Age is a big factor when considering fertility. Contrary to public and cultural beliefs, both males and females have a biological clock. As you age, the quality of the genetic information in a male and female sex cells (or gametes) falls, and as a result of this, there is more chance of infertility, miscarriage and stillbirth in pregnancy and genetic disease and genetic disorders in a child born to elder parents.
However, that's not to say that people cannot get pregnant after the general optimal fertility window. Those practicing good lifestyle habits and healthy may find they can get pregnant at a "later" age. Likewise, access to IVF may also be an option to help people conceive who may be struggling to naturally get pregnant.
What's the Optimum Age to Get Pregnant?
The best age to get pregnant varies between women and men. Women are born with their sex cells (gametes), which are also known as eggs. These hold half the genetic information when then fuses with man's sex cells (sperm) during sexual reproduction. Generally, the best age physically for a woman to get pregnant is during her teenage years. However, women of such ages may not be mentally ready nor fully developed. Hence, there is no "best" age to get pregnant.
In a similar manner, men between the ages of 18 and 40 may find this the optimum time to conceive. The male sperm is made in the Testes under the signal of Testosterone hormone and FSH. Oestrogen and Progesterone are also needed to help the Testes develop and for ejaculation of the sperm in sexual reproduction. However, just as it is with women, there is no specific age to ensure pregnancy. That being said, the sooner the better as with age the quality and quantity of sex cells declines.
How Does Age Affect Fertility?
As you age, the number of eggs a female has falls. Generally speaking, with age the number of eggs within a woman declines. See below:
- Age 14 - 18 there are around 500,000 eggs
- Age 18 - 31 there are around 200,000 - 300,000 eggs
- At age 31 around 100,000 eggs
- At age 35 around 50,000 eggs
- By 40 only 5% or 5,000 eggs may remain
As a woman ages, her levels of key hormones, such as Oestrogen, fall. Consequently, culminating in menopause around the age of 45-52 years of age. However, some women go through menopause early, with some as at 30 years of age, and these women therefore are infertile at an earlier age.
As a man ages, their levels of Testosterone fall and Oestrogen increases, and their sperm count falls. After the age of 40 the sperm count and sperm motility (how easily the sperm can swim up the fallopian tubes of the female to meet the egg in reproduction) also falls.
In both a man and woman, the quality of the genetic information in a gamete decreases as you age. This is because there are more chances for the DNA and RNA which codes for the genetic characteristics of a cell, to become mutated and also there is less DNA repair. Therefore, both the number and genetic quality of sex cells diminishes as you age.
How Is Fertility Tested?
Fertility in women can be tested through various methods. A doctor may perform a pelvic examination or by running hormone tests. The number of eggs a female has can be tested for by testing her FSH, LH, Oestrogen, Testosterone and Progesterone hormone levels, and her AMH (Anti-Mullerian Hormone). In addition, a doctor may also run an ultrasound of the womb to visually identify the number of eggs in the uterus.
Meanwhile, fertility tests for men involve a physical exam and sperm analysis. Semen will be examined for sperm count, how quickly it moves, its size/shape as well as how much fluid is present. A blood test may also be ran to check hormone levels.
What Other Factors Affect Conception?
Conception is the production of a fertile offspring in sexual reproduction. Conception is also affected by medical history, with those with endometriosis, chlamydia, diabetes, fibroids, uterine cysts and other female conditions having high risk of infertility. Chlamydia, erectile dysfunction and low sperm count can also affect a male’s fertility.
Weight status can also affect fertility, with those under and overweight producing either too much or too little dietary and body fat. As Oestrogen and Testosterone sex hormones and Cortisol (stress) hormones are made of fat, too low fat and you have too little Oestrogen and too much and you have Oestrogen Dominance and infertility.
Stress also makes lots of Cortisol be produced and cortisol steals away the fat from the production of Oestrogen and Testosterone, reducing their production and negatively affecting fertility. Dietary Folate (B9 vitamin) and B12, is also needed to make and repair genetic information needed to make new cells such as sex cells, and so low levels of these key vitamins can negatively affect fertility.
It is important to consider all environmental, genetic and lifestyle factors affecting fertility when trying to conceive.