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How does IVF work?


Want to know how IVF works?

Here, we unravel the process of IVF (in vitro fertilisation) to help you kick start your research into the IVF journey.

Natural conception

To naturally conceive a child, four succinct steps must harmonise

  • An egg must be released from the ovary (ovulation)
  • Appropriate sperm needs to be placed in the upper vagina
  • Sperm must fertilise an egg (via the fallopian tube) to form the embryo
  • The resulting embryo must implant in the wall of the uterus.

When to investigate fertility?

Approximately 85-90% of women aged 25-35 years become pregnant in the first year of attempting to conceive a child. If natural conception does not occur by twelve months (or 6 months if aged over 35 years), you may wish to start seeking advice.

Your GP can play an important role at this point. They can test for irregular reproductive functions and assess critical elements such as sperm, ovulation and the fallopian tubes with relatively simple investigations. Prior to considering IVF, GPs can also provide helpful advice on lifestyle, nutrition and vitamin supplements.

For example, being overweight can significantly impair fertility by up to 50% in both females and males. These effects CAN be reversed with an effective combination of diet and exercise.

Referral to a fertility specialist

If you have been trying for some time to conceive, or the tests your GP has arranged reveal a problem that is preventing you from getting pregnant, you should see a fertility specialist. You will require a GP referral. Seeing a Fertility Specialist does not automatically mean that you will require IVF, there are other options that might be available to you, depending on the problem.

What’s involved in IVF?

IVF endeavours to significantly enhance the natural process of conception. It can be used to:

  • overcome disorders of ovulation
  • to increase the number of eggs available for fertilisation
  • to ensure that the sperm fertilise the eggs
  • to overcome an obstruction of the fallopian tubes

Each IVF clinic tends to develop their own IVF cycle protocol(s). The variability between clinics can impact the selection of treatments, timing of injections and laboratory analysis. In saying this, the general structure of an IVF cycle follows seven steps:

  1. Stimulation of the ovaries to produce multiple eggs
  2. Prevention of premature ovulation, so that the eggs are not lost
  3. Trigger ovulation, to release the eggs
  4. Collection of the eggs (just prior to their release) and sperm
  5. Fertilise and develop embryos in the laboratory
  6. Transfer the embryo/s to the uterus a few days later
  7. Support the uterus after implantation with medication

1.  Stimulation of the ovaries

Follicles, each containing a tiny egg, normally develop in the ovaries, with one follicle with one mature egg developing in each menstrual cycle as a result of FSH (follicle stimulating hormone) being produced from the brain.  In an IVF cycle, FSH is injected to stimulate the development of multiple follicles. FSH is administered daily and is commonly taken for 9 – 12 days.

2.  Prevention of premature ovulation

The release of a mature egg from the ovary (ovulation) is normally triggered by a dramatic surge of LH (luteinising hormone). In IVF, the LH surge is actively delayed via the administration of either a GnRH agonist or GnRH antagonist. These drugs suppress the natural ovulation process, thereby preventing premature release of the developing eggs from the follicles

3.  Trigger ovulation

Once the follicles are mature a trigger injection of hCG will be given. hCG replaces the natural LH surge and prepares the follicles for ovulation. The trigger injection is given 36 hours before the scheduled egg retrieval.

4.  Collection of eggs and sperm

Guided by an internal (transvaginal), ultrasound the available eggs and surrounding fluid of the follicles are collected. Shortly after egg collection, the male partner provides a sample of sperm.

5.  Fertilise embryos in the laboratory

The eggs and sperm are fertilised in the laboratory. The embryos are then left to develop for 5 days in the laboratory.

6.  Transfer the embryo(s)

Under ultrasound guidance a fine plastic catheter containing the embryo is passed through the cervix into the uterus.  Any remaining healthy embryos that have not been transferred can be frozen for future use without the need to undergo another stimulated cycle.

7.  Support the uterus after implantation

To support the development of pregnancy, progesterone (hormone) must be abundant in the uterus. In IVF, additional hCG or progesterone is required until the outcome of the potential pregnancy is known.

The TWW (two-week wait)

Now the cycle is complete, the waiting game starts. The success of embryo implantation can be known 16 days after egg collection, via a pregnancy test.
The IVF journey can accommodate couples, singles and same sex couples. In each case, the reason for choosing IVF can vary, which can alter the process outlined above.

Support:   Join our onilne Conception & Fertility Forum to get your questions answered

Content for this article was kindly provided by Sydney IVF

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