The biggest miracle of life has begun inside your body and you are probably not even aware of it yet. The only sign is that your period is late. Meanwhile a group of cells has formed from your egg and your partner's sperm, attached itself to the wall of your uterus, and become an embryo. At this point your baby's sex is already determined.
Immediately after menstruation a new lining starts to be prepared in the uterus, ready to receive and nourish a fertilised egg, while a new egg travels from the ovaries and awaits fertilisation. During sexual intercourse 250 million sperm are released, but only one of them is destined to 'conquer' the egg.
Over the next 30 hours the genetic code of the egg (the mother's) and the sperm (the father's) combine and create the genetic code of your baby. At this moment it is already decided whether your baby will be a boy or girl. The cells of the fertilised egg immediately start to divide. At the end of the third week of pregnancy, the egg implants itself in the womb. It divides into two halves, from which the placenta and the embryo are formed. Up until the end of the fourth week the embryo is the size of a poppy seed.
Although the conception of a child is a little miracle, the future mother is usually not even aware of it. Not until the end of the fourth week, or at best a week after a missed period, will a pregnancy test confirm pregnancy with certainty. If you are trying to conceive, it is important not to put yourself under too much pressure worrying about when it's going to happen. It is better to focus on the love and closeness of your partner.
Did you suspect you were pregnant even before missing your period? Write it in your diary!
Although having twins is a lot more common today than it once was, the likelihood of conceiving identical twins, i.e. from a single egg, has remained at the same level around the world for decades. In the same period the likelihood of fraternal (non-identical) twins, i.e. twins from two eggs both of which are fertilised, has increased as a consequence of the increase in the average age of mothers at conception and as a result of hormone therapies and artificial insemination.