1st month of pregnancy: the beginning of a wonderful adventure!

Congratulations, you’re pregnant! A lot of things will happen in this first month: you will feel some of them while your unborn child develops a little more each day. What’s in store for you? Tiredness no doubt, perhaps morning sickness, but above all a great deal of joy!

Dating the start of your pregnancy and getting used to the idea

The first month of your pregnancy starts with a fabulous encounter: your oocyte meets the strongest of your partner’s sperm. Depending on your menstrual cycle, this encounter manages to take place on around the 14th day after the start of your last period1.

This fusion results in what is known simply as an egg. But this egg is already extraordinary: it contains all the genetic characteristics of your unborn child! The colour of their eyes, their gender, their size, and so on.

And this little egg starts with a journey: it travels to your uterus to find the best place to stop and implant.


At that moment, you don’t yet know that you are pregnant, but the incredible adventure has already begun!

Week of pregnancy? Week of amenorrhoea? The language of pregnancy

From the moment you discover you are pregnant and it is confirmed, you are going to get to know the language of pregnancy!

The medical community will talk in weeks of amenorrhoea2, or WA for short.

In WA, your pregnancy is dated from the first day of your last period, so there is a difference of about two weeks2 between this day and the actual start of your pregnancy.

Keep in mind the dates in weeks of amenorrhoea, this is your new language for the next 9 months! Lastly, this date of the first day of your last period is important for another reason: your doctor will use it to calculate your due date… but a lot will happen before then!

1er mois de grossesse : à quoi ressemble votre futur bébé ?

From the moment it implants into your uterus, the egg cell will start dividing. Microscopic to start with, it will then look like a little blackberry, before starting to resemble a tiny tadpole at the end of the first month. On one side, the beginning of the brain and head, on the other, the coccyx and the buds of the arms and legs... it measures approximately 5 mm2. And you? You have started to manufacture the future placenta, which will incredibly be responsible for all the exchanges with your unborn child.

1Laurence Pernoud et Agnès Grison, J’attends un enfant, éditions Pierre Horey 1998.


2Béatrice Knoepfler, with the participation of Dr Jean-Philippe Bault, Le calendrier de votre grossesse, Eyrolles.

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Breast milk is the ideal food for infants. WHO recommends breastfeeding exclusively for the first 6 months and then continuation thereof until the age of 2 alongside the introduction, from 6 months, of safe and appropriate complementary foods. Please consult a healthcare professional if you need any advice about feeding your baby.