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 15 – your 2nd trimester

If you use public transport, you might want to order a “Baby on Board” badge to prompt other commuters into giving up their seat for you. You might feel fine now, but as you get bigger, you will be more unstable on your feet, and falling over could be stressful and even dangerous.

What's happening in my body?

Your baby is growing quickly and comes with a lot of packaging (the amniotic sac and fluid) and their own food supply (placenta). You could start getting the odd jabbing pain on the sides of your bump. This is known as "round ligament pain", putting your feet up and resting can help.

Your skin could also feel a bit itchy. It might help to use an unperfumed moisturiser, wear loose cotton clothing and have a cool bath. If the itching gets worse especially at night, talk to your doctor or midwife. Read about itching in pregnancy on the NHS website.

Changes in your pants

Have you noticed a lot of discharge in your pants? Many women get this. There's more blood flowing around your pelvic area and that can cause your body to produce more of the milky fluid called leucorrhoea that keeps your vagina clean and free from infection. See your doctor or midwife if:

  • it changes colour – it should be clear, white or creamy
  • it smells bad – it should smell slightly musky, not strongly of fish or anything else
  • it changes texture – for example, it starts going frothy or looks like cottage cheese
  • you get pain when peeing
  • you feel itchy or sore


If you have a vaginal infection, it's likely to be thrush, which is a common yeast infection.

Signs include a lumpy white discharge, itching around your vagina, and stinging when you pee or have sex.

To help prevent thrush:

  • wear loose cotton underwear
  • use unperfumed soap or body wash
  • steer clear of sex until it's cleared up

There are more tips to beat thrush on the NHS website.

2nd trimester pregnancy symptoms (at 15 weeks)

Your pregnancy symptoms may include:

You may also experience symptoms from earlier weeks, such as:

Read Tommy's guide to common pregnancy symptoms.

What does my baby look like?

Your baby, or foetus, is around 10.1cm long from head to bottom, which is about the size of an apple. The weight is around 70g, which is the same as a small bag of salad.

Your baby has been busy growing a soft layer of hair, called "lanugo", all over their body. Their eyebrows and eyelashes are also starting to develop. Your baby's eyes are now sensitive to light.

Around now, your baby will start hearing too. Talk to your baby and they will probably hear you. They will also hear your heartbeat and any noises made by your digestive system.

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, cough or jump. Get the muscles going by pretending that you're having a wee and then stop the "urine" in midflow. Visit Tommy's for more ideas about 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, they're 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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