Weeks 1 & 2 of pregnancy: What to expect

So, what’s going on inside in this first two weeks?

Your uterus is building a new lining and your ovaries are preparing to release an egg (maybe more than one!). Ovulation typically occurs 10 – 16 days before your period comes, so around the midpoint of an average 28-day cycle.

Conception, or fertilisation, therefore usually falls in week three of your pregnancy.

Some people are very aware of their cycle, and the signs of ovulation, whereas others find it difficult to keep track of their periods. If you are trying to conceive, you might take note of symptoms that suggest you’re ovulating, including:

If you’re trying to keep track, ovulation predictor kits can provide help identifying the higher hormone levels that indicate ovulation.

Although there are no medical symptoms or signs of pregnancy immediately after fertilisation, women often have an instinct that tells them otherwise. You might notice a state of mind that you’ve never felt before, where you feel happy and satisfied as if you’d completed a major task. However, this alone is not a guaranteed sign of pregnancy.

Possible signs of pregnancy are generally divided into three categories.

If you notice these signs, there's a chance you may be pregnant:

Once you notice these signs, you can almost certainly assume that you are pregnant:

Medical certainty established by:

Individual symptoms from the first two lists of signs will not tell you for certain that you are pregnant, but they might lead you to suspect it. Only if you experience multiple symptoms at the same time will your suspicions grow, in which case a pregnancy test may be a good idea. Once you are certain you are pregnant, your due date can be calculated by using our Due Date Calculator.

In weeks 1 and 2, there is still nothing to be seen of the embryo, as your child is initially known when they begin to develop in your womb.

It’s not until week 3 that a very small embryo may be visible in an ultrasound scan.

Your baby’s development

“Embryo” means an unborn offspring, and the term is used to describe the fertilised egg from week 4 of pregnancy. From around week 10, when all vital organs have formed, we stop referring to your child as an embryo and start using the word foetus instead.

You may well be using a pet name for the unborn baby in your tummy - Peanut or something cute like that - and that's great! We prefer to avoid medical terms like "embryo" or "foetus" as far as possible, so we'll talk instead about your baby/unborn child, etc.

The egg which has matured so that it can be fertilised by the male sperm is between 0.11 mm and 0.14 mm in size at this stage, which means it can’t be detected without using technology. It contains all your genetic information and is therefore a hugely important part of the developing embryo.

Folic acid supplements

If you're hoping for a baby, or suspect you may be pregnant, it's wise to take folic acid supplements. In the first 12 weeks of pregnancy, your baby’s brain and spinal cord start to develop. Getting enough folic acid in this first trimester helps reduce the risk of problems occurring during this development, which might lead to conditions such as spina bifida. Eating foods rich in folic acid is also a good idea; here's a list of the top ways to get folic acid in your diet.

Talk to your GP about medication

If you're trying to conceive, talk to your doctor about any medications you're taking to ensure they are safe to take during pregnancy. It’s safe to take paracetamol during pregnancy, but aspirin and ibuprofen should only be taken under advice by your doctor.

It’s time to stop smoking

If you smoke, the best thing you can do for the health of your baby – and yourself – is to give up as soon as you find out you are pregnant, or even earlier if you can. If your partner smokes, ask them to do the same, as second-hand smoke can also be dangerous.

For more information and help to stop smoking during pregnancy, you can speak to your GP, visit the NHS website, or contact the NHS Smoking Helpline on 0300 123 1044 (England only; Monday to Friday 9am to 8pm, Saturday and Sunday 11am to 4pm).

Some home pregnancy tests can show positive results before your period is due, but typically the earlier you test before your missed period, the less accurate the results. For example, the ClearBlue digital tests can be used up to 5 days before your period is due, but the accuracy of the result is put at around 60% compared to 98% accurate when used the day before your period is due.

For optimum results, wait until your period is due and take the test first thing in the morning when the urine is most concentrated.

If you’ve arrived on this page because a pregnancy test has told you you’re 1 – 2 weeks pregnant, congratulations!

But you can skip ahead, because those tests date from conception, and not from the first day of your last period. So, you are slightly further along than you think. 

Use our due date calculator to work out when your baby is due.

Trying to conceive can be a stressful time, particularly if you have been trying for a while or are trying after a loss. Be kind to yourself. Practice positive self-talk and get into healthy habits in terms of diet and keeping active, so that you are in the best possible position for a healthy pregnancy.

What are the first signs of pregnancy?

As discussed, this first two weeks is not like the rest of your pregnancy – there aren’t really any signs or symptoms to be aware of, although you may notice the symptoms of ovulation.

In terms of what to look out for in the coming weeks, the obvious thing to look for is a missed period, as well as tender or sensitive breasts, fatigue and possibly nausea.

Confirm these symptoms with a pregnancy test.

Is diarrhea a sign of pregnancy in the first week?

Diarrhea is not a classic symptom of pregnancy, though for some women it does go hand in hand with abdominal cramps – as might be experienced during implantation – as well as the hormones associated with pregnancy and/or menstruation.

What should I avoid during the first 2 weeks of pregnancy?

Avoid smoking, alcohol, and too much caffeine. Talk to your doctor about any medications you’re taking that might be unsuitable to take during pregnancy.

Will a pregnancy test be positive at 1 week?

A pregnancy test could be positive one week post-conception, depending on the pregnancy test you use and where conception falls within your cycle. Some pregnancy tests can give positive results up to 5 days before a missed period. However, the first week of pregnancy technically begins on the first day of your last period, at which point the egg has not been fertilised and a test would not return a positive result.

Got questions? At the HiPPBabyClub, we bring you real-world advice and support from HiPP parents, midwives, nutritionists and more. Join our Baby Club to find out more.