happy couple looking at pregnancy test results

Week-by-week guide to pregnancy

When you’re pregnant, you have lots of questions. Our week-by-week pregnancy guide is packed with lots of useful information. From what’s happening inside your body, to how your baby is developing, and tips and advice on having a healthy pregnancy – this is your one-stop pregnancy guide!

First trimester

Our week-by-week pregnancy guide is full of essential information. From early pregnancy symptoms to how your baby is growing and developing, you’ll find it all here. Happy reading!

Week 12 – your first trimester

It's been quite a journey already, hasn't it? Just 12 weeks ago, you had your last period, and now you've got a fully formed baby in your pregnant belly. You are probably seeing a midwife or doctor, and may even have had your first scan and are starting to show. Exciting times ahead!

What's happening in my body?

You are hopefully starting to feel much better as the first trimester comes to a close. There's a good chance that the placenta is now feeding your baby, having taken over from the yolk sac, and once this happens your hormones will simmer down a bit.

Your waist is probably thickening, as your breasts grow bigger. As the sickness subsides you may start to feel hungrier and worry if you're eating enough for you and the baby (see 'Weigh to go'). You may wonder if your bump should look bigger or smaller. Try not to compare yourself with other women – there are so many factors that will determine how big your stomach gets including your hormones, pre-pregnancy weight, how many babies you've already had, and the strength of your muscles. You're likely to look smaller if it's your first pregnancy and have an athletic figure, and bigger if you're pregnant with twins and you're a larger lady, but everyone's different!

Weigh to go

Many women worry about how much weight they should put on during a healthy pregnancy. The answer is 'not as much as you might think'. Most mums-to-be will put on between 10kg and 12.5kg (22lb-26lb), and that's usually after week 20, but some won't put on any weight at all. You can find out more about healthy pregnancy weight gain here.

Right now you should aim to follow a healthy pregnancy diet and don't eat more 'for the baby'. When you enter the third trimester (from week 28) you can add another 200 calories a day to your diet. Even then, that's not much – just two slices of wholemeal toast with margarine.

If you stay a healthy weight, then your baby is more likely to be a healthy weight too, and will stay that way as he or she grows up. It's also better for you not to pile on the pounds, as being overweight makes you more prone to getting dangerous conditions including high blood pressure and pre-eclampsia.

So eat for you – not two.

Foods to avoid in pregnancy

These include soft cheeses (such as brie, camembert and Danish blue) and undercooked meat. Read about other foods to avoid when pregnant.

  • It's fine to eat raw or undercooked eggs if they're stamped with a red lion logo, as the risk of salmonella is very low.

Early pregnancy symptoms (at 12 weeks)

You may be thinking 'Symptoms? What symptoms?' However some women will be suffering. Your signs of pregnancy could include:

  • an aching stomach
  • nausea – find out about morning sickness remedies
  • mood swings
  • a metallic taste in your mouth
  • sore breasts
  • indigestion and heartburn
  • headaches
  • dizziness
  • new likes and dislikes for food and drink – anyone fancy fish fingers with jam? Read our advice on weird pregnancy cravings here
  • a heightened sense of smell
  • a white milky pregnancy discharge from your vagina
  • light spotting (see your doctor if you get bleeding in pregnancy)
  • cramping, a bit like period pains
  • darkened skin on your face or brown patches - this is known as chloasma or the 'mask of pregnancy'
  • greasier, spotty skin
  • thicker and shinier hair
  • bloating and the feeling of being bloated

There's more too! Tommy's, the baby charity, has a list of 10 common pregnancy complaints with advice on how to manage them.

What does my baby look like?

Your baby, or foetus, is now 5.4cm long from head to bottom, which is about the size of a plum. The weight is about 18g, which is around the same as three grapes.

There's no doubt that this is a mini human being in the making. Everything's in the right place, from the little head to the tiny toes. The internal organs and muscles have been created. The heartbeat can be picked up on an ultrasound scan. The skeleton is made up from tissue and hardening into bone. The sex organs are formed, although most scans won't be able to tell whether you're carrying a boy or girl until later.

The baby now has an important job to do – and that's grow.

Action stations

As you start to feel more energetic, you could go and visit local maternity units and try and think about where you would like to have your baby. You can always change your mind later. You may already have ideas about how you want to give birth – this is known as your birth plan. Try and stay flexible at this stage and we'll come back to birth plans in future weeks.

This week you could…

Share the news with your GP or ask for an appointment with a midwife at your doctors' surgery. Alternatively you can refer yourself to your local hospital – look for contact details on their website.

You'll need to arrange a 'booking appointment'. This usually takes place between weeks eight and 12 and takes around an hour. You can talk about the options for your pregnancy and the birth. Plus you'll be offered screening tests for infectious diseases, and conditions such as Down's syndrome. You could ask about the Maternity Transformation Programme and how it could benefit you.

You will be offered your first dating scan any time now. This is a highlight for many women.

In total, most first time mums will have around 10 appointments and two scans. Ask if it's possible to see the same carer for your entire pregnancy, to give you continuity.

Many women will tell their employer after 12 weeks, once the risk of miscarriage reduces, and they’ve had their first scan. Once you tell your employer, you have maternity rights and can attend antenatal appointments during paid work time. You can also ask for a risk assessment of your work place to ensure that you’re working away in a safe environment.

Ask your midwife or doctor about antenatal classes in your area, as they get booked up very quickly. You could also contact your local branch of the National Childbirth Trust as they may offer classes such as yoga for pregnancy and birth workshops.

It’s early days, but ask your partner if they would like to go with you when the time comes (usually after week 28). This is the start of a new phase of your lives. These classes will give you the chance to meet other people – and prepare you for parenthood.

Do your best to stop smoking, give up alcohol and go easy on the cappuccinos. We know that’s easy to say, but hard to do. Ask your midwife or GP for support.

Do you think you or your partner could have a sexually transmitted infection (STI)? If so, get checked out, as this could affect your baby's development. Talk to your midwife or GP, or visit a sexual health clinic.

Take prenatal vitamins. You're advised to take 400 micrograms of folic acid, every day, until at least week 12. This helps your baby's nervous system to form and offers some protection from conditions such as spina bifida.

During the winter months, you should also consider taking a daily dose of 10 micrograms of Vitamin D, as it's hard to get this sunshine vitamin when the skies are grey. It's worth checking if you're entitled to free vitamins.

Get moving! It's recommended that pregnant women do 150 minutes of exercise throughout the week. You could start off with just 10 minutes of daily exercise. Perhaps take a brisk walk in the park, or go for a swim. If you start any classes, make sure the instructor knows that you're pregnant. Listen to your body and do what feels right for you.

Don't eat for two! Eat healthily, with plenty of fresh fruit and veg, and avoid processed, fatty and salty foods. You may be able to get free milk, fruit and veg through the Healthy Start scheme.

If you have a long term health condition, let your specialist or GP know that you're pregnant as soon as possible. Don't stop taking any regular medication without discussing it first with your doctor.

How are you today? If you're feeling anxious or low, then talk to your midwife or doctor who can point you in the right direction to get all the support that you need. You could also discuss your worries with your partner, friends and family. You may be worried about your relationship, or money, or having somewhere permanent to live. Don't bottle it up – you're important, so ask for help if you need it!

Getting pregnant again is probably the last thing on your mind! However now is a good time to start planning what type of contraception you would like to use after your baby is born. Making this decision when you're pregnant will give you one less thing to think about when you're looking after a newborn baby. Getting pregnant again could happen sooner than you realise and too short a gap between babies is known to cause problems. Talk to your midwife or doctor to help you decide and get everything in place.

This week's treat

Throw away your old joggers and look for maternity nightwear that will make you feel good, rather than lumpy and bumpy. It doesn't have to be pricey as you can buy maternity wear at budget supermarkets. A dressing gown or nightie will come in really handy if you give birth at a hospital or birthing unit. Get your money's worth, and wear it now too!

Want to know when the baby's due?

Use the NHS's pregnancy due date calculator.

You'll get a more accurate date from your doctor or midwife when you have a dating scan (usually at eight to 14 weeks).

Go back to week 11

Go to week 13

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