New life begins when an egg from a woman is fertilised by sperm from a man. Ovulation occurs around 14 days before the start of the menstrual period, when an egg (ovum) is released from one of the ovaries. The egg is swept into the nearby fallopian tube and ushered towards the uterus (womb). If the egg is fertilised on its journey, it lodges in the womb lining (endometrium). Pregnancy then begins. The odds of a young fertile couple conceiving by having sexual intercourse around the time of ovulation are approximately one in five every month. A couple isn’t thought to have fertility problems until they have tried, and failed, to conceive for one year. Approximately 20 per cent of couples experience difficulties. In most cases, the couple can be helped with assisted reproductive technologies. Around 40 per cent of fertility problems originate in the woman. Female fertility problems include failure to ovulate, and abnormalities of the fallopian tubes or uterus.
The menstrual cycle is orchestrated by a number of glands and their hormones working in harmony. For ovulation to occur, a part of the brain called the hypothalamus prompts the nearby pituitary gland to secrete hormones that trigger the ovaries to ripen eggs. Irregular or absent periods indicate that ovulation may be irregular or absent too. The age of the woman is a significant fertility factor. The chance of pregnancy for a woman aged 40 years and over is only five per cent per menstrual cycle. It is thought that ageing eggs may be the cause. A woman is born with her entire egg supply and, as time passes, these eggs become less viable. Other difficulties for the older woman include increased risk of miscarriage and genetic abnormalities in the unborn baby.
At the time of ovulation, the ovaries produce small cysts or blisters called follicles. Typically, one follicle ripens to release an egg. In polycystic ovary syndrome, the follicles fail to ripen, forming little cysts at the periphery of the ovary and often releasing male sex hormones.
The sperm fertilises the egg on its journey down the fallopian tube. A blocked or scarred fallopian tube may impede the egg’s progress, preventing it from meeting up with sperm. A surgical procedure called laparoscopy can be used to check for obstructions.
The fertilised egg lodges in the lining of the uterus. Some uterine problems that can hamper implantation include:
At the top of the vagina is the neck or entrance to the uterus, called the cervix. The cervix has a small central hole (the os) that allows passage of menstrual fluid and other secretions out of the uterus. Ejaculated sperm must travel through the cervix to access the uterus and fallopian tubes. Cervical mucus around the time of ovulation is normally thin and watery so that sperm can swim through it. However, thick or poor quality cervical mucus can hinder the sperm.
Endometriosis is a condition in which cells from the lining of the uterus (the endometrium) migrate to other parts of the pelvis. This can also lead to fertility problems. Idiopathic infertility
For around one in 10 couples investigated for infertility, no cause is found. This is called ‘unexplained’ or ‘idiopathic’ infertility.
Investigating suspected infertility requires a number of tests for both the woman and her partner.
Tests for the woman may include:
Treatment options for female infertility depend on the cause, but may include:
New life begins when an egg from a woman is fertilised by sperm from a man. Around 20 million sperm per millilitre (ml) need to be present in the ejaculate, with enough mobility and strength to swim the journey to the fallopian tube, where conception normally takes place. The odds of a young fertile couple conceiving by having sexual intercourse around the time of ovulation are approximately one in five every month. A couple isn’t suspected of fertility problems until they have tried, and failed, to conceive for one year. Approximately 20 per cent of couples experience difficulties. In most cases, the couple can be helped with assisted reproductive technologies. Around 40 per cent of fertility problems originate in the man. Male fertility problems include poor quality sperm or blockages in the tubes of the reproductive system.
Sperm are made in the testicles. During ejaculation, sperm are pushed (by muscular contractions) through a series of small tubes called the epididymis, and mixed with seminal fluid from structures called seminal vesicles. The prostate gland also adds fluid. The semen is forced along a larger tube (vas deferens), into the urethra and out of the penis. In around one in three cases of male infertility, blockages or absences of tubes (including the vas deferens) are the cause of infertility. Causes may include vasectomy and injury.
Problems with sperm numbers or quality are thought to be caused by genetic factors. Melbourne researchers have discovered that tiny fragments of the male chromosome may be missing in some men with sperm problems. This may cause:
Functional problems that can cause or contribute to male infertility include:
The levels of male sex hormones are regulated by a series of glands and their hormones. The pituitary gland in the brain influences hormone production in the testicles, under the guidance of another brain structure - the hypothalamus. A relatively uncommon cause of male infertility is the failure to make enough of the hormone gonadotrophin.
For around one in 10 couples investigated for infertility, no cause is found. This is called ‘unexplained’ or ‘idiopathic’ infertility.
Investigating suspected infertility requires a number of tests for both the man and his partner.
Diagnosing male infertility may involve:
There are no treatments available that can improve the quality of a man’s sperm. However, techniques can increase the odds of conception using the existing sperm quality.
Treatment depends on the cause, but may include:
Treatment options for poor sperm quality include artificially inseminating the partner with a concentrated sample of the man’s semen