The time it takes to conceive varies from couple to couple – around 84% of couples will conceive naturally within one year if they have regular unprotected sex. For couples who’ve been trying to conceive for more than three years without success, the likelihood of pregnancy occurring within the next year is 25% or less.

If you haven’t conceived within one year of trying, you can also read our blog, 5 Reasons Why You Might Not Be Getting Pregnant. Anyone who is made aware they may have fertility problems should see their GP at the earliest convenience, who will be able to provide more information on the available treatment options, such as IVF.

The Human Fertilisation & Embryology Authority (HFEA) presents IVF success rates for every licensed fertility clinic.

Success rates show the number of treatments carried out by the clinic in a particular year and the number of pregnancies or live births that were born as a result. The success results published by HFEA for each clinic can be viewed online – they should only be used as a general guide. The majority of clinics’ success rates are around the national average:

  • 38% for women under 35
  • 33% for women between 35-37
  • 25% for women between 38-39
  • 19% for women aged 40-42
  • 8% for women aged between 43-44
  • 3% for women aged 45 and over 

All of the above statistics are for IVF using fresh embryo's and the patient's own eggs.

Success rates will differ between clinics due to the type of patients a clinic treats (age being one factor), the type of treatment carried out and the clinic’s treatment practices.

In March 2016, HFEA posted an update on its website which stated that the success of IVF has continued to rise with birth rates increasing to 26.5% in 2013 from 25.9% the year before.

Success factors of IVF


Your age, and therefore the quality of your eggs, is an important factor when it comes to the success rate of IVF. Being older with fewer eggs of a lower quality can reduce the chances of IVF success. The live birth rate for women under 35 who start on IVF cycle is 40% whilst women over the age of 42 have a 4% success rate.

Type of fertility problem

IVF success also depends on the type of fertility problem. Male infertility problems like uterine abnormalities or fibroid tumours or exposure to DES are likely to decrease the success of IVF treatment.

Ovarian dysfunction, including high FSH levels which indicate a low ovarian reserve, may reduce the chances of IVF success.

The length of time you and/or your partner have been infertile is another factor to consider as the chances of IVF success decrease the longer a couple has been infertile.

Donor eggs

Using donor eggs from a younger woman might increase the chances of pregnancy for women over 40.


Women must stop smoking at least three months prior to IVF treatment. Smokers generally require higher dosages of fertility drugs to stimulate their ovaries, have lower implantation rates, require twice as many IVF attempts and experience more failed fertilisation cycles.

Women who are overweight have an increased risk of infertility as well as miscarriage. Overweight women also have less success with IVF fertility treatments, so it’s important to stay within a healthy weight range.

Previous pregnancy

If you’ve previously been pregnant with the same partner, there’s a greater probability of IVF success.

The Hewitt Fertility Centre has a 40% clinical pregnancy rate and provides 3,800 treatments per year – visit our success stories page to find out exactly how we’ve changed the lives of many couples across the country.

Mr Andrew Drakeley Andrew Drakeley

Mr Andrew Drakeley is the Clinical Director at the Hewitt Fertility Centre, working principally at the Liverpool Women’s site but with managerial responsibility for Knutsford.

Other Recent News