5 factors that impact your ability to conceive

Experts have identified the five most important factors that can have an impact on your fertility.

Choosing to start a family is exciting and being well informed will give you the best chance of conceiving and having a successful pregnancy. Lifestyle choices can have a significant effect on your fertility and the health of your baby. There

are a numbers of factors that have the potential to boost your fertility and your general health which can be not only confusing but downright scary.

To simplify something that is anything but simple, experts have identified the five most important factors that can have an impact on your fertility.

1) Age

We’re born with all the eggs we will ever have. As we get older, our eggs age too, diminishing in quantity and quality. We can’t control our age but we can sometimes control when we choose to start a family.

The older we get, the longer it takes to conceive and the risk of not falling pregnant increases: at 30, the chance of conceiving each month is about 20 per cent; at 40 it’s around five per cent. The age of the father at the time of conception is also an important factor.

Assisted reproductive methods such as in vitro fertilisation (IVF) can help, but often cannot overcome the effects of age.

2) Weight

Women who are overweight or obese have a reduced chance of getting pregnant.

Obesity can affect fertility by causing hormonal imbalances and problems with ovulation, particularly for obese women having their first baby. If you are overweight and planning to get pregnant, committing to healthy eating and regular exercise is the solution – even losing a few kilos can make a difference. Your partner’s weight can also affect your chances of conceiving.

For those who are overweight, polycystic ovary syndrome (PCOS) is a common cause of infertility. It affects up to one in five women of reproductive age.

One way to measure whether you are overweight is to work out your BMI. You calculate your BMI by dividing your weight in kg by the square of your height in metres – or check out Health Navigator’s BMI calculator. A healthy BMI is considered to be between 18.5 and 24.9.

Having a BMI between 25 and 29.9 is considered ‘overweight’ and a BMI over 30 is considered ‘obese’.

If you’re underweight

Being underweight can also reduce a woman’s fertility because it affects ovulation. Compared to women of a healthy weight, underweight women are more than twice as likely to take more than a year to get pregnant. A BMI under 18.5 is considered underweight.

Need help to gain or lose weight?

Check out the Nutrition Foundation website for lifestyle and dietary advice to help you manage your weight, or find a dietitian near you to create a tailored eating plan.

3) Smoking

Women who smoke or are exposed to other people’s smoke have a higher risk of infertility. Passive smoking is only slightly less harmful to fertility than smoking.

Smoking affects each stage of reproduction, including egg and sperm maturation, hormone production, embryo transport and the uterus. It can also damage the DNA in both eggs and sperm. If you and your partner smoke, quitting together is a great way to boost your fertility.

Need help to quit?

Call Quitline on 0800 778 778.

4) Heavy drinking

Heavy drinking can cause irregular or heavy periods and increase the length of time it takes to get pregnant. New Zealand government guidelines specify no more than two standard drinks a day for healthy women, but if you’re pregnant or planning a pregnancy, not drinking is the safest option.

5) Timing it right

The five days before ovulation through to the day of ovulation is the only time you can get pregnant. These six days are the fertile window in a woman’s cycle. If you have sex six or more days before you ovulate, the chance of pregnancy is virtually zero. If you have sex five days before ovulation, the likelihood of pregnancy is about 10 per cent.

The probability rises until the two days before and including the day of ovulation. At the end of the fertile window, the chance of pregnancy declines rapidly. By 12-24 hours after ovulation, you’re no longer able to get pregnant in that cycle. If you’re unsure when you ovulate, having sex every two to three days will boost your chances of conceiving.

Ask: Dr Emma Parry

Dr Emma Parry is a globally recognised leader in the field of obstetrics, gynaecology and maternal fetal medicine as well as a proud mum of two girls. She is passionate about helping women access better maternity care, which is why she has clinically developed the Lifemum range. Here she answers some key questions.

I am taking a multivitamin with folic acid but my pharmacist mentioned that choline is important. What is it and why is it important when trying to conceive?

A Choline is the new kid on the blockfor pregnancy! It is a small molecule related to the B vitamins and is used in some of the same pathways as folic acid. It also has an important job of transportation of other important active substances. Poor choline intake has been linked to a reduction in cognitive abilities of toddlers and it is becoming increasingly recognised it has a role to play in development of the neural pathways.

In terms of diet, large studies in women with Western diets show that almost 90 per cent will consume less than half the recommended daily intake (RDI) of 450mg. Choline is hard to find in an average diet and the main source is eggs. So if you aren’t a big egg eater a multivitamin with plenty of choline is a great idea! I am lactose intolerant and have excluded dairy from my diet.

Do I need to consider any extra supplements while I’m planning to conceive?

A If you have completely excluded dairy or even if you have reduced your intake significantly you are likely to have a low calcium intake. The recommended daily intake (RDI) of calcium is 1000mg and this is hard to achieve without dairy in your diet so I’d recommend a calcium supplement in addition to your multivitamin as it will have a limited amount of calcium.

In pregnancy calcium is important for the development of the fetus. There is also good evidence to show that calcium supplementation for women with a low calcium intake can support the development of the placenta and reduce the chance of complications. The placenta starts developing at six weeks so it is important to have a good level of calcium at the time of conception.

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