Many women nowadays have been on the pill since their teens and don't come off it until their 30s when they decide to have a baby," she explains. "So there may be underlying fertility factors that they aren't aware of"
Fertility and pregnancy expert, Zita West, has revealed that many women start to get worried if they don't become pregnant quickly once they've decided they want children. But this worrying in itself can affect fertility levels.
There are many other factors that can influence a woman's likelihood of getting pregnant, says West, but the main one is age.
It can take longer the older you are," she says.
According to Professor Geeta Nargund, medical director for Create Fertility, a woman’s "best reproductive years" are in her 20s. When a woman reaches her thirties, her fertility will gradually decline, particularly after the age of 35".
"Each month that she tries, a healthy, fertile 30-year-old woman has a 20% chance of getting pregnant," Nargund said.
West added that lack of fertility awareness when it comes to sex and understanding ovulation; mindset, which when dealing with uncertainty can be really significant; and lifestyle choices.
In regards to the latter, the effects of alcohol, smoking, drugs and weight are well documented, and there can also be issues with medications such as painkillers and anti-inflammatories, which can also deplete the body of nutrients needed for fertility.
West also flagged up that long term use of the contraceptive pill can hide underlying fertility issues.
"Many women nowadays have been on the pill since their teens and don't come off it until their 30s when they decide to have a baby," she explains. "So there may be underlying fertility factors that they aren't aware of".
However, that isn't to say that the pill or any other method of reversible contraception causes infertility, as Halil explains:
"When you stop using contraception your periods and fertility will return to normal, though sometimes ovulation can be delayed or be irregular for a short time after stopping hormonal contraception," she added.
"If you use the contraceptive injection, your periods and fertility may take longer to return to normal than after other methods of contraception".
If after 12 months of having unprotected sex, you haven't conceived then all Halil, West and Nargund agree it's best to contact your GP.