Whether a woman conceives naturally or with fertility treatment, her chances of achieving a pregnancy decrease with age. By comparing pregnancy success rates between IVF patients using their own eggs, and patients of the same age using donor eggs, it was found that the age of the eggs used were the determining factor in achieving pregnancy. For example, a forty-year-old woman using the eggs of a twenty-five-year-old donor, has the same chance of conceiving as that of a twenty-five-year-old woman using her own eggs.
It is recognised that the chances of miscarriage also increase with the woman’s age, and this is thought to be due to genetic changes relating to the age of the egg. Those women using younger donor eggs have a reduced risk of miscarriage and therefore a greater chance of delivering a healthy baby.
High FSH (follicle stimulating hormone)
In women with normal menstrual periods, apart from age, the second most important factor that affects IVF outcome is the number of eggs collected. This is determined by the ovarian reserve (the number of potential eggs available in the ovary) which is commonly measured by checking FSH and Oestradiol levels, ultrasound scans and/or Anti-Müllerian Hormone (AMH). Women with low FSH or low AMH tend to produce a smaller number of eggs.
Women with reduced ovarian reserve have a lower (but reasonable) chance of achieving a live birth. We therefore offer IVF to these women with regular periods and provide them with a realistic understanding of their chances of pregnancy.
Women with periods do not benefit from repeated FSH testing as we believe that once FSH is high, it denotes reduced ovarian reserve and our recommendation is that IVF treatment commences sooner rather than later.
The Lister Fertility Clinic has wide experience in treating women in this category.
Embryo quality
Embryo quality and embryo selection are one of the most important factors determining the outcome of a treatment cycle. Pregnancy is more likely where there are four or more embryos from which we select the best embryo(s) for transfer. Embryos that are either slow to develop or highly fragmented may be less likely to implant.
Duration of infertility
Studies have shown that women with a long history of infertility have a reduced chance of conception following treatment and this becomes significant when the length of time is 10 years or more. This is not true however, in women who have had a baby before. Here, the length of infertility appears to make no difference to the outcome.
Cause of infertility
In general the cause of infertility does not influence the outcome of IVF treatment.
There is evidence however, that the presence of a hydrosalpinx (fluid in a fallopian tube) may impede implantation and should be removed prior to treatment
Similarily, submucous fibroids in the uterine cavity may also affect implantation and it is recommended that these are removed surgically prior to treatment.
As severe male infertility can now be treated with the introduction of the ICSI procedure, this does not affect the outcome of treatment. The pregnancy rate for ICSI is similar to that following IVF treatment.
