Week-by-week guide to pregnancy

group of pregnant women
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!

2nd trimester

Our week-by-week pregnancy guide is full of essential information. From staying fit in pregnancy to advice on your maternity rights, you'll find it all here.

Week 13 – your 2nd trimester

You are now a 3rd of the way through your pregnancy and you're hopefully through the worst of your symptoms.

What's happening in my body?

A small baby bump may now be visible as your uterus (womb) grows upwards and outwards. If you've been feeling the urge to pee more often, that should stop as the womb moves away from your bladder.

Meanwhile, there's a lot more blood pumping around your pelvic area and some women find that it increases their sex drive. It could also make you feel more thirsty, so drink lots of fluids.

Sex during pregnancy is perfectly safe, unless your midwife or doctor has advised you otherwise.

Infection alert

There are ways you can protect yourself and the baby from many harmful viruses and bacteria:

  1. Try to avoid contact with anyone who has chickenpox or rubella – talk to your doctor or midwife straight away if you think you could be infected.
  2. If you have a cat, get someone else to empty the cat litter tray, as the faeces could contain a bug called toxoplasma gondii. This can cause an infection called toxoplasmosis that could damage your unborn baby.
  3. You can also get toxoplasmosis from certain foods. Foods to avoid during pregnancy include undercooked meats, cured meats like salami, and unpasteurised goats' milk and cheese.
  4. Seek advice before travelling to any area affected by the Zika virus, as the virus can cause birth defects.

Read more about infections in pregnancy on the NHS website.

Coronavirus (COVID-19)

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

Teeth troubles

Swollen, painful and bleeding gums are common during pregnancy. Read about keeping teeth and gums healthy in pregnancy on the NHS website.

You are entitled to free NHS dental care during pregnancy and for a year after your baby is born. Ask your doctor or midwife for a maternity exemption certificate.

You already know the basics – clean your teeth twice a day, avoid sugary snacks and drinks, and don't smoke as it can make gum disease worse. But did you also know that:

  • a soft toothbrush is best for sensitive gums
  • you should brush in gentle circles, up and down
  • if you're sick, protect your teeth by rinsing your mouth out with water, to flush away harmful acid in your vomit
  • you should stick to alcohol-free mouthwashes to reduce plaque

2nd trimester pregnancy symptoms (at 13 weeks)

Your signs of pregnancy could include:

You may also still experience symptoms from earlier weeks, including:

  • morning sickness
  • unusual pregnancy cravings
  • heightened sense of smell
  • mood swings
  • white milky pregnancy discharge from your vagina
  • light spotting (seek medical advice for any bleeding)

Read Tommy's guide to common pregnancy symptoms.

What does my baby look like?

Your baby, or foetus, is around 7.4cm long, which is about the size of a peach. The weight is about 25g, which is as heavy as a toothbrush with toothpaste on it.

Your baby's ovaries or testes are fully developed inside and final tweaks are being made on the outside. The baby is moving around. At first the movements are very jerky and random but then they start to look more deliberate.

You may not feel any movement until around week 17. Some babies suck their thumb in the womb. This actually serves a purpose as it helps to develop their sucking reflex. They'll need this when it comes to feeding.

Action stations

Many women will tell their employer after they've had their first pregnancy scan at around 12 weeks. 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 workplace to ensure that you're working in a safe environment.

It's a good time to tone up your pelvic floor muscles. Gentle exercises can help to prevent leakage when you laugh, sneeze or cough. Get the muscles going by pretending that you're having a pee and then stopping midflow. Visit Tommy's for more information on pelvic floor exercises.

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.

Even if you've had children before, antenatal classes are still worth going to as you can meet other parents-to-be. 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.

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. You don't need any extra calories until the 3rd trimester, which starts in week 28. Try to 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.

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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