How Can Sexually Transmitted Infections Affect Fertility?

Unfortunately, along with sex comes the risk of catching a sexually transmitted infection (STI). You get an STI by having vaginal, oral or anal sex with a person who has an infection. Four STIs are curable, including: trichomoniasis; chlamydia; gonorrhoea; and syphilis. Four STIs are caused by viruses and are incurable, including: human papillomavirus (HPV); herpes simplex virus (HSV or herpes); hepatitis B; and human immunodeficiency virus (HIV).

You may see the terms STI and STD (Sexually Transmitted Disease). What is the difference? In 1999, the WHO recommended the use of the term Sexually Transmitted Infection rather than disease because STI is a broader term. An infection is a colony of parasites that may or may not cause symptoms. A disease is where the infection leads to an issue. Therefore, the term STI is more accurate as many STIs have no symptoms, but they can be harmful to your health and be passed on to other people.

In this chapter of my book I will describe each STI, its symptoms, diagnosis, treatment and whether it affects fertility. In this blog, I have just written a short summary of each STI.

Let’s discuss the four curable STIs.

Trichomoniasis
This is an STI caused by the protozoan parasite Trichomonas vaginalis (TV). It is the most common curable STI. It infects the vagina and urethra in women and the urethra, head of the penis and prostate gland in men. If you have trichomoniasis whilst you are pregnant, it may cause the baby to be born prematurely and have a low birth weight. There is a link to male and female infertility.

Chlamydia
Chlamydia is caused by the bacterium Chlamydia trachomatis. Chlamydia is the most common bacterial STI in the United Kingdom and more women are infected than men. Anyone can catch chlamydia through unprotected vaginal, oral or anal sex. In about half the women infected with chlamydia, the infection causes pelvic inflammatory disease (PID). This can cause permanent damage to a woman’s reproductive system, making her infertile.

Gonorrhoea
Gonorrhoea is caused by the bacterium Neisseria gonorrhoeae that infects warm, moist areas of the body including the: urethra; vagina; female reproductive tract (fallopian tubes, womb and cervix); anus; eyes; and throat.  It is transmitted by vaginal, oral or anal sex or by sharing sex toys and has similar symptoms, treatment and outcomes on fertility to chlamydia.

Syphilis
Syphilis is an STI caused by the bacterium Treponema pallidum. It can be transmitted through vaginal, oral or anal sex, but also skin contact with the sores or rash and using sex toys contaminated with the bacteria. Syphilis can be transmitted from a mother to her unborn baby. There is no indication that it causes infertility.

Now we will discuss the four incurable STIs caused by viruses.

Human papillomavirus (HPV)
HPV is the most common STI. HPV is a group of more than 150 related viruses that affect the skin and moist membranes lining the body but only a few cause problems. About 80% of sexually active people will catch HPV at some point. Different HPVs affect different parts of the body and can cause lesions. Some HPVs cause genital warts and 13 strains lead to cancers including: cervical cancer in women; or penile/anal cancer in men. In both sexes’ HPV can cause cancer of the throat. Cervical cancer is the most common cancer in women under 35 and the majority of cervical cancer is caused by specific strains of HPV. Recent research has suggested there might be a link with infertility.

Genital herpes
Genital herpes is a common STI that is caused by the Herpes simplex virus (HSV). Herpes can be transmitted by vaginal, oral or anal sex, or by close contact with somebody who has the infection including oral/genital or finger/genital contact. In the United Kingdom it is more common in women. There does not seem to be a link to infertility.

Hepatitis
Hepatitis is a group of infections that cause inflammation of the liver. There are five hepatitis viruses; A, B, C, D and E. The most common types are A, B and C. Hepatitis A is more often transmitted by food that has been handled by an affected worker and is not considered an STI. Hepatitis B and C can be transmitted through sex; B more than C.  Apart from sex, infection with hepatitis B and C could be the result of using infected needles such as: when having a tattoo or piercing; or sharing drugs or needles; or mother to child transmission during pregnancy. Both hepatitis B and C might become ‘chronic’, which means that the infection never cures and might worsen over time. Hepatitis affects the human liver, which is one of the most important organs of the body and it can cause serious illness and death. Hepatitis B is associated with impaired fertility.

HIV/AIDS
HIV is caused by a retrovirus that occurs as two types; HIV-1 and HIV-2. The final stages of HIV infection causes acquired immunodeficiency syndrome (AIDS). With HIV the virus attacks a type of white blood cell called the CD4 T cell, resulting in weakening of the immune system so the patient is unable to fight infections and disease. HIV is carried through bodily fluids, such as semen, anal or vaginal fluids, breast milk and blood. It is transmitted through sexual intercourse without a condom; sharing needles with people who inject drugs; and from a HIV positive mother to her child during pregnancy, childbirth or breast-feeding. The majority of people in the Western world catch HIV through unprotected sexual intercourse. There is no direct link with infertility but some of the symptoms may cause infertility such as weight loss.

Basic prevention for all STIs
The way to avoid getting an STI is to not have sex or to only have sex in a monogamous relationship. Anyone having casual sex or sex with a new partner, is recommended to use a condom for all sexual activity from start to finish to prevent the transmission of an STI. But a condom will not protect against all infections, so to avoid STIs the most effective way is to limit the number of sexual partners. Anyone sexually active should be tested at least once a year for STIs, every three-six months if they are having multiple partners or immediately if they have any symptoms. This can be arranged through a doctor or local family planning or sexual health clinic. When starting a new relationship, it is sensible for both partners to be checked for STIs before starting to have sex.

Read more
Your Fertile Years is available to pre-order on Amazon now. Contact joyce.harper@ucl.ac.uk if you would like Joyce to give a talk to any group or at any event.

Blogs
Chapter 1: Knowing Your Body; Understanding Your Menstrual Cycle And Fertile Window
Chapter 2: The biological clock, female fertility decline
Chapter 3: Optimising your reproductive health
Chapter 4: Everything you should know about sex
Chapter 5: If you do not want to become pregnant, how do you prevent it?

And videos to accompany the blogs on my YouTube Channel
Why I wrote Your Fertile Years
Chapter 1: Knowing your body
Chapter 2: The biological clock
Chapter 3: Optimising reproductive health
Chapter 4: Sex
Chapter 5: Contraception
Chapter 6: STIs
Chapter 7: Pregnancy

9 things you should know if you want kids in the future

Image credit: https://hypsouthwark.org.uk/portfolio/stis/