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Understanding your fertility

Age, weight, your health, and medical history can affect your fertility. Knowing your chances early can help you get pregnant more easily.

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Being informed

Getting to know a bit more about how your body works and how hormones work will help you.

There are many reasons why people may have issues conceiving. Age is probably the most important factor of all. For example, a woman aged 35 has about a 15% chance of conceiving each month, which by the age of 40 has dropped to approximately 5% each month.

General health also has a part to play, such as being fit, being at your ideal body weight, and eating well. Previous and existing health conditions might also have influence on your ability to conceive. Regardless of this, some people will still experience unexplained infertility which, though difficult to understand, can still have good outcomes with fertility treatment.

If you have been trying to conceive and it is not happening as you expected, you are not alone.

Latest research shows that up to 25% of us experience some kind of infertility when trying for a baby. The good news is that you are in the right place to take the first step. Our dedicated team of highly experienced doctors and scientists deliver world-leading fertility treatments and personalised care to give you the best chance towards starting a family.

The best thing you can do is talk to us.

Seeking fertility information is one of the best things you can do – and if you need more clarity or are feeling worried for any reason, having an appointment with one of our fertility doctors is the best option.

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Age

How age affects fertility is the most important factor when having a baby. Young women without fertility problems have about a 25% chance per month of having a baby naturally if they try at the right time of the month. This falls to about 12% at age 37 and 5% at 42. Today, more women than ever over 40 are wanting to have their first child. It is possible, but the older you are, the more likely you are to need help. To work out your chances visit our biological clock.

How long should I wait before seeking help?

Understanding how long you should wait before seeking help is really important. 

The online Biological Clock can tell you how long to try naturally, before seeking help. Put in your age and how long you have been trying and the Biological Clock will tell you when you should be seeking help. Have you got time to wait? 

If you’re in your late 30s and haven’t been able to conceive after six months of trying, then it’s time to seek assistance and explore your options.

What can I do to boost my fertility?

There are a few things you can do to help your fertility along - sometimes small but important changes you can make to boost your fertility. Eating well to maintain a healthy BMI, stopping smoking, and minimising alcohol are just some of these. Did you know that 50% of fertility factors are male and 50% female? Our boosting fertility page has lots of useful tips for both women and men – as fertility issues can stem from either partner.

Eating well to maintain a healthy BMI, stopping smoking, and minimising alcohol are just some things you can do to boost your chances of pregnancy. Have a look at our boosting fertility page with lots of useful tips for everyone - remember, fertility issues can stem from either partner. 

Fertility timeframe: there is a fertility test that estimates ovarian reserve called the Anti-Mullerian Hormone (AMH) fertility test. This test can help predict how many eggs we are likely to be able to obtain during an IVF cycle and it can help identify those who may experience early menopause. Like most tests, reading AMH results takes in a number of variables, so it's useful to have the help of a fertility specialist to interpret the results. Talk to us (or your GP) about arranging your test.

Get to know more:

BMI calculator

Biological clock calculator

Anti-Mullerian Hormone (AMH) fertility test

Fertility Language

Fertility Associates offers you the best chance

Fertility Associates has assisted in the successful conception of over 29,000 babies since 1987 – that’s the equivalent of one child in every classroom in New Zealand.  We are committed to providing you the best possible treatment with your individual plan together with specialised personal care to get you pregnant!

If you have questions about your fertility but are not quite ready to seek specialist help we also offer a free 15 minute confidential telephone consultation with an experienced fertility nurse. It’s easy to take the first step - just book your free nurse consultation through our website, or visit one of our specialised clinics located throughout the country. Give yourself the very best chance with Fertility Associates. Contact us today 0800 10 28 28.

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Related reading

Ready to start your fertility journey?

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The Biological Clock

This tool indicates:

  • Natural conception per month if you have no fertility issues
  • IVF success rate at the same age
  • When to seek help after months of unsuccessful attempts

If you are concerned at any stage – we recommend booking a doctor appointment or a free nurse consultation. The sooner you make a plan the better your chances in the long term.

When to seek advice early

  • If you have polycystic ovaries, endometriosis, or have been through a cancer diagnosis; we recommend you get in touch quickly so we can talk you through all your options and give you the greatest possible chance of success.
  • If you’re a single woman considering motherhood in the future; it’s best to approach us early and consider egg freezing as this can be an option for you while you have a higher ovarian reserve and healthier eggs.
Set your age and the months you’ve been trying to conceive
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Your chance of having a baby per month for fertile couples
Your chance of having a baby per IVF cycle (if experiencing infertility)

Body Mass Index calculator

Being overweight or underweight can reduce fertility, so it is important to keep your body weight within the normal healthy range.

Body Mass Index (BMI) is an indication of your body weight and can be calculated by dividing weight by height. You should aim for a BMI of between 20 and 25, as this will optimise your chances of conception.

Woman’s BMI below 19

Even in these modern times, nature knows best. If a woman's BMI falls below 19, the body senses famine and ovulation is switched off to prevent the risk of having a baby with malnutrition. Excessive exercise can reduce body fat and increase muscle mass to a point where periods cease for the same reason. Risk of miscarriage is also increased in women with a low BMI.

Being underweight

If a woman's BMI falls below 19, the body senses famine and ovulation is switched off to prevent the risk of having a baby with malnutrition. Excessive exercise can reduce body fat and increase muscle mass to a point where periods cease for the same reason. Risk of miscarriage is also increased in women with a low BMI.

BMI’s greater than 30

This can reduce fertility by 50%. Pregnancy for women with a 30+ BMI is often associated with problems such as maternal diabetes, high blood pressure, big babies and increased risk of caesarean section.

Add your height and weight to calculate your BMI