The modern way of life, studies and professional recognition drive women into postponing the creation of a family. On Mother’s Day celebration, we would like to inform you about the effects of age on female fertility.
Human fertility, especially female fertility, declines dramatically in an age-dependent manner, mainly due to the decline of both quality and quantity of the oocyte and follicle pool with increasing maternal age. The proportion of oocytes with abnormal chromosomes also increases with maternal aging, which is a major factor causing aneuploid formation in the resulting embryos. Embryonic aneuploidy is also a major cause of failed embryo implantation and miscarriage; hence aneuploidy is considered to be one of the most important factors causing the low efficiency of in vitro fertilization (IVF) treatments.
The average age of menopause is about 51 years and this marks the absolute end of fertility but in fact, it is rare for a woman to conceiveς within 10 years prior to menopause. In part this is because the quality of the eggs that are released is compromised; at age 40 about 75% of eggs are chromosomally abnormal which reduces the chance of pregnancy and increases the risk of miscarriage. While many women in their late thirties and early to forties give birth to healthy babies, it is an undisputable fact that increasing age (beyond age 35) reduces a woman’s likelihood of conceiving and giving birth. Here are some facts about the relationship between female age and fertility:
• the monthly chance of conception decreases from 20% for women aged 30 to 5% for women aged 40
• the risk of chromosomal abnormalities in the fetus increases from 1 in 385 in women aged 30, to 1 in 179 in women aged 35, to 1 in 63 in women aged 40 and at age 45 in 1 to 19
• less than 10% of women in their early twenties experience pregnancy loss compared with more than 50% of women aged 42 or more.
Age and IVF success
IVF can help people with fertility issues have a family but the technology cannot make up for the natural decline in fertility that happens as women get older. As female fertility decreases over the years, the same rates of pregnancy-assisted reproduction are also reduced. From the age of 31 to 34, the couple’s success rates are reduced by 3% for each passing year. From the age of 35 to the age of 39, the reduction in pregnancy each year is 8%. From 40 to 42, 15% for each year and from 42 and then percentages are very low.
These data are about women who use their own eggs. If an older woman uses donated eggs from a younger donor, her chance is the same as that of a woman in the donor’s age group.
• Deatsman S., Vasilopoulos T., Rhoton-Vlasak A., Age and Fertility: A Study on Patient Awareness. JBRA Assist Reprod. 2016 Jul-Sep
• Edgardo S., Alessio Paffoni A., Busnelli F., et all. Age-related infertility and unexplained infertility: an intricate clinical dilemma. Human Reproduction, Vol. 31, July 2016.
Biologist MSc, PhD