Understanding your monthly cycle

The first phase starts with the first day of your period. Your body releases hormones that stimulate eggs to grow within follicles inside your ovaries. Between day seven and 11, those hormones also help thicken the lining of your uterus to get ready for the implantation of a fertilised egg.

What happens during ovulation

Most women have a cycle of between 24 and 35 days long. On average, if ovulation happens it does so between 10 and 16 days before your next period, although it can be different for every woman. Rising estrogen causes a brain hormone called luteinising hormone (LH) to surge, triggering the release of the egg that's most ripe. At the same time, your cervical mucus changes to a slippery, egg-white consistency, to help sperm to make their way to the egg.

It's all in the timing

Women are born with about 1 million eggs, but only 300 to 400 will be released through ovulation. Usually just one egg is released each month. The egg (left) travels down the fallopian tube, where it is ready to be fertilised, towards the uterus. The egg only lives about 12 to 24 hours. Sperm can live for up to seven days, so knowing you’re due to ovulate soon can help you and your partner plan sex for when you're most likely to conceive.

Tracking your most fertile days

Generally, women are most fertile during the days just before and during ovulation. If you have a regular 28-day cycle, count back 14 days from when you expect your next period to start. Plan on having sex every other day around that day - say days 12, 14, and 16. Your cycle may be longer or shorter, so using an online ovulation calculator may help identify the likely day.

Tracking ovulation by temperature

After an egg is released, what's left of the follicle – the corpus luteum – releases the hormone progesterone to help thicken the lining of the uterus and maintain a pregnancy. Progesterone causes your body temperature to go up slightly. Taking your temperature every morning with a digital thermometer before getting out of bed is one way to track ovulation. It's inexpensive, but not as accurate as other methods. You'll need to chart your temperature for a few months to predict when you'll be fertile.

Tracking ovulation by hormone

Rising estrogen that causes a surge in LH is what triggers the egg to be released from your ovaries. Using ovulation kits to check these hormone levels in your urine can help you pinpoint the day of ovulation. Some kits allow you to test daily to determine when you are ovulating. These kits are more expensive than thermometers, but may be more convenient and are very accurate.

The last phase of your monthly cycle

The lining of your uterus thickens to get ready for a fertilised egg to implant. If the egg isn't fertilised, it disintegrates and about 12 to 16 days later, it - along with blood and tissues from the lining of the uterus - is expelled. That process, which usually lasts 3 to 7 days, is menstruation, also called your period. Then the cycle begins again.

Foods that may help ovulation

Choose monounsaturated fats (like olive oil) over trans fats (those in fast food, cakes and pastries); vegetable protein (beans) over red meat; and high-fibre, low-glycaemic foods – whole grains, vegetables, and some fruit – over refined carbs and sugars. This is the time to start a prenatal supplement with folic acid to prevent spinal tube defects in your baby.  The U.K. chief medical officer recommends 400 micrograms of folic acid every day while you're trying to get pregnant through the first 12 weeks of your pregnancy.

Weight affects fertility

A study of women found that those whose body mass index (BMI) was above normal took twice as long to get pregnant as those with a normal BMI. In men, those who are obese are more likely to have low testosterone. Some research has suggested a 9kg (20lb) weight gain can increase the risk of infertility by 10%.

Age affects your conception chances

A woman's decline in fertility starts around the age of 30. The NHS says a woman should talk to her GP if she's under 35 and has been trying to conceive for more than 12 months, or sooner if she's over 35 or has other concerns, such as polycystic ovarian syndrome (PCOS) or endometriosis. A progesterone blood test can help establish if a woman is ovulating.

Fertility declines in older men too

Studies show that sperm count and motility (movement) usually decrease as men age. One study found that it took men age 45 or above longer to achieve a pregnancy once the couple started trying to conceive. If your partner is older, you may want to talk to your GP about ways to boost your chances of conception.

How men can boost fertility

Managing stress, avoiding alcohol, tobacco and recreational drugs, maintaining a healthy weight, and eating a diet high in zinc (found in meat, whole grains, seafood and eggs), selenium (meat, seafood, mushroom, cereals and Brazil nuts) and vitamin E can help improve male fertility. Keep the testicles cool -- no long hot baths, hot tubs or saunas -- which can decrease the number of sperm.

Treatments for infertility

A number of factors can cause infertility, so the first step is for your doctor to evaluate you and your partner. Infertility treatments can include taking fertility drugs to stimulate ovulation and in-vitro fertilisation (IVF), which involves removing eggs from the ovaries, fertilising them, and then implanting them into the uterus.

How home pregnancy tests work

Home pregnancy tests check your urine for the "pregnancy hormone" called hCG, which your body produces once a fertilised egg implants in your uterus. Usually a home pregnancy test can tell if you're pregnant as early as six days before your first missed period. You can get a false negative if you test too early, so repeat the test a few days or a week later.

Pregnancy: Five early signs

• You miss a period.
• You need to urinate frequently.
• You tire easily.
• You’re nauseous in the morning – or all day.
• Your breasts become tender and enlarged.

Related Reading