There are about six days in a woman's menstrual cycle when pregnancy is possible

Days when pregnancy is possible are what’s known as a woman’s ‘fertile window’. Exactly when these days occur in a menstrual cycle depends on how long the cycle is – and this can vary a lot among women.

These days of the fertile window include the day of ovulation (when an egg is released from an ovary). Pregnancy is possible if you have sex (intercourse) on these days.

Day of cycle Stage Fertility
1-7 Menstruation Least fertile stage
8-9 Post-menstruation Possible to conceive
10-14 Days around ovulation Most fertile
15-16 Post-ovulation Possible to conceive
17-28 Thickening of uterine lining Less fertile unlikely to conceive

When it comes to age and fertility, it is the combination of both partners' ages that determines the likelihood of pregnancy.

Many of us know that a woman’s age is the most important factor affecting her fertility, but a man’s age also plays a part in the odds of achieving a healthy pregnancy. Research shows that men younger than 40 have a better chance of fathering a child than those older than 40, and this is likely due to sperm quality decreasing with age.A woman’s fertility starts to slowly decline in her early 30s and speeds up at about the age of 35, with a decline in egg quality.

For couples trying to get pregnant when the woman is aged 35 or younger, their monthly chance of getting pregnant is about 20%, or one in five. By age 40, the chance of pregnancy is about 5% each month.

The male partner's weight can affect a couple's ability to have a baby.

For both men and women, being a healthy weight can increase the chance of pregnancy and having a healthy baby. Study shows that men who are overweight or obese have poorer sperm quality and are not as fertile as men of a healthy weight. For women, being overweight – or underweight – can impact hormone levels, the menstrual cycle and the quality of eggs.

Healthy eating, regular exercise and losing even just a few extra kilos can boost both male and female fertility.

A woman's caffeine intake may impact how long it takes to get pregnant.

The research is not entirely clear on this topic, but several studies have shown that women who consume large amounts of caffeine may take longer to become pregnant and may have a higher risk of miscarriage.

Caffeine can be found in varying amounts in coffee, black and green tea, energy drinks, chocolate and some soft drinks such as cola.

It is recommended that women limit their caffeine intake to 200mg per day (about two cups of coffee) if they are pregnant or trying to get pregnant.

STIs (sexually transmissible infections) can damage the reproductive organs and cause infertility.

If left untreated, STIs such as chlamydia and gonorrhoea can go on to cause reproductive complications such as pelvic inflammatory disease (PID), which can cause fallopian tube blockage that can lead to infertility. These STIs can also affect male fertility if left untreated. They can harm sperm quality and cause damage to the male tubes. What’s more, chlamydia and gonorrhoea often have no symptoms – or the symptoms are mistaken for something else – and people may not even know they are infected and/or endangering others.

The good news is, these STIs are easily diagnosed and treated by your doctor, so it’s important to have routine STI screenings and always practise safer sex.

IVF treatment cannot overcome age-related infertility.

Many people believe that IVF is a good back-up option for having children at a later age. However, this is not the case when it comes to couples using their own eggs and sperm. The technology of IVF cannot make up for the natural decrease in fertility that comes with age. For couples having IVF, the chances of having a baby are higher if the woman is younger than 35 years of age and decreases significantly after 40 years of age. The chance of having a baby after one IVF cycle for women aged between 40 and 44 is only about 5%.

On the male side of the equation, the chance of having a baby with IVF is higher if the man is younger than 41 years of age.

Even if you have already had one baby, it does not mean you can easily have another.

If a woman has already had one or two children and wants a second or third child, her age at that time is the most important factor in determining the chance of that happening.

So, if a woman is 37 when she has her first child and then tries for a second child when she is 40, the monthly chance of getting pregnant is still the same as a 40-year-old who has not yet had a child – only 5%.

Sperm don't act alone in the journey towards reaching the egg.

While sperm need to be strong swimmers in order to reach the end-goal of the egg, they are by no means acting alone in their mission.

In fact, a good portion of a sperm’s journey is helped along by the woman’s muscles in her uterus (womb), which naturally tense and relax to gently coax the sperm along the fallopian tubes towards the egg. What teamwork!

Overall good health isn't necessarily a sign that you (or your partner, for that matter) are fertile.

You exercise regularly, eat a nutritious diet, and have enviable cholesterol and blood pressure levels. That’s great, but it doesn’t mean you’re fertile. One in 10 healthy couples of reproductive age will experience fertility problems. The causes are variable and equally attributed one-third of the time to the female, one-third of the time to the male, and one-third to unidentifiable reasons or to both partners. Unfortunately, the biggest factor that impacts fertility is something none of us can control: age.

For healthy women, fertility peaks in their mid-20s, begins declining at age 27, then nosedives around age 37. If you are in your mid 30s or older and trying to conceive, you need to be very pointed in your efforts. That means figuring out when you’re ovulating and having sex at those optimal times. And if you’re over 35 and concerned about your fertility, don’t settle for a gynecologist saying “Just give it time,”. It is advised to women age 35 or older to consult a fertility specialist if they fail to get pregnant after six months of unprotected intercourse. Women ages 37 to 40 should wait no longer than three months.

Sexual positions -- coital or postcoital -- don't affect your chances of conception.

No study has confirmed that one position is more effective than any other in achieving pregnancy. In fact, sperm can be found in the cervical canal mere seconds after ejaculation, regardless of position. Of course, aiming for the deepest penetration and maximum cervical contact makes sense, but the optimal position varies because every woman’s body is different.

And since sperm start swimming immediately after ejaculation, it isn’t necessary for a woman to become a gymnast or a yoga master to make a baby. There may be a little advantage to lying around after intercourse to keep the sperm inside you, but there’s absolutely no value in standing on your head. So, savor the mood however you please.

The biological clock ticks for men too.

The notion that age-related fertility decline is only a female factor has been debunked by a recent British study. Researchers at Bristol and Brunel Universities evaluated 8,500 couples to determine the impact of age on the length of time it took to conceive. They discovered that while only 8 percent of men younger than 25 fail to impregnate their partner after a year of trying, that number grows to 15 percent after age 35. Despite other factors, such as the fact that frequency of intercourse drops off with age, the study suggests that paternal age, too, may be a consideration for couples struggling with infertility.

However brief your partner's particular choice of underwear, it's unlikely that it will impact his fertility.