Introduction

Overview of Chlamydia

Chlamydia trachomatis is the gram-negative, anaerobic bacterium responsible for causing the sexually transmitted infection (STI), chlamydia.¹ Globally, chlamydia is the most common STI.³ STIs that are left untreated may cause complications that can lead to long-term health problems in both people assigned female at birth (AFAB) and people assigned male at birth (AMAB). This STI is primarily transmitted through oral, vaginal, and anal sex. If not treated, several complications can arise after long-term infection, including fertility in people AFAB and AMAB, ectopic pregnancies in people AFAB and in pregnant people, which can lead to premature birth.^1,3

In 2020, there were an estimated 128.5 million new infections with Chlamydia trachomatis in adults aged 15-49 years, with prevalence estimated to be 4.0% in women compared to 2.5% in men. 

Importance of understanding complications

Chlamydia has a high asymptomatic rate: many individuals infected with chlamydia will have mild to no symptoms, though if symptoms do occur, they usually appear up to 3 weeks post exposure to the bacterium. The most effective way of preventing chlamydia is via the correct and consistent use of barrier contraceptives such as condoms.^1,3

Complications in people AFAB

Long-term untreated chlamydia is known to cause a plethora of complications in people AFAB. Evidence shows that people AFAB who have been diagnosed with a chlamydia infection at least once have a 30% increased risk of developing PID, experiencing ectopic pregnancies, and tubal factor infertility in their reproductive life. This risk increases further when the infection goes untreated for over a 1 year.^4,5

Pelvic Inflammatory Disease (PID)

PID is an inflammation of the upper genital tract mostly associated with an ascending infection from the lower genital tract in people AFAB. It’s a condition that affects the ovaries, fallopian tubes, and/or uterus. It mostly occurs in people AFAB aged 15-25. However, the number of cases has been steadily decreasing. Inflammation in the reproductive organs found in the upper genital tract leads to adhesions, scarring, obstruction of the fallopian tubes. Individuals with PID present with a number of symptoms such as dyspareunia, vaginal discharge, abdominal and/or pelvic pain, and/or abnormal vaginal bleeding. Early treatment of PID can prevent complications associated with the condition like chronic pelvic pain, ectopic pregnancies, and infertility. However, even with timely diagnosis and treatment, there is still potential for complications to develop eventually.^1,6

Infertility

While the impact of chlamydia infection on infertility is not completely established, there is an important association between these two factors. Due to inflammation from PID in reproductive organs such as the fallopian tubes and ovaries, there is an impact on fertility in this way.^7,8

Ectopic Pregnancy

This can occur in people of childbearing age with female reproductive organs that developed PID following a chlamydia infection that led to tubal damage.¹

Chronic Pelvic Pain

This is often present following adhesions that form due to PID.¹

Pregnancy Complications

In patients with a previous history of chlamydial infection, they may experience pregnancy complications such as preterm births and low birth weight. Additionally, having a chlamydial infection in pregnancy increases the risk of premature prelabour rupture of membranes (PPROM) and prelabour rupture of membranes (PROM); infection during pregnancy also exposes the baby to neonatal infections such as conjunctivitis and pneumonia.^1,9

Complications in people AMAB

Epididymitis

In people AMAB, the chlamydia infection can spread to the epididymis and testicles, causing swelling and pain. This is a rare complication known as epididymitis or epididymo-orchitis. This inflammation can be cured using antibiotics; however, long-term it may cause infertility.^1,10

Chronic prostatitis

This is a common urological disorder that occurs in people with AMAB as it’s an inflammation of the prostate. It has been etiologically associated with chlamydia infection and is considered a long-term complication of the STI.¹¹

Reactive Arthritis

Sexually acquired reactive arthritis (SARA) is a condition where inflammation of an individual’s eyes, urethra or joints occurs. It usually appears within the first few weeks of being infected with chlamydia. It can also affect people AFAB who have been diagnosed with the STI but occurs more commonly in people AMAB. It is non-curable, but often individuals notice an improvement in a few months. Symptom relief can be achieved through the use of non-steroidal anti-inflammatory drugs.^1,12

Infertility

In people AMAB, following long-term infection with chlamydia, damage can be seen to DNA within sperm cells that causes a high percentage of poorly functioning cells. This contributes to fertility issues. 

Complications in Newborns

In children born vaginally to mothers infected with chlamydia, there is a risk of perinatal transmission from infected birth parent to child. The infant will acquire a chlamydia infection that presents as neonatal pneumonia or neonatal conjunctivitis. It is estimated that 50-70% of infants born to birthing parents with the infection will acquire the STI. The recommended treatment for these infants is systemic therapy with erythromycin. It is recommended that pregnant individuals are screened for possible chlamydia and treated with prophylaxis early to prevent transmission to their infant.¹³

Complications in everyone

Everyone that leaves their chlamydia infection untreated is at risk of developing a urethral infection known as nongonococcal urethritis (NGU). 

Research has shown that infection with chlamydia enhances susceptibility to HIV infection.¹⁴

Furthermore, chlamydia infection can lead to stigmatisation and have an effect on personal relationships; while these aren’t quantifiable complications, they’re worth consideration. 

Management and Prevention of Complications

Screening and Early Detection

As the incidence of chlamydia continues to increase within the population, there are national screening guidelines in place that are used to inform how to diagnose and, when needed, treat the infection to avoid long-term complications.¹⁵

Diagnosis

Chlamydia diagnosis can only be confirmed via laboratory testing. In the UK, you can get tested even without symptoms. Furthermore, as part of the National Chlamydia Screening Programme (NCSP), if you are a person AFAB aged 25 years old or less, you may be offered a chlamydia test when visiting certain health service providers, such as a pharmacy or general practitioner. 

The lab tests for chlamydia are highly reliable, painless, and simple. They involve collecting a sample of cells that will be sent to the laboratory for analysis; these samples can often be collected individually and are done in two main ways:

• Swabbing - a cotton bud is swiped over the area that may be infected, usually the anogenital area for people with vaginas
• Collecting a urine sample - usually asked for people AMAB and AFAB

The infection may not always be present right away after exposure therefore it is recommended to wait 2 weeks before testing or until you begin to display symptoms.

You can get a free, confidential test from a sexual health clinic, your GP, most contraceptive clinics and a genitourinary clinic. In some areas of the country, you may be able to order postal testing kits. 

Symptoms

Though most people infected with chlamydia may not have symptoms, some might, and it is useful to know what to look out for. In people assigned female at birth (AFAB), the most commonly infected anatomic site is the cervix, this can then manifest as cervicitis, urethritis, proctitis, perihepatitis, or pelvic inflammatory disease (PID). Each of these manifestations has its own associated symptoms:¹ 

• Cervicitis. People with vaginas may experience abnormal looking vaginal discharge, bleeding, dysuria, and abdominal pain. A small percentage of these people may have easily-induced endocervical bleeding as a result of inflammation. Some people may complain of post-coital bleeding or metrorrhagia^1,16
• Urethritis. Most commonly in people AMAB. Associated symptoms are dysuria and urethral discharge. In people AFAB, they may notice an increased frequency of urination or dysuria¹
• Proctitis. As a result of rectal infection with chlamydia; often asymptomatic but patients may present with rectal bleeding, pain, and discharge post-intercourse alongside fever or general malaise¹
• Perihepatitis. Also known as Fitz-Hugh-Curtis syndrome which occurs when ascending infection causes liver capsule inflammation; patients present with pain in the upper right quadrant of the abdomen¹
• Pelvic Inflammatory Disease (PID), It caused by ascending infection into the upper genital tract; patients mostly present with abdominal or pelvic pain, sometimes accompanied with symptoms of cervicitis. They may also present with fever, chills, lower back pain, and vomiting^1,6

Summary

Chlamydia is a common STI caused by a gram-negative bacteria that is asymptomatic in most. It can only be diagnosed through urine samples or swabbing that is tested in a laboratory. When caught early, it is curable with a short course of antibiotics. However, if an individual is infected with the STI long-term, there are various complications that arise that are harder to treat and manage. In people AFAB, these complications are pelvic inflammatory disease, ectopic pregnancy, chronic pelvic pain, and infertility. In people AMAB, the complications can be epididymitis, chronic prostatitis, sexually acquired reactive arthritis, and infertility. In everyone, there is an increased risk of acquiring HIV or nongonococcal urethritis, an inflammation of the urethra. Because of these potential complications, there are national efforts in the form of free testing services for chlamydia and a national screening programme to help sexually active individuals catch the infection before it progresses too far. It is recommended that sexually active people are tested frequently.