Fertility rates have been going down worldwide by about half since 1960, according to data from World Bank.
Many factors including economic growth and changing religious values, are accountable for the drop in birth rates.
But the fact that women are waiting until later in life to try for a baby, is also a contributing factor.
It can be difficult for women to get to where they want in their careers and have children before their biological clock starts ticking.
And while deciding when to have a baby is a deeply personal matter, women who want to have children do need to take their age into consideration, according to top fertility experts.
“Age is a very important factor for a woman trying to conceive. Women, have a finite number of eggs which they are born with and start to lose as soon as they start their first period.”
From a purely biological perspective women are most fertile in their late teens and the odds of a successful pregnancy are the “highest they’ll ever be” during this time.
After this women’s risk of infertility, miscarriage and complications increase gradually until they hit their 30s, and at this time fertility falls more sharply.
“By the time a woman is in her thirties, her ‘ovarian reserve’ is falling and some research suggests that by thirty, the average woman may have used up almost 90% of her eggs, making the chances of a pregnancy less likely,” Dr Harper continued.
However, women of all ages could encounter issues and the medic urges ladies to take care of they bodies by eating well and exercising regularly.
She said: “Older women who have put off starting a family for whatever reason should be prepared for the possibility of encountering issues.
“However, we should remember that that does not mean younger women aren’t susceptible to fertility issues.
“Any woman, at any age, who wants to start a family, should look after her body by eating well and exercising regularly to make sure she doesn’t restrict her chances of pregnancy later on in life.”
How long does it take the average woman to get pregnant? And at what point should a couple seek medical help?
Dr Harper said: “As with all areas of fertility, it entirely depends on the individual.
“If you are healthy and don’t have any known issues with your fertility, it is entirely normal for it to take anything between one month to a year.
“If you’re in your mid to late 30s or older, do bear in mind that it may take you even longer.
“If you’ve been having regular, unprotected sex for a year and leading a healthy lifestyle and are still struggling to conceive, then I would recommend seeking advice from your GP, or sooner if you are over 35.
“The most important thing to remember when trying for a baby is to try and relax.
“Stress and anxiety are known to negatively impact your fertility, so make sure that you and your partner are talking regularly and supporting each other emotionally.”