In January this year, the Office Of National Statistics revealed that nearly half of babies are now born to mothers over the age of 30. And infants will soon be more likely to have a mother over 35 than under 25.

Excellent. It would seem that women are now spending their twenties climbing the career ladder, deciding NOT to marry their University sweethearts, and spending too much money on pop-up restaurants... rather than settling for suburbia.

Yet, while this dramatic change in women's baby-making fortunes is a resounding endorsement for growing gender equality, fertility experts are struggling to reconcile positive social change with the biological clock.

According to Dr Geetha Venkat, director of the Harley Street Fertility Clinic, in the past decade she's watched the average age of her patients rise from 30 to 37 years.

And as the average age of childbirth continues to rise (as part of a four-decade long climb) associated problems with having children in later life become more pressing.

When a women enters the doors of a private fertility clinic, it's usually because she already has concerns, Dr Venkat points out. But by the time a woman realises her chances are low, it can be too late.

She suggests that women planning to have children in their mid-thirties should consider checking their fertility levels early on and become familiar with tests that can offer peace of mind, but are not yet offered as standard by the NHS.

Are you aware of these fertility-saving measures?

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  • FSH Test

    While this test of Follicle stimulating hormone (FSH) is an excellent indicator of slowing fertility, Dr Venkay points out that the information often comes “too late” for preventative action. When a woman begins to run out of eggs in her ovaries, the brain makes more FSH hormone in order to stimulate the fertility process. A high FSH reading could indicate that a woman has less chance of conceiving, or reveal <a href="" target="_blank">Premature Ovarian Failure</a>, in younger women.

  • Antral Follicles

    Fertility experts can measure and count these small follicles (2-8mm in diameter) in the womb with ultrasound. When there are fewer antral follicles visible, then it’s likely there are fewer eggs remaining.

  • Thyroxin Tablets

    Low levels of thyroid hormone (also know as hypthyroidism) has been linked to a higher risk of. miscarriage, as this condition makes it difficult for eggs to implant in the uterus. A simple TSH test can diagnose this problem, which affects 1 in 10 women, and treated with thyroxin tablets.

  • Obesity

    Obese women take longer to become pregnant as they don’t ovulate regularly, which leads to a hormone imbalance, explains Dr Venkat. They are also more likely to suffer miscarriages. Conversely, obesity can also be an indicator that a woman has fertility problems. “Polycystic overies occur often in obese women. This is a condition that you're born with and can be treated with medication to correct the hormone imbalance."

  • Smoking

    For women hoping to maintain good fertility levels into later life, quitting smoking is a positive way to start. "Heavy smoking kills off eggs and can lead to women going through the menopause earlier," says Dr Venkat.

Women planning to have children later in life, should also pay attention to their partner's health.

"In one in three cases it’s the man’s fault," explains Dr Venkat. "However, in some cultures, it's hard for men to admit they could have a problems. In my experience, African men are always reluctant to come."

    Baby Making Stats For 2011
  • Nearly half (49%) of all live births were to mothers aged 30 and over.
  • Nearly two-thirds (65%) of fathers were aged 30 and over in 2011 (excluding births registered solely by the mother).
  • 84% of babies were registered by parents who were married, in a civil partnership or cohabiting.
  • The standardised average (mean) age of mothers for all births was 29.7 years.
  • For first births the standardised average (mean) age of mothers was 27.9 years.