Fertility Illustrations

These lovely illustrations give you a basic idea of how your reproductive system works, as well as conditions that can affect you or your partner’s fertility. For further information, seek medical professional advice.



During ovulation, an egg containing the mother’s genes is released through the ovary wall and into the fallopian tube. It’s here that it meets the sperm containing the father’s genes that have made their way into the upper parts of the fallopian tube. This is where ovulation occurs as just one sperm successfully fertilises the egg, creating a whole new genetic blueprint for the baby. The combined sperm and egg are now called a zygote. The egg then starts to divide as it travels through the fallopian tube, towards the uterus. First two cells, then four, then eight, until they form a ball called a morula. This then forms a blastocyst about five days after fertilisation, which proceeds in the next day or two to embed itself into the soft lining of the uterus. It is now that pregnancy officially starts, although you technically date it from the first day of your last period.


A hormone-dependent chronic inflammatory disease, in which tissue that normally lines the inside of the uterus, otherwise known as the endometrium, grows outside the uterus. It can be extremely painful and can lead to fertility problems, such as difficulty getting pregnant or not being able to get pregnant at all. There are treatments to relieve symptoms and improve fertility. 


A hormononal imbalance related condition characterised by cysts that grow on a women’s ovaries, affecting how they work. Common symptoms include irregular periods, high levels of male hormones in the body, which can contribute to excess facial or body hair, as well as polycystic ovaries, which become enlarged as they contain fluid filled sacs that surround the eggs. It can affect a women’s fertility as sometimes these sacs aren’t able to release an egg, which means that ovulation doesn't take place.


This is a fluid-filled sac within the ovary. They don’t tend to cause symptoms and can naturally disappear on their own, without treatment. Symptoms might include pain during sex, pelvic pain, the need to pee often, bloating, as well as difficulty getting pregnant, although the latter isn’t that common.


A mildly misshapen uterus characterised by a dip in the top. It may not cause any fertility issues and there’s no concrete evidence as to whether it causes an increase in pregnancy loss or not.


The septum divides the uterus partially or completely. It can increase a women’s risk of subfertility, recurrent miscarriage, and preterm birth.


The uterus is shaped like a heart. It doesn’t seem to cause fertility issues but can cause complications within pregnancy.


Uterine malformation where you have two uteruses, two cervixes, and in some cases, two vaginas. It doesn’t seem to cause fertility issues but can result in complications during pregnancy and delivery.


A non-viable fertilised egg implants itself into the uterus. It’s non-viable as something goes wrong during the fertilisation process at conception, which means the foetus and placenta don’t form properly and a baby doesn’t develop. There becomes an abnormal overgrowth of cells that would normally form the placenta. You may have no symptoms, but some might be bleeding from the vagina, pain or a lot of quick growth around the tummy. Treatment involves removing the abnormal tissue.


A fertilised egg implants itself outside of the uterus, usually in the fallopian tubes, which connect the ovaries to the uterus. They can sometimes occur elsewhere in the body though. Symptoms include vaginal bleeding, pain in the shoulder, tummy pain or discomfort going to the loo. If left untreated, it can be life-threatening.


Growths (usually non-cancerous) that develop in the wall of the uterus. They’re made up of muscle and fibrous tissue. Symptoms might include things like heavy or painful periods, lower back pain, needing to pee a lot, discomfort during sex or constipation. They can affect fertility and tend to be treated if they’re causing symptoms.


When cells of the inner lining of the uterus (endometrium), are found in the uterus wall (myometrium). Symptoms might include heavy, painful or irregular periods. It may impact fertility and treatment can alleviate symptoms.


The ovaries are two reproductive glands that produce eggs, as well as the hormones oestrogen and progesterone. Ovarian cancer is when cells in the ovary grow out of control and form a tumour. Symptoms might include things like bloating, needing to pee often, discomfort in the tummy and pelvic area. Treatment can affect fertility.


The male reproductive system includes the testes, spermatic ducts, accessory glands including the seminal vesicles and prostate gland, and the penis. They work together to produce and release semen. The urethra carries the semen, containing sperm, through the penis and into the female reproductive system, when you have sexual intercourse. It’s also part of the urinary system as urine passes through it as it leaves the bladder.


By the end of a mother’s first trimester of pregnancy, a baby girl has all the eggs she’ll ever carry in her lifetime. They lie dormant in the ovaries until she reaches puberty, when they’re released once a month. Each month of a cycle, several eggs begin to mature in the ovaries, but normally only one developed egg is released. This happens during ovulation. The egg has a very short lifespan and has to be fertilised within 12 to 24 hours, otherwise it disintegrates, and is expelled during your period. If two eggs are released during ovulation and both are fertilised, you get non-identical twins. If a single fertilised egg splits during the early stages of cell division, you get identical twins, which have their own placenta. If they split in the later stages of cell division, they share a placenta. The egg is the largest cell in the body and is similar in size to that of a grain of sand. 

Glands that produce and secrete hormones


The endocrine system is where hormone production takes place. Certain organs secrete hormones into the bloodstream, which then travel throughout the body. They act as chemical messengers, triggering changes in tissues that regulate many bodily processes such as digestion, reproduction and pregnancy.

  • Hypothalamus: Links the nervous system to the endocrine system
  • Pituitary gland: Sometimes called the ‘master gland’ as it controls the function of other endocrine glands
  • Thyroid gland: Secretes hormones that control growth and metabolic rate. Undiagnosed thyroid disorders can cause fertility difficulties
  • Parathyroid glands: Attached to the thyroid and control calcium levels in the blood and bones
  • Adrenal glands: Produce hormones responsible for the ‘flight or fight’ response, help to regulate blood pressure and metabolism, and release small amounts of oestrogen and testosterone
  • Pancreas: Makes insulin and glucagon, which control blood glucose levels 
  • Testes: Secrete testosterone, which is responsible for the development of male sexual characteristics and maintains a man’s libido (sex drive)
  • Ovaries: Produce two hormones oestrogen and progesterone, which regulate the menstrual cycle, pregnancy and birth


Shortly before birth, the testes which have formed in a baby boy during the mother’s pregnancy, descend into the scrotum. However, sometimes this doesn’t happen and one or both testicles stay in the abdomen and only move part the way down. The problem with this is that normal sperm production requires a temperature a few degrees lower than the body temperature, which is why testicles hang down in the scrotal sac outside the body. If a man has two undescended testicles and they’re not corrected from a young age, it can cause infertility.


The testes are two small oval shaped organs located in the scrotal sac outside the body, one on either side of the penis. They are responsible for producing sperm and secreting testosterone. Sperm is produced in the seminiferous tubules. They then move through the epididymis where they mature and combine with other fluids to form semen, until they reach the vas deferens, where they await ejaculation.


The prostate is a small gland between the bladder and penis, that helps to make the fluid that makes up semen, which carries the sperm. Prostate cancer develops when cells in the prostate, begin to reproduce uncontrollably. Treatment can cause infertility, so a man may wish to store sperm in a sperm bank, before treatment.


During sexual intercourse, an erect penis is inserted into the vagina. During orgasm, the penis releases semen, which contains sperm, that start to swim up from the vagina, through the cervix, into the uterus and into the upper parts of the fallopian tubes. Not all the sperm make this journey and are flushed out of the vagina. However, some survive for up to five days. It only takes one strong swimmer to fertilise an egg. When this happens, only the head penetrates the egg, as the long tail of the sperm breaks off and a chemical change in the egg stops other sperm from getting in. Unlike women who have a set number of eggs, men produce sperm throughout their lifetime.


Testicular cancer happens when cells begin to reproduce uncontrollably within the testes. Signs could be a lump or any sort of ache or pain. Treatment can potentially cause fertility problems. A man may wish to store sperm in a sperm bank, before treatment.


An enlargement of the veins in the scrotum, similar to a varicose vein you might see in your leg. They’re a common cause of low sperm production and decreased sperm quality, which can impact fertility and risk of miscarriage. However, not all varicoceles affect sperm production, and many don't need treatment. If a varicocele causes symptoms such as a very sharp or dull discomfort, it often can be repaired surgically.