13:43 (GMT+2), Wed, 20 July 2011
Text: Xanet van Vuuren
Illustration: Donnie Steyn
Tracking your ovulation can help to give you a good idea of when you can or can't fall pregnant during your monthly cycle.
Not all women know how to calculate their day of ovulation. It is quite a complex matter to work out, but it is very important for a woman to know when she is ovulating if she is trying to fall pregnant.
Gynaecologist and obstetrician, Dr Paul Blaauwhof from the Netcare Rosebank Hospital in Johannesburg, explains exactly what ovulation is, how it works and why it is so important for a woman to ovulate.
WHAT IS OVULATION?
Ovulation is a part of a woman's reproductive cycle in which an egg is released by a mature ovarian follicle in order to travel down the fallopian tubes towards the uterus, so it can be fertilised.
Once the egg is released, it only lives for 12 to 24 hours in which it has to be fertilised before it disintegrates. If the egg is fertilised in that time and successfully implants, you fall pregnant. But, if the egg is not fertilised and no conception occurs, the uterine lining and blood will be shed, which is the time a woman menstruates.
WHEN DOES OVULATION OCCUR?
Blaauwhof says ovulation normally takes place after a woman reaches puberty. "Ovulation usually occurs halfway between each menstrual period. So you will ovulate approximately 14 days before the onset of your next menstrual cycle."
THE OVULATION PROCESS EXPLAINED
The first part of the menstrual cycle is called the follicular phase. The first phase starts on the first day of your last menstrual period (LMP) and continues until ovulation. A normal menstrual cycle can last anywhere from 21 days until 49 days.
The second half of the menstrual cycle is called the luteal phase. This phase starts from the day of ovulation until your next period begins. This phase is more constant and is usually only 14 days from the day you will start to ovulate until the first day of your next period. You can start to ovulate from as early as day seven and as late as day 35. Sexual intercourse during this period of time can increase a woman's chance of becoming pregnant.
KEY FACTS ABOUT OVULATION
• Anything that influences the brain can influence the hormones involved in ovulation. This is why ovulation can be affected if women are stressed or ill. If a woman is stressed, she may not ovulate and this can lead to irregular menstruation or her cycle being skipped for a couple of weeks.
• When an egg is in the fallopian tube, it takes three days for it to get to the uterus, which means it takes five to seven days for an egg to get implanted from the date of fertilisation.
• A woman can still menstruate even if she hasn't yet ovulated. "There is, however, a higher change that her period will be irregular," says Blaauwhof. "She may also experience excessive bleeding or sometimes when oestrogen levels are low, she may experience spotty bleeding." Blaauwhof explains that this is not a normal menstrual cycle.
• Some women may experience a slight degree of pain or aching near their ovaries during ovulation. "This is one of the signs we make women aware of if they are trying to fall pregnant," says Blaauwhof. There is also increased vaginal discharge when a woman ovulates and her basal body temperature (the lowest temperature attained by the body during rest) in the morning will rise after ovulation.
• Normally only one egg is released each time a woman ovulates.
CALCULATING YOUR MENSTRUAL CYCLE
Blaauwhof says it is very difficult to calculate exactly when you are going to ovulate, which is why women sometimes have difficulty conceiving. "You can't actually measure your time of ovulation in a natural way – you have to rely on the normal signs of ovulation. It is often a mystery as to when you are going to ovulate if you try to measure it naturally without using tests. You can, however, measure your menstrual cycle and take your temperature if you want to find out if you are ovulating or when you are going to ovulate. A woman usually ovulates on day 14, but it varies. A woman can also start to ovulate on day seven if she has a short menstrual cycle or on day 24 if she has a 38-day cycle.
It is a good idea to keep a calendar of your menstrual cycle. This will help you predict the date of your ovulation over the course of the months. The longer you keep track of your menstrual calendar, the more accurate your ovulation date will become.
Ovulation tests can be bought at the pharmacy. These tests can help you to fine-tune your time of ovulation.
It is important to have intercourse when you know you have ovulated. After that, there is not much else you can do to increase your chances of falling pregnant. Just make sure you are with your partner at the right time. "You don't need to lie with your buttocks in the air or do any other strange things to encourage fertilisation after having intercourse," says Blaauwhof.
OVULATING MORE THAN ONCE A MONTH
Blaauwhof says it is extremely rare for a woman to ovulate more than once a month, but it can and has happened. "Twin pregnancies shouldn't be confused with this. When you fall pregnant with non-identical twins, it is because you simply released two eggs at once while you were ovulating."
Thanks to Dr Paul Blaauwhof, obstetrician and gynaecologist, for his help with this article.