Category Archives: My reproductive system

How and when does a pregnancy start?

How do I become pregnant?

To become pregnant, you need a single sperm to fuse with an egg. This process is called fertilisation

Pregnancy does not begin until the fertilised egg has implanted in the womb, after having travelled through the fallopian tube.

So if you’ve just had unprotected sex or contraceptive failure, no pregnancy will start until at least the sixth day. This means you have time to take a morning after pill, such as ellaOne, if you are not planning on becoming pregnant.

ellaOne is available from your local pharmacy, doctors, Family Planning Clinic or walk-in centre.


Signs of pregnancy

  • Late period
  • Feeling sick (nausea)
  • Being sick (vomiting)
  • Tiredness
  • Breast tenderness or soreness
  • Needing to pee (urinate) more often

If you think you might be pregnant, take a pregnancy test and/or visit your doctor. If you are pregnant it is too late for emergency contraception because it works to prevent an unintended pregnancy. It will not affect an existing pregnancy.



Can you get pregnant at any time in your cycle?

When can I get pregnant?
In theory, during the average woman’s menstrual cycle there are six days when sex can result in pregnancy. This conception risk period, also called ‘fertile window’ is the five days before egg release (ovulation), plus the day of egg release.


You are at risk of conception if you have unprotected sex in the five days before ovulation because sperm can live for about 5 days, and can be waiting in the fallopian tubes, ready to fertilise your egg. Unless fertilised, an egg only lives for 24 hours.

The highest risk of pregnancy is when ovulation happens shortly after unprotected sex

Sperm is viable for five days, however viability reduces over time. This means that the risk of conception is highest when ovulation happens during the first three days following unprotected sex.

When am I most fertile?

You have no exact way of knowing when your fertile window is and it can be at a different time every month. This means that you are at risk of pregnancy almost throughout the whole of your menstrual cycle.

  • You might not ovulate on the same day of your cycle from one month to another
  • Women with a regular cycle can be in their fertile window any time from day 6 to day 21
  • If the cycle is not regular, the fertile window may be even later in the cycle
  • It is difficult to predict when your fertile window may be, and it can be a different time every month

If you have unprotected sex at any time, or if the condom breaks or splits, make sure you take the morning after pill if you are not planning on getting pregnant.

What is ovulation?

What happens when you ovulate?


Ovulation is the release of an egg from the ovaries. A woman is born with all her eggs. Once you start your periods, one egg (occasionally two) develops and is released during each menstrual cycle.




After ovulation, the egg lives for approximately 24 hours



Once the egg is released from the ovary it travels down the fallopian tube towards the womb. Fertilisation happens if sperm meets and fuses with the egg. Sperm can survive in the fallopian tubes for up to five days after sex.




If the egg is not fertilised, hormone levels fall, and the womb lining comes away and leaves the body as a period.


A woman cannot get pregnant if ovulation does not occur.

Understanding the menstrual cycle

The menstrual cycle is the process where an egg develops each month and the lining of your womb is prepared for possible pregnancy

The menstrual cycle is driven by body chemicals called hormones. A cycle is counted from the first day of bleeding (your period) to the first day of your next period. The rise and fall of hormonal levels during this time control the menstrual cycle.

What’s happening in your womb?




What’s happening to your hormones?

The menstrual cycle is controlled by a complex interaction of hormones. In each cycle, increasing levels of hormones cause the ovary to develop an egg and release it (ovulation). The womb lining also starts to thicken.

The female reproductive system

How the reproductive system works

The reproductive system, sometimes called the sexual organs, is the set of organs needed to make a baby.

A woman’s reproductive system is made up of a vulva, vagina, cervix, womb, fallopian tubes, ovaries and breasts. Unlike men, most of a woman’s reproductive system is located inside the body.