4 weeks pregnant - signs, fetal development and what to consider

As you progress into your fourth week of pregnancy you may notice some subtle changes in how you feel. 

To put your mind at rest that everything you're experiencing is normal we've put together a guide on all the usual signs and symptoms of being 4 weeks pregnant, as part of our pregnancy, week by week guides. 

Symptoms at 4 weeks pregnant

You probably won't be feeling any different physically just yet, but studies show around 15-25% of women will experience some light spotting as the fertilised egg implants. This is known as implantation bleeding. It can last for a few days and can be mistaken for a light period. Don't worry, though, any doubts about your dates will be cleared up with your dating scan which happens between weeks 8 and 14 of pregnancy.

It's completely normal to feel a little anxious at the start of your pregnancy - your body is undergoing a huge change after all. Be sure to speak to your family and friends as much as possible and reading up on your pregnancy week by week will help you understand the changes you are experiencing.

Fetal development at 4 weeks pregnant

The fertilised egg bundle nestles into the lining of your uterus which then grows protectively over the bundle. The placental tissue begins to produce the hormone HCG which is the hormone detected during a pregnancy tests. For the impatient among you there are early pregnancy tests on the market (available on Amazon) that are able to detect this pregnancy hormone before your period. 

Your unborn baby's so tiny it could fit on the head of a pin at the moment! By the time it reaches the uterus, the rapidly dividing ball of cells - now known as a blastocyst - has separated into two sections. The inner group of cells will become the embryo. The outer group will become the cells that nourish and protect it. The placenta, which will nourish your baby throughout the pregnancy, also begins to form.

Things to consider at 4 weeks pregnant 

When trying for a baby you may not know that you are pregnant for several weeks after conception. So even before that positive test result, follow the guidelines for healthy eating in pregnancy and familiarise yourself with foods to avoid as they may pose a risk to your growing baby.

It's recommended you take a daily 400mcg folic acid tablet (available from Amazon) from now and continue taking it up to week 12 of your pregnancy. This will significantly reduce the risk of your baby having spina bifida or other neural tube defects.

Further advice and information:

• Visit the NHS for more pregnancy week by week advice 
• Download a pregnancy tracker app
• View all our pregnancy week by week guides