Stephanie Francis Wednesday 5 September 2012 10:52am

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7 things you didn’t know about fertility.

It is National Fertility Week! Doesn’t that sound like a good time. Is there an egg and sperm logo? There should be, dammit.

To celebrate, we sat down with Ms Stephanie Francis from the Fertility Coalition and asked her to tell us everything we might not know.

by STEPHANIE FRANCIS

1.     This is when to have sex if you want to get pregnant

Two thirds of Australian men and women who have responded to surveys, didn’t know when in a woman’s cycle they should have sex if they wanted to conceive.

So, if you’re among the two thirds, the most fertile time in a woman’s cycle is the two days leading up to ovulation and the day of ovulation. You calculate your ovulation day by subtracting 14 days from the estimated start of your next period (so you need to know the average length of your cycle). If you have a 28-day cycle, your most fertile time would be days 12-14. You can find an ovulation calculator at www.yourfertility.org.au

2.     Being overweight can affect your chances of getting pregnant

Women who are overweight or obese have less chance overall of getting pregnant than women of a healthy weight (with ‘healthy’ defined as having a body mass index – or BMI – of between 20 and 25). Overweight and obese women are also more likely to take longer than a year to conceive.

Being obese (BMI of more than 30) can cause pregnancy and birth complications, such as hypertension and pre-eclampsia. Being overweight or obese in pregnancy also has implications for your baby’s health later on, as children born to overweight or obese mothers are more likely to become obese children and adults – with associated health problems (including fertility issues). The good news is that if you’re overweight or obese and planning to try for a baby, losing even a few kilos can increase your chances of getting pregnant.

3.     A man’s weight can affect his fertility

Overweight and obese men have worse sperm quality than men of healthy weight. Being overweight or obese can also cause hormonal changes in men that reduce fertility and make them less interested in sex. Men who are very overweight are also more likely to have problems getting an erection. Taken together, all these factors add up to less chance of a man who is overweight or obese fathering a child.

4.     Smoking women reach menopause earlier than non-smoking women.

They also find it harder to get pregnant, with women who smoke at least 1.5 times more likely than non-smokers to take more than a year to get pregnant. The good news is that if you stop smoking, it’s estimated that the effects on fertility are reversed within a year.

5.     Passive smoking can affect a woman’s ability to get pregnant.

Women who live with a smoker are more likely than those in non-smoking homes to take longer than a year to get pregnant.

6.     Women don’t have forever to have a baby (hello guys!)

The Your Fertility campaign survey found that a massive 60 per cent of men thought women’s fertility started to decline after 40. Nearly 30 per cent of them thought women’s fertility starts to drop post-50. Guys, here’s the deal: a woman’s fertility starts to decline in the early 30s and declines more rapidly after 35. A woman is born with all the eggs she is going to have in her lifetime, so as she ages, these drop away or deteriorate. By age 40, a woman’s fertility has fallen by half.

Five Fertility Factors – Timing from VARTA on Vimeo.

7.     A guy’s age matters, too.

Guys have more time on their side but their fertility, too, declines with age. For men, fertility starts to drop in the 40s. All other things being equal, the time to pregnancy if a father is over 40 is two years (compared to 4.5 months if a man’s under 25).

Also, as a man ages, the risk of him fathering a child with a developmental disorder, such as autism, increases. Children with fathers aged 40 or older are at least five times more likely to have an autism spectrum disorder than children of fathers aged under 30.

The risk of miscarriage is twice as high among women whose male partner is aged over 45 than among those whose partners are under 25. The take-home message here is that if you want a baby and you’re in a position to have one, you might want to consider your age and that of your partner in deciding when to start a family.

Visit the Your Fertility website at www.yourfertility.org.au for more independent, evidence-based information about fertility, brought to you by the Fertility Coalition.

Stephanie Francis is communications manager at the Victorian Assisted Reproductive Treatment Authority, lead agency of the Fertility Coalition.

What have your experiences or your friends’ and families’ been in trying to get pregnant?