In women with regular menstrual cycles, an egg is usually released from the ovaries every month (‘ovulation’). However, in some women, the small fluid-filled sacs inside the ovaries (follicles) don’t always mature and ovulate (this typically affects women with polycystic ovarian syndrome). In this case, the release of eggs from the ovaries is unreliable – it either doesn’t occur at all, or only happens every now and again, leading to difficulty in falling pregnant.
If absent or irregular ovulation is contributing to your fertility issues, hormones and other special medications may be used to help your ovaries develop and release mature eggs. These medications may be used on their own to simply induce ovulation (‘ovulation induction’), with sexual intercourse then timed accordingly. However, these medications may also be used in combination with other fertility treatments if there are other factors contributing to your fertility issues. For example, if the quality and/or quantity of your partner’s sperm is also an issue (male-factor infertility), then simply getting the ovaries to release mature eggs is unlikely to be successful on its own. You may also need the help of artificial insemination (to insert a concentrated dose of sperm into the reproductive tract) or IVF (to collect the eggs for fertilisation outside the body).
The process we use to stimulate your ovaries to produce and release eggs is as follows:
Your fertility specialist will prescribe medication for you to take orally or by injection. There are a few different types of medications that may be used but they all work to increase the amount of follicle-stimulating hormone (FSH) in your body. Although your body naturally produces this hormone, the medication provides you with much more of it than what you would naturally produce on your own. The increased level of FSH is what causes the follicles inside your ovaries to develop and mature. At the start of puberty, you have around 400,000 follicles in your ovaries with the potential to develop into mature eggs. The number of follicles decreases year-on-year thereafter, with the greatest decline occurring after the age of 35.
We will monitor you closely with blood tests and ultrasounds to see how your follicles are responding to the medication and to monitor for any side-effects. The aim is to allow the follicles time to mature while preventing the premature release of any eggs (‘ovulation’).
You will usually be given an injection of human chorionic hormone (hCG) to trigger the release of eggs when the follicles are a good size. This is timed with sexual intercourse or artificial insemination to ensure there is sperm ready to meet the egg your ovaries release, in the hope that the egg and sperm will come together and develop into an embryo. Alternately, if ovarian stimulation is being used as part of the IVF process, then we won’t just ‘let nature take its course’. Instead, we will use ultrasound to help us physically retrieve the eggs your ovaries have produced. After we have collected your eggs, we will place them with your partner’s sperm in a special laboratory dish to fertilise. One fertilised egg (embryo) is then placed in your womb where it will hopefully ‘stick’ to the wall of the uterus and develop into a pregnancy.
Every woman responds differently to these medications. Thus, the dose of medication is tailored to each woman and closely monitored. However, even with this fine-tuning, sometimes the ovaries don’t respond well, in which case there may be no eggs or only a few eggs released. This is more likely to occur in older women (>37 years), women with elevated hormone levels, and women with reduced ovarian reserve (a low number of follicles to start with).
The type and dose of medication given will also depend on the type of fertility treatment you are having. If these medications are being used to facilitate the success of timed intercourse or artificial insemination, then we may use a more gentle mode of stimulation (e.g. oral tablets), as we are simply trying to mimic what would happen during your normal menstrual cycle – that is, have one egg lying in wait for your partner’s sperm to arrive.
However, if you are having this medication as part of the IVF process, then we would typically use injectable hormones at a dose that’s adequate for producing multiple eggs. Even if IVF circumstances are at their very best, not every egg placed with the male’s sperm in the laboratory will fertilise to form an embryo – and not every embryo will survive or be suitable for implanting into the womb. Therefore, the more eggs we make available for fertilisation by sperm during IVF, the higher the likelihood of producing a good number of high-quality embryos, which increases the chances of IVF success.
Yes, these medications do stimulate the development of multiple follicles, so the ovary may end up releasing more than one mature egg. While this is desirable for IVF where the aim is to collect as many eggs as possible, it’s not ideal when these medications are used with timed intercourse or artificial insemination, as there is then an increased chance of having twins (or more). Although twins may sound like a lovely idea, multiple pregnancies do come with risks, both for the mother and babies. Thus, your fertility specialist will watch out for this via ultrasound monitoring – if too many eggs are developing, we may recommend abstaining from intercourse or adjusting the dose of your medication.
Multiple pregnancy is not an issue if ovarian stimulation is being used as part of the IVF process, as the eggs are being collected for fertilisation outside the body (in a laboratory dish) and we only implant one embryo into the womb at a time.
You may have heard that one of the more unpleasant aspects of fertility treatment is the side-effects of the medications used to stimulate the ovaries. Unfortunately, these medications do make you feel ‘hormonal’ and you may find yourself experiencing exaggerated PMS symptoms. The most common symptoms are temporary physical side effects, such as nausea, vomiting, headaches, cramps and breast tenderness. Mood changes, including mood swings, anxiety and depression, are also common. Bear in mind, however, that the emotional demands of infertility or IVF treatment can lead to similar feelings.
If you have injections, these may cause local skin irritations, but it is rare to have an allergic reaction to the medications.
The key risk associated with this type of treatment, particularly when higher doses are used as part of the IVF process, is ovarian hyper-stimulation syndrome (OHSS). This represents the body’s exaggerated response to the excess load of circulating hormones. It is characterised by enlarged ovaries and fluid accumulation in the abdomen. The chance of OHSS occurring is greater in women who become pregnant during the cycle in which the hormones are given and in women with polycystic ovary syndrome (PCOS). Close monitoring allows us to discontinue or adjust your medication if we start to see the signs or symptoms of OHSS. Be reassured that your fertility specialist will explain all the symptoms you should look out for, so you can let them know if you experience anything concerning.
Ovarian stimulation plays a key role in many fertility treatments – from ovulation induction and timed intercourse to artificial insemination and IVF. For more information on how it could help you, make an appointment with one of our fertility specialists by calling Newlife IVF on (03) 8080 8933 or by booking online via our appointments page.