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Info Centre - Your pregnancy: 0-4 weeks
Your pregnancy: 0-4 weeks
The stage of pregnancy from 0-12 weeks is known as the first trimester.
Pregnancy is generally measured as lasting 40 weeks from the first day of your last period, because knowing this date makes it easier to calculate your due date.
If you have a regular, 28-day cycle, conception will usually happen about two weeks after the first day of your last period. You will release an egg (“ovulate”) about 14 days before your next period is due, and the egg and sperm will meet in the Fallopian tube.
The fertilised egg will then, over a period of about 7 to 10 days, travel down the Fallopian tube to your uterus. It starts as a single cell, but as it travels, it divides again and again. By the time it reaches the uterus and implants in the lining, it consists of a 100 cells. You may lose a small spot of blood as it implants. This is known as “implantation bleeding”.
Once the fertilised egg – now known as a “blastocyst” – has been implanted, chemical signals are sent out to stop you ovulating. You will miss your next period.
At this stage, the blastocyst measures about 0.1 to 0.2mm.
By the end of week four (approximately two weeks after conception), the pregnancy is being sustained by a yolk sac until the placenta has been fully formed.
You can do a pregnancy test as soon as your period becomes overdue. These are available from supermarkets and pharmacists, and work by checking your urine for a hormone called human chorionic gonadotrophin (hcg), which is only produced in pregnancy. Pregnancy tests are generally highly reliable. You may get a false negative result if your body hasn’t yet produced enough hcg, but false positives are extremely rare. If you get a positive result, you can be sure you are pregnant.
Calculating your due date
If you want to work out your due date, take the first day of your last period and add nine calendar months and one week. So if your last period started on June 3rd, your baby will be due on March 10th. Ovulation normally occurs 14 days before your next period is due so if the gap between your periods is normally longer than 28 days, you need to take that into account. If, for example, the gap is 33 days, then add five days to your estimated date of delivery (EDD). In this case, your baby would be due on March 15th. Bear in mind that this is still a rough estimate – pregnancies can last between 37 and 42 weeks, and only five percent of babies arrive on their due date.
Taking care of yourself
There is good evidence that taking folic acid reduces your risk of having a baby with spina bifida. It is more effective if you start taking it before you become pregnant; starting as soon as you know you are pregnant and continuing till you are 12 weeks pregnant will also help.
See “Screening and testing” for more information about this.
The food you eat and what you drink or inhale can affect your baby. Your baby is reliant on you to eat the sort of food that will enable them to grow a healthy body and brain. Eating a diet that includes lots of fruit and vegetables, and foods that contain protein as well as carbohydrates and some fats, especially those that come from vegetable oil or fish, are needed for a growing baby. Some foods carry risks of infection such as listeria, toxoplasmosis or salmonella. The foods that might pose a risk include soft cheeses, such as Brie and Camembert, unpasteurised milk, raw cured meat (such as salami), raw or undercooked shellfish, raw or undercooked eggs and packaged salads.
See “Keeping healthy during pregnancy” for more information.
Also, see the NCT’s Book: Food Facts for Pregnancy and Breastfeeding.
How you may feel
You may begin to notice changes in your body that show you are pregnant, including:
- Sore breasts
- Tiredness
- Going off certain foods or developing cravings for other. Often coffee becomes disliked
- A metallic feeling in your mouth
- A need to urinate more often
- Nausea
- Sickness
Sickness experienced in pregnancy is often referred to as “morning sickness”, though many women experience it throughout the day. It is thought to be caused by the amount of hcg hormone in your body.
Sickness can be debilitating. Every woman has a different way of dealing with it, but there is no one solution that works for everyone.
Here are some tips:
- Eat little and often
- Try sucking lemons or peppermints
- Try eating ginger biscuits or drinking ginger tea
- Take vitamin B6 tablets or eat food that contains B6, such as cereals, bananas, baked potatoes, lentils or tinned fish
- Rest as much as you can.
See "Pregnancy niggles and discomforts" for more information.
Discovering you’re pregnant can unleash a host of different feelings. You may be excited and thrilled, but will probably also be anxious and apprehensive – about miscarrying, whether the baby will be all right, about giving birth, or about whether you’ll be a good enough parent. Pregnancy can also make you feel vulnerable and scared about the way you live, whether what you’re doing, eating, or taking, or how you’re feeling might be affecting your baby.
Even if your pregnancy is much wanted, you may still have a feeling of ‘Oh no, what have I done?’. By becoming pregnancy, you’ve shifted the focus of your life from yourself and you’ve set out on the journey to becoming someone’s mother. This is exciting, but it can be alarming too, as you begin to realize what a big responsibility you’re taking on.
With so many mixed emotions and concerns going through your head, it’s not surprising that many pregnant women find that their moods are up and down. Mood swings are quite normal, but if you feel persistently down or anxious, you may be suffering from antenatal depression (it’s estimated that ten per cent of women experience this - see "Antenatal depression" for more information). Talk through your concerns with your midwife or doctor if you think this might be the case. They will be able to help.
