Your week by week guide on what to expect when you're expecting...

1 – 4 Weeks Pregnant

The length of your pregnancy is measured from the first day of your last menstrual period, not from the day of ovulation or conception as many people might think.  It can be really confusing to find out you are pregnant, perhaps 14 days after ovulation, and then to discover you are already 4 weeks pregnant!!

On a positive note, this means you will only have 8 months left of your pregnancy, and things are already further along than you thought!

If your cycle is longer than 28 days then you will not be as advanced as you thought as, for you, ovulation takes place later, perhaps at 21 days and similarly if your cycle is shorter than 28 days, e.g. 21 days, then your baby will be due a week earlier than if you had a 28 day cycle.

At the moment your baby is referred to as an “Embryo” and is a ball of rapidly dividing cells about the size of the head of a pin!  He or she will not yet look like a baby, but more like a tiny tadpole.

Folic Acid

As soon as you know you are pregnant, and ideally, before you start trying to conceive, you should take Folic Acid on a daily basis.  It is important to take Folic Acid (which is also known as Vitamin B9) during the early weeks of pregnancy as it can significantly reduce the risk of  what are known as neural tube defects (NTDs), such as Spina Bifida (Spina Bifida is a birth defect which affects the development of the spine and central nervous system causing a wide range of issues such as mobility problems, cognitive problems and bowel and bladder problems).

Folic Acid is readily available in the form of daily capsules. This only needs to be taken until 12 weeks, after which point the baby is fully formed and the Folic Acid is no longer needed (unless otherwise advised by your Doctor).

Vitamin D

It is now recommended that all pregnant women take 10 micrograms of Vitamin D per day throughout the pregnancy and whilst breastfeeding.  You may be able to get this for free through your local authority- please ask your GP.

Implantation Bleeding

About one third of pregnant women experience implantation bleeding, this occurs when the fertilised embryo implants itself into the wall of the uterus. This is normally about 7-10 days after ovulation and can be accompanied by period-pain style aches and pains – many women mistake these symptoms as a sign that their period is coming.  The blood is likely to be pinkish or brown and is not normally heavy like a period. Unfortunately you may not get a positive pregnancy test whilst this bleeding is occurring, as it is just too soon to show up.

If the pain becomes severe or the bleeding becomes heavy or is accompanied by a fever then you must seek medical advice as soon as you can.

Pregnancy Tests

New and more sophisticated pregnancy tests can detect pregnancies much earlier than ever before, some even before you have missed a period.  The advantage in this is obvious- in knowing you are pregnant sooner and making changes such as giving up smoking/drinking or being shot out of a cannon or beginning to take Folic Acid.

However, the disadvantage is that by discovering you are pregnant much earlier, you may be more affected by a miscarriage that perhaps, previously, would have passed without note. If you had not known you were pregnant you might have put this early and “unknown” miscarriage down to a late or heavy period.

These early tests have shown doctors that there are a larger number of early (before 14 weeks) miscarriages than was previously thought.

The NHS states that 1 in 5 confirmed pregnancies ends in a miscarriage.  For more details on this subject, please see our section on Miscarriages.


A positive pregnancy test means that the hormone HCG has been detected in your urine.  This means only one thing, which is, conception has occurred and a pregnancy has begun.  A pregnancy test is very accurate and you will not get a false positive.  It is however possible to get a false negative, perhaps if you test too early or if you do not perform the test accurately.  So if you think you may be pregnant but received a negative test, it is worth waiting a day or two and then trying the test again.  If you have received a positive result, it is not necessary to test again, although many of us cannot believe our eyes and do the tests repeatedly, which can be very expensive! 

At this stage, you should make contact with your GP and ask them to arrange a viability scan for you.  Try to continue as normal and try not to get too excited at this very early stage as there is a long way to go.

 An Early Scan?

Waiting 12 weeks until the all-important scan can feel unbearable.  However, as soon as you have made contact with your doctor or midwife, you can request a dating scan which will confirm your pregnancy and help you to plan the date of your 12 week scan and nuchal scan (should you chose to have one).  Many people do not seem to know that this early scan is available to them – and perhaps your GP or doctor may not be forthcoming in offering this to you, but it is a provision made by the NHS for pregnant women in this country.

You should bear in mind that until some time between 6 and 7 weeks, a heartbeat is unlikely to be detected in the embryo, so a scan at 4-5 weeks can only show that conception has occurred, and not that a fully formed embryo is developing.  It is ideal to wait until at least 6 weeks before you go for a scan as the results of a scan before then may be inconclusive and disappointing.

Worrying about a miscarriage

Many women worry about the possibility of a miscarriage in the first 12 weeks, particularly if they have already had a miscarriage before.  So, if you find yourself unable to relax and continually scared by this prospect – it is possible to go for a private scan to give yourself peace of mind. The cost can range from around £100 to £300 but for some people this represents great value for peace of mind, but again, if you can wait until 6 or 7 weeks this is a good idea.

Sore Boobs

Your breasts may start to grow or ache more than you thought possible.  Some women can grow a couple of cup sizes almost immediately.  If this is the case- invest in a bigger bra! Do not worry about wearing under wired bras.  We have heard people say that wearing an under wired bra will affect the health of your breasts and perhaps even affect milk production later in the pregnancy- but we cannot find any scientific evidence to suggest that this is true.  The most important thing is to have a comfortable and well-fitting bra that is not too tight and offers the right amount of support.


Nausea or “morning sickness” is not likely to occur just yet but can start early in some cases.

Your body will start to retain more water so you may experience some bloating and weight gain.
You may also find yourself weeing more frequently as body produces more urine.

You may be feeling a whole range of emotions – from irrational fear – to extreme happiness.  Many women become very emotional about not only their pregnancy but other things around them.  Do not be surprised if you find yourself blubbing at an episode of something innocuous like Masterchef!

It can be difficult not to think about your pregnancy obsessively– all day every day  – this could be an explanation for the often cited “baby brain” and is quite normal.

If you have not yet told anyone apart from your partner these early weeks can seem very long and lonely.  Sharing your news and your fears and excitement with a close friend or even a colleague at work can feel like a relief.  It feels good to have an ally in the early stages and should anything go wrong during these first few weeks you may be glad that you have someone you can talk to.

It is advisable to cut out alcohol completely during the first 12 weeks of your pregnancy and to moderate your caffeine intake.

Read about the next stage, 4 – 8 Weeks

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