and ovaries). Many organisms are implicated in this infection, but most commonly involved are Chlamydia​ and Gonorrhoea. Delayed diagnosis and inadequate treatment of PID will result in chronic inflammation, which ultimately leads to scarring, fibrosis, and formation of adhesions within the pelvis. Women typically develop chronic pelvic pain and infertility (due to destruction to the uterus, fallopian tubes, and ovaries). 

Some women with these conditions will not have any symptoms at all and are diagnosed when being examined or undergoing imaging/procedures for an entirely different reason. However, in most women, these conditions have a significant impact on menstrual health. Whenever you notice a change in your periods, do not hesitate to seek professional help. Timely diagnosis and treatment of most conditions yield positive outcomes in reproductive health.

References
 

1) Greene, A. D., Lang, S. A., Kendziorski, J. A., Sroga-Rios, J. M., Herzog, T. J., & Burns, K. A. (2016). Endometriosis: where are we and where are we going?. Reproduction (Cambridge, England), 152(3), R63–R78. https://doi.org/10.1530/REP-16-005 

2) Vannuccini, S., & Petraglia, F. (2019). Recent advances in understanding and managing adenomyosis. F1000Research, 8, F1000 Faculty Rev-283. 

https://doi.org/10.12688/f1000research.17242.1 

3) Practice Committee of the American Society for Reproductive Medicine. Electronic address: ASRM@asrm.org; Practice Committee of the American Society for Reproductive Medicine. Uterine septum: a guideline. Fertil Steril. 2016 Sep 1;106(3):530-40. DOI: 10.1016/j.fertnstert.2016.05.014. Epub 2016 May 25. PMID: 27235766. 

4) Obeidat, R. A., Aleshawi, A. J., Tashtush, N. A., & Alsarawi, H. (2019). Unicornuate uterus with a rudimentary non-communicating cavitary horn in association with VACTERL association: case report. BMC women's health, 19(1), 71. 

https://doi.org/10.1186/s12905-019-0768-4 

5) Rezai, S., Bisram, P., Lora Alcantara, I., Upadhyay, R., Lara, C., & Elmadjian, M. (2015). Didelphys Uterus: A Case Report and Review of the Literature. Case reports in obstetrics and gynecology, 2015, 865821. https://doi.org/10.1155/2015/865821 

6) Kaur P, Panneerselvam D. Bicornuate Uterus. 2020 Aug 10. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan–. PMID: 32809694. 

7) Jennings LK, Krywko DM. Pelvic Inflammatory Disease (PID). 2020 Jun 24. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan–. PMID: 29763134. 

8) Hoenderboom BM, van Benthem BHB, van Bergen JEAM, Dukers-Muijrers NHTM, Götz HM, Hoebe CJPA, Hogewoning AA, Land JA, van der Sande MAB, Morré SA, van den Broek IVF. Relation between Chlamydia trachomatis infection and pelvic inflammatory disease, ectopic pregnancy, and tubal factor infertility in a Dutch cohort of women previously tested for chlamydia in a chlamydia screening trial. Sex Transm Infect. 2019 Jun;95(4):300-306. DOI: 10.1136/sextrans-2018-053778. Epub 2019 Jan 3. PMID: 30606817; PMCID: PMC6585279.

KEYWORDS: periods, reproductive health, menstrual health