Many couples are able to conceive and establish a healthy pregnancy by having infertility treatment. One of the most used methods is in vitro fertilisation, which was first performed successfully in 1978. The overall process of in vitro fertilisation is described in this guide; this article outlines the different variations in IVF that have been developed over the last 30 years and that are offered by fertility clinics around the world.
This variation on in vitro fertilisation does not involve stimulating the woman’s ovaries to produce several eggs for collection. Just the one egg produced as part of her normal menstrual cycle is collected and then combined with her partner’s sperm to achieve fertilisation and, hopefully, a viable embryo.
This method of in vitro fertilisation has the advantages that it does not carry the risk of ovarian hyperstimulation, and it is also more acceptable to some cultures and religious groups as no spare embryos are created, which may then need to be disposed of or frozen. It also has the same risk of multiple pregnancy as natural conception.
On the downside, the success rates for natural cycle in vitro fertilisation are not that high. To be fair, the statistics are not readily available as so few procedures of this type are performed. As an example, figures published by the UK’s Human Fertilisation and Embryology Authority (HFEA) show that only one woman of the 26 aged under 35 became pregnant in 2008 as a result of natural cycle in vitro fertilisation.
This procedure is performed in exactly the same way as standard in vitro fertilisation except that the hormones used to stimulate the ovaries to produce several eggs are used at a lower dose or for a shorter time. This can reduce the risk of ovarian hyperstimulation syndrome in women who have developed this in previous in vitro fertilisation cycles, and in women who have polycystic ovary syndrome (PCOS).
Mild stimulation may also omit the initial treatment to suppress your own menstrual cycle, which means you may not find this phase of treatment as uncomfortable, as no menopausal-like symptoms will be apparent.
Disadvantages of this form of in vitro fertilisation are reduced numbers of eggs available for collection, and so potentially fewer embryos to choose from for transfer. However, because the ovaries are not stimulated in the same way, you do not have to wait so long to repeat a cycle of in vitro fertilisation. You can have three to four cycles within six months, as long as they all involve only mild stimulation.
Data published in The Lancet have shown that after one year of trying for a baby with mild stimulation IVF, 43.4 % of women became pregnant compared with 44.7 % having standard in vitro fertilisation, which is hardly any difference. The comparable results, combined with the significant difference in cost (mild stimulation in vitro fertilisation is cheaper), mean that this is becoming an infertility treatment worthy of more consideration.
Whatever the type of preparation you have for IVF, the fertilisation process is generally the same in all methods. There are then different options, depending on whether you have embryos transferred at 2–3 days old or 5–6 days old, and whether you have embryo transfer done immediately or the embryos are frozen and transferred at a future date.
These variations are summarised here, and you can find more detailed information in other articles in this guide by following the relevant links: