As we all know, fertility declines with age, and the complications that arise are caused by old eggs. In older women, eggs are more likely to divide abnormally prior to fertilisation which can lead to an incorrect number of chromosomes in the resulting embryo. This is called aneuploidy and may lead to miscarriage or chromosomal abnormalities such as Downs Syndrome.
Ideally a young woman should start thinking about her reproductive window in her 20s and make a plan for her future fertility. Assessing your ovarian reserve and the length of time you are likely to produce healthy eggs can be done with a blood test called the AMH (anti-mullerian hormone). Age at menopause has some familial concordance so finding out when your mother went through menopause is also important.
If a woman wants to extend her reproductive window, the technology is available to retrieve and freeze a woman’s eggs for up to ten years. Cryogenics has been used to freeze embryos for many years now and is an integral part of the IVF (in-vitro fertilisation) process. Fertility Associates who have clinics in Remuera and at Apollo Drive have now had 35 successful pregnancies in women who have used their own frozen eggs.
Age is still a factor when considering egg freezing as a 36 year old woman has a 50% chance of having a child if she collects and freezes ten eggs but a 39 year old woman would need to freeze 16 to have the same chance.
Protecting your eggs before and during your reproductive years includes all the usual lifestyle advice like avoiding smoking cigarettes, eating a healthy diet and doing regular exercise. There is now increasing emphasis on avoiding environmental chemicals like phthalates and parabens in cosmetics as well as BPA and pesticides.
Fertility specialists are unlikely to recommend a long list of expensive supplements but there is emerging evidence that co-enzyme Q10 may be useful. It is thought to improve mitochondrial function, and in mice has been shown to increase the likelihood of a live birth following IVF.
Conception: Reproductive Carrier Screening
Many women and couples are unaware that testing is available to assess the risk of having a baby with a genetic disease. These tests are not free but are reasonably easy to access and should be considered prior to conception or in early pregnancy. Genetic diseases that are inherited in an autosomally-recessive pattern (an abnormal gene from both parents required for the condition to be expressed) often occur without a known family history.
The three most common conditions that occur in New Zealand are:
- Cystic Fibrosis: A disease affecting the lungs and digestive tract with a life expectancy reduced to the late 40s. One in 25 Europeans are carriers and if both parents carry the abnormal gene, their chance of having an affected child is one in four.
- Spinal Muscular Atrophy: Type 1 usually results in death before the age of two years old. One in 40 are carriers.
- Fragile X: The most common cause of inherited intellectual disability. One in 250 women are carriers.
This testing could lead to further diagnostic investigations during pregnancy such as an amniocentesis, or cause couples to consider IVF in order to have pre-implantation genetic testing of an embryo.
If there is a known family history of an inherited disease, then a fully-funded assessment and subsequent counselling is offered by the Genetic Health Service NZ.
Dr Michaela Wood