Infertility & its causes

You only need three things to get pregnant: you need to produce an egg (ovulation), you need to have good quality sperm and the egg and the sperm need to be able to meet (usually in the Fallopian tube) and fuse (fertilisation) and implant (conception). It sounds simple, but in order to achieve this, hundreds of synchronised hormonal, chemical and physical events must take place. Nature has developed a complex sequence of events with many control mechanisms, and many steps where things can go wrong.

When the egg and sperm fuse, they become one cell. This cell divides to become 2 cells, these 2 cells divide to become 4 cells, 4 divide to become 8 and so on. This ball of cells is now called an embryo. The cells continue to multiply and the embryo eventually settles in the lining of the womb (implantation) and so the early fetus develops.

"Infertility" is defined as the failure to get pregnant after one year of having regular, unprotected intercourse.
Around 1 in 6 couples have difficulty in achieving a pregnancy and this proportion is increasing, largely for two reasons: firstly, women are delaying starting their families in order to develop their careers and, secondly, sperm counts are falling. However, with the appropriate help, the vast majority of couples can realise their dream of starting a family.

There are many reasons why you might be having difficulty getting pregnant but broadly speaking they are due to problems of ovulation and egg quality, problems of sperm quality, problems with the Fallopian tubes or a combination of these factors.

Common egg problems:

• Polycystic ovary syndrome (PCOS), resulting in infrequent ovulation (for further information please click HERE).
• Being over- or underweight, resulting in irregular ovulation
• Taking medications that affect ovulation
• Increasing age. Unfortunately, as a woman gets older, the quality of her eggs decreases and conception is more difficult.

Common sperm problems:
In many parts of the world, for reasons that have yet to be fully explained, sperm counts are falling. As a result, we are seeing more men with:

• Too few sperm
• Not enough motile sperm
• Minor genetic problems that affect sperm counts and quality
• Genetic problems or past infection that have blocked the vas deferens (the tube which connects each testicle with the penis).

Common Fallopian tube problems:

• Past pelvic infection
• Past pelvic surgery

Endometriosis:
Endometriosis is a common condition where the cells that line the womb (and bleed each month with a menstrual period) occur outside the womb, in the abdomen. Moderate and severe disease can affect the function of the ovaries and the Fallopian tubes but even mild endometriosis can have a negative effect on a couple’s fertility, possibly by subtle effects on the function of sperm or the Fallopian tubes.

Unexplained infertility
In a proportion of couples we can’t find an obvious cause for their subfertility and this is termed "unexplained infertility". It doesn’t mean that there is nothing wrong, it just reflects our state of knowledge at the present time, and it might be due to a subtle problem with one of the hundreds of things that are required for successful conception and implantation.