Week-by-week guide to pregnancy

happy couple looking at pregnancy test results
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!

1st 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.

Week 12 – your 1st trimester

Hopefully you are starting to feel much better as the 1st trimester comes to a close.

What's happening in my body?

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 calm 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.

You may wonder if your bump should look bigger or smaller. There are so many factors that determine how big your stomach gets including:

  • your hormones
  • pre-pregnancy weight
  • how many babies you've already had
  • the strength of your muscles

Gaining weight

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 to 12.5kg (22lb to 26lb), and that's usually after week 20. But some may not put on any weight at all. You can find out more about weight gain in pregnancy on the NHS website.

Try to follow a healthy pregnancy diet, you do not need to eat more for the baby. When you enter the 3rd trimester in week 28 you can add another 200 calories a day to your diet – that's about 2 slices of wholemeal toast with margarine.

If you maintain a healthy weight, your baby is more likely to be a healthy weight too. Being overweight makes you more prone to conditions such as pre-eclampsia and high blood pressure.

Foods to avoid in pregnancy

There are certain foods you should while you're pregnant. Read about foods to avoid on the NHS website.

Want to know when the baby's due?

Use the NHS 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).

Early pregnancy symptoms (at 12 weeks)

Your signs of pregnancy may include:

  • an aching stomach
  • nausea
  • mood swings
  • a metallic taste in your mouth
  • sore breasts
  • indigestion and heartburn
  • headaches
  • dizziness
  • new likes and dislikes for food and drink
  • 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 (read ways to cope with bloating on week 10's page)

Read Tommy's guide to common pregnancy symptoms.

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 3 grapes.

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 will not be able to tell your baby's sex until later.

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.

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 8 and 12 and takes around an hour. You can talk about the options for your pregnancy and the birth. You will also 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.

If it's your first pregnancy, you will probably have around 10 appointments and 2 scans in total.

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 in a safe environment.

Ask your midwife or doctor about online antenatal classes – they may be able to recommend one. The charity Tommy's has lots of useful information on antenatal classes and preparing you for birth.

Antenatal classes give you the chance to meet other people and prepare you for parenthood. The NCT offers online antenatal classes with small groups of people that live locally to you.

Do your best to stop smoking, give up alcohol and go easy on the tea, coffee and anything else with caffeine. Ask your midwife or GP for support if you need it.

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.

To keep bones and muscles healthy, we need vitamin D. From late March/early April to the end of September, most people make enough vitamin D from sunlight on their skin. However, between October and early March, you should consider taking a daily vitamin D supplement because we cannot make enough from sunlight.

Some people should take a vitamin D supplement all year round, find out if this applies to you on the NHS website. You just need 10 micrograms (it's the same for grown-ups and kids). Check if you're entitled to free vitamins.

It's recommended that you do 150 minutes of exercise a week while pregnant. You could start off with just 10 minutes of daily exercise - perhaps take a brisk walk outside. Check out Sport England's #StayInWorkOut online exercises (scroll to the pregnancy section). Listen to your body and do what feels right for you.

There's no need to eat for 2. 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 keep it to yourself. It's important that you ask for help if you need it.

Getting pregnant again might be 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. 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.

You and your family should follow the government and NHS guidance on coronavirus (COVID-19):

  • read government guidance on how to stay safe from COVID-19
  • get NHS advice about COVID-19
  • use the NHS COVID-19 app for England and Wales – it's the fastest way of knowing when you've been exposed to COVID-19
  • To find out about about COVID-19 and pregnancy, childbirth and breastfeeding, have a look at advice on the:

  • NHS website
  • Breastfeeding Network
  • World Health Organization
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