Career women who put "fun first, motherhood later" are finding they are in a race against time if they are to achieve their parenting dreams. Health Reporter Emma Brady had an ovarian reserve test to discover if she, like thousands of other women, may have left it too late...
When my trainer at the gym told me I had the body of a 27-year-old, I was flattered, although I suspected it was a cheap chat-up line.
Less than two weeks later I am sitting in a consultation room at a fertility clinic being told my biological age is 37. I am actually 34.
Despite my hedonistic lifestyle while at university, I had always been careful to avoid any drunken 'mishaps', unaware my smoking and drinking may be doing more damage than any unplanned pregnancy.
Like thousands of women across the country I chose to pursue a career which required study, long hours and commitment - all of which I was, and am, happy to give.
Not once during my 20s did the idea of motherhood trouble me, until my god-daughter Leah was born in August 2000.
Since then I could hear the incessant tick-tock of my biological clock and that has grown so loud, it's almost deafening.
Having overseen The Post's Funded Fertility Treatment For All campaign, I had become acutely aware of how fragile fertility is.
But how can that be when 21 of the 25 countries with the world's lowest fertility levels are in Europe, yet conversely Britain has one of the highest rates of teenage pregnancy in the EU?
So when I went for a blood test and ultrasound scan at Midland Fertility Services (MFS) in Aldridge, Walsall, I did think my healthy lifestyle would be my saviour, not realising I was falling into the same trap as so many other would-be parents believing everything would be fine.
But here's a reality check: one in five women will never give birth, fewer women in their 20s are giving birth while the number of 40-something first-time mothers has almost doubled.
And when the scan revealed no serious problems, I was convinced I would be fine, despite the fact I had mistimed the blood tests.
Now as I stare at the results in front of me, it is clear the writing is on the wall. My time is now, and if not now, my only option is to put motherhood on ice by freezing some eggs.
No woman wants to hear they look any older than they are but I was shocked by the doctor's response to my test results.
While levels of follicle stimulation hormone (FSH) and lutinising hormone (LH) were within the normal range of less than 8, the FSH was 7.8 while LH was recorded as 4.3, which suggested my body was working nearly twice as hard to release one egg a month.
Both results for Inhibin B - which is vital for determining a woman's fertility level - and Anti-Mullerian Hormone (AMH) were both below normal levels.
Dr Abey Eapen, a clinical research fellow at MFS, said: "You are two to three years older biologically than your actual age, so I wouldn't advise you to leave it any longer if you want to start a family.
"However if you're not in a suitable situation you may want to look into egg freezing.
"You are certainly not alone, I would say about ten to 15 per cent of women aged 30 to 34 who have the ovarian reserve test produce similar, if not more acute, results.
"If you are serious about having a baby, there's no time to wait."
So what had caused this somewhat premature slump in my fertility? Was it years of 'social smoking' that affected my ovaries, causing them to shrink? Or had the loss of more than 20lbs (4kg) since I began marathon training in 2005 been my undoing?
I currently run 30-40 miles a week and eat very healthily, yet my body fat-to-muscle ratio is "perilously low".
Dr Gillian Lockwood, the clinic's medical director, added: "The body needs fat, in particular cholesterol, to produce oestrogen and to protect nerve endings. So in a way your marathon training and your fertility levels are at odds with each other.
"These results do put you on on the wrong side of the 35 divide, at about 36 or 37, so if and when you decide to start a family of your own, if nothing much happens in six to nine months it would be worth getting your partner checked.
"However if you feel the chance of being a biological mother is important to your life plan, getting some eggs frozen would be a responsible thing to do."
Women in the 21st century are able to benefit from medical 'miracles' that could not exist five or even ten years ago, so I am not without hope but I do not want to become another statistic. I do not want to be the one-in-five who never gives birth.