How does IVF work?
Getting pregnant is often more difficult than people think, especially as we get older. It’s helpful to be aware of the fertility issues that people can have when they are trying to conceive and how IVF works to address these problems.
Fallopian tube damageIVF was originally developed to overcome damage to the fallopian tubes. Blockage in a fallopian tube prevents sperm from reaching the egg to fertilise it. Fertilisation in the laboratory overcomes this problem. During IVF, your ovaries are stimulated to produce eggs, which are retrieved during a short procedure called egg collection. Your eggs are then fertilised with your partner’s or donor sperm in the laboratory, and your fertilised embryos are placed into your uterus through the cervix where they can implant and grow, so the fallopian tubes are bypassed all together.
Endometriosis is a condition where tissue that normally grows in the uterus implants and grows in other places in your body and can cause scarring, which may block your fallopian tubes. If you have mild endometriosis, a procedure known as a laparoscopy may improve your chances of a successful pregnancy. If your endometriosis is severe, you may still have a chance of getting pregnant naturally, however if you have damage to your fallopian tubes your doctor is likely to recommend IVF. You may end up choosing IVF because you prefer this to surgery, or you may already have had surgery but not conceived. If you endometriosis is not severe enough for surgery but you haven’t conceived after a few years of trying then you may also consider IVF.
Age and your eggs
A woman’s most effective reproductive years are in her 20s. Fertility gradually declines in the 30s, particularly after age 35. Even a healthy, fertile 30-year-old woman has only a 20 percent chance of getting pregnant naturally each month. The impact of age on your eggs is twofold. Firstly, as you get older, your eggs decrease in number. Age is the biggest factor affecting egg supply. The older you get, the fewer eggs you have. Women are born with their lifetime supply of eggs, your body does not produce more eggs. Secondly, egg quality deteriorates with age and this has a significant impact on the viability of embryos and chromosome disorders become more likely. For women, the ability to conceive is influenced by the quality of her eggs. Decreased egg quality means it becomes more difficult for the sperm to fertilise the egg naturally.
IVF and egg quantity
In a normal menstrual cycle you release one egg each month. In an IVF treatment cycle, we are able give you a course of fertility drugs to stimulate the development of follicles in your ovary to produce a number of eggs, (your chances of becoming pregnant are greater with more eggs). We collect your eggs during a simple procedure and put them in to a special culture medium. We then safely transfer them to an incubator to provide exactly the right environment and temperature conditions for them. We spin the semen sample in a special media to isolate the good quality sperm and then wash this in another media to purify the sample. The next step is to fertilise your eggs with the sperm to form embryos. We then grow your precious embryos in carefully controlled conditions until they’re ready to be transferred into your womb. Usually we will transfer one embryo, and hopefully you may have surplus embryos which can be frozen and used either if initial treatment is not successful or if you wish to have another child.
IVF and egg quality
If the quality of an egg is poor, then most likely it will not fertilise. Some may even fertilise but then the embryo doesn’t implant or results in a miscarriage. There are a number of things which can be done during an IVF treatment cycle to optimise embryo selection and increase your chances of pregnancy.