Even though this week counts as week 1 of pregnancy, you are not actually pregnant yet
This week counts as part of your 40 weeks of pregnancy, but you aren't officially pregnant until week 3 as conception occurs about two weeks after your period.
Your egg has left the ovary
You are now ovulating and your egg will begin to travel through the fallopian tubes.
Your baby's sex is already decided
Your egg has now been fertilised and the first steps in your baby's development have begun. Whether you are having a boy or a girl is now decided.
Once the sperm has fertilised the egg, your baby's sex is already determined. So even from this very early stage it is already decided whether you will have a little boy or a little girl. Once fertilised, the egg and sperm (now called the zygote) divide rapidly producing more and more cells until a cluster of cells called a blastocyst is formed. This will then attach itself to the uterus wall where it will grow and develop over the next 37 weeks.
Follow the food pyramid as your guide for healthy eating. A healthy balanced diet now will not only help to keep your energy up during the tiring first trimester, but it will also help to get your baby off to the very best start. Research into early life has shown that environmental factors - such as nutrition - will play an important role in your baby's health not just now but for their whole lives.
Your baby is called an embryo at this stage
Until around week 8 of pregnancy the medical term for your baby is an embryo. After this they will be referred to as a foetus.
Your baby will double in size by the end of the week
You may not feel like you are pregnant yet but that doesn't mean that there isn't a lot happening! Even at this early stage your baby is developing rapidly and the neural tube is already forming.
Your baby's heart will soon start to beat
Already, your baby is receiving nutrition and oxygen through your placenta. This will continue to pass them nutrients from you and oxygen throughout the next 8 months.
Baby's lungs, liver and pancreas are all being formed
You may be feeling tired at the moment and it is no wonder with all that's going on inside you. Your body is getting used to lots of physical changes and your baby is growing rapidly.
Your baby's heart is beating twice as fast as yours
An adult's heart usually beats around 60 - 100 times per minute but your baby's is already beating 150 beats per minute - this will even increase further to 170 in a couple of weeks.