Imagine your child has been born prematurely and urgently requires a life saving incubator. Two units are wheeled into the room and you’re given a choice. A brand new model or the one with a forty year old date stamp barely visible through it’s dust covered glass. No prizes for guessing which you’ll select and yet, when it comes to creating new life, we often willingly opt for the dusty unit. This choice holds serious consequences for the fetus and its development.
A lot has been written on the ideal ages of the mother and father for producing the perfect offspring, one that will be blessed with the best on offer from both parents. There isn’t wholesale agreement on the topic, but as a basic guide the following combination of parental ages are considered to be ideal for the production of Superbaby.
A father between the ages of 27 and 30 years of age and a mother between the ages of 18 and 20
Hardly typical of the current trend in most Western countries, where women now delay conception, for various reasons, often into their late thirties and forties. Careers, financial constraints, education and various other factors influence their decision . There is strong data and evidence to suggest this tendency is contributing to increased levels of genetic abnormalities and compromises the fetuses chance of normal development.
We’ll examine the female’s role in this cycle first and then look at the male.
The Dusty Incubator
If we place emotion to the side and view the female body purely from a biological point of view, then the analogy of the two incubators can be applied to the female womb and reproductive system. Age deteriorates the optimal operating conditions of this unit. Typically ready for production at the age of 13, the womb reaches optimal operating capacity five years later.
At 18, the female body is in the best physical condition it will ever achieve and each year thereafter, its condition declines. Its not just the unit, but the body supporting it that is subject to the degenerative effects of aging. Most importantly, and key to the whole process of creating life, is the woman’s ability to produce healthy eggs.
Our bodies don’t believe in the principal of saving the best for last and no where is this more pronounced than in the way the female reproductive cycle works.
Mommy Egg’s Life Cycle
At birth, the normal female ovary contains about 1–2 million/oocytes (eggs). Females are not capable of making new eggs. There is a continuous decline in the total number of eggs each month. By the time a girl enters puberty, only about 25% of her lifetime total egg pool remains, around 300,000. Over the next 30–40 years, her entire egg supply will be depleted.
Although we cannot know with absolute certainty how many eggs remain within the ovaries at any given time, most women experience a significant decrease in fertility (the ability to conceive a child) around the age of 37. At the time of menopause, virtually no eggs remain.
The large supplies of eggs within each ovary are immature (primordial), and must undergo growth and maturation each month. The eggs are stored within follicles in the ovary. During a woman’s lifespan, large numbers of follicles and oocytes will be recruited to begin the growth and maturation process. The large majority, however, will not reach full maturity. Most die off in a process called atresia. Only about 300–500 of these eggs will mature over a women’s life span.
The maturation of eggs typically takes about 14 days and can be divided into 2 phases. During the initial period as many as 1000 eggs begin to develop and mature. The second phase requires gonadal hormone stimulation to stimulate further development. Even though hundreds of eggs have begun to mature, most often only one egg will become dominant during each menstrual cycle, and reach its’ fully mature state, capable of ovulation and fertilization.
The remaining eggs/follicles will wither and die. Pre-pubertal girls do not produce the gonadal hormones necessary for the second phase of development, so the many eggs that started to mature will simply wither away. The large number of eggs that are used each month account for the steady decline in the female’s total egg pool that occurs from birth to menopause.
The question we need to address is the following. Is there a difference in quality between the 20 year old females matured egg and that produced by a 30 or 40 year old? The definitive answer to that is yes. Age is the number one factor that influences the quality of a woman’s eggs.
The age related decrease in quality has a proportionate influence on the risks posed to the embryo or developing fetus. Poor egg quality is closely associated with chromosomal abnormalities in embryos, also known as aneuploidy. The take away from this is the following. To decrease age related risks to the fetus, conceive early.
Its important to mention that age isn’t the only factor that can influence egg quality. Poor life choices, dietary intake, drug abuse, alcoholism, prescribed medication and other factors influence the quality of eggs in young women. Couple these life choices with age and the risks are multiplied.
The mother’s physical condition
Women who choose to conceive in later life are faced with a number of challenges their younger versions manage to evade. The entire process, from conception to delivery, is a walk in the park for young women. Their physiology is in its prime and everything usually works without complication. Women in their thirties and forties aren’t this fortunate.
Older women (30+) have a higher risk of having gestational diabetes, placenta prevail, placental abruption, preeclampsia, a still birth or miscarriage. These risks increase exponentially with age and factors such as high blood pressure, endometriosis, polycystic ovary syndrome and other age related conditions can seriously impact an older woman’s odds of conception or producing a health baby.
Daddy Sperm’s Life Cycle
Now we know how age influences things from a female perspective, lets examine the male’s role in the creation of life. Unlike women, men don’t produce a limited number of sperm cells. At 102, little else might work, but the man can still sire a child. Our question then, is does age also affect the quality of sperm?
Men younger than 40 have a better chance of fathering a child than those older than 40. The quality of the sperm men produce seems to decline as they get older.
Most men make millions of new sperm every day, but men older than 40 have fewer healthy sperm than younger men. The amount of semen (the fluid that contains sperm) and sperm motility (ability to move towards an egg) decrease continually between the ages of 20 and 80. The risk of miscarriage is higher for women whose male partner is older than 45 , compared to men younger than 25 years of age. This speaks directly to the quality of the sperm produced as men age.
Building those Babies
While it is true that many women in their thirties and even into their forties have healthy pregnancies and babies, the fact remains that many struggle to conceive after the age of thirty. This article isn’t about conception though, it is about advocating the benefits of conception before the age of thirty, not for your sake, but for your baby’s.
Because of the changes that happen in eggs and sperm as we age, including damage to genetic material, children of older parents have a slightly higher risk of birth defects and genetic abnormalities. The risk of mental health problems and autism spectrum disorder is marginally higher in children of fathers older than 40 than in those with younger fathers.
It is estimated that the risk of having a baby with a chromosomal (or genetic) abnormality is approximately one in 400 for a woman aged 30 and one in 100 for a woman aged 40. That risk alone should be sufficient to give people pause for thought. Our desire for a family cannot outweigh the risks posed to our unborn children.
The risks of miscarriage and complications in pregnancy and childbirth are higher for older women than for younger women, and the risk of miscarriage is further increased by the age of the father.
What about IVF and freezing eggs or embryo’s
If eggs are harvested before the age of thirty you dramatically increase your chances of a viable pregnancy. There are however no guarantees and to revert to our dusty incubator analogy, implanting the fertilized egg into a less than perfect growth environment (an older womb) increases the risk that something could go wrong.
Your partner will in theory have aged with you and it is therefore wise to have sperm frozen at the time your eggs are harvested, unless you opt for the choice of freezing a fertilized egg or embryo.. Its a simple step that reduces the risks associated with the process of fertilizing the eggs later.
In Australia for instance, the chance of a live birth from one complete IVF cycle (which includes all fresh and frozen-thawed embryo transfers following one ovarian stimulation) is about:
- 43% for women aged 30 to 34 years
- 31% for women aged 35 to 39 years
- 11% for women aged 40 to 44 years.
For older women the chance of having a baby increases if they use eggs donated by a younger woman.
With typical IVF, where eggs are removed, fertilized and then implanted again within days, the whole process is made proportionately more difficult by the age of the mother. The older the womb, the less likely the implanted egg’s chances of survival.
