Female age and fertility
It is still too little known that the fertility of a woman starts to decline after 30 years. This decline accelerates dramatically at an average of 37 years, whereafter fertility is virtually non-existent after 42 years. The menstrual cycle becomes shorter when the woman approaches forty years and gets irregular later on. This biological sequence relates to the diminishing ovarian reserve (stock of eggs), which is some half a million at birth but decreases quite fast, without regenerating the eggs by cell division like men do with their sperm. At an average age of 51 years, the menstruation stops altogether, which is called menopause.
The graph in German shows the sharp bend in fertility at 37 years.
The age indications are average values. It is estimated that one woman in ten gets into menopause earlier, that is at around 45 years. The time lag between the sharp bend of the fertility curve and menopause seems to be pretty constant at 13 years, and has a genetic component. For those women, it is therefore high time to have babies already at 32!
The sharp bend takes place significantly earlier in 10% of women!
We still lack sufficient instruments for early recognition of those women who will develop age-related fertility problems already early in their thirties. The measurement of AMH hormone and counting so-called antral follicles at trans-vaginal ultrasound allow a certain estimate. Often, the problem manifest only at stimulation treatment for IVF, when less eggs develop than expected. However, we have identified risk factors:
Risk factors for premature ovarian ageing |
|
Consequences |
|
Assisted reproduction like IVF does NOT compensate for aged and/or too little eggs!
After the publication by D. Nikolaou and A. Templeton in Human Reproduction 18:1137, 2003.