Your First Trimester

Whether you’re jumping for joy at the news, or feeling a bit nervous about of creating a tiny human, it’s important to know what to expect. Of course, all pregnancies are unique, so your own journey and plan will be individual to you. So discuss it with partners, family, doctors and midwives to try to make your pregnancy a positive experience for you and your future little one.

We’ve put together some of the changes that your body and mind may go through during your first trimester, pregnancy symptoms and some tips on things to do (and not do) at this first, exciting stage of your pregnancy journey.

Check out our other posts in this series: second trimester, third trimester and delivery day.

Couple with pregnancy test finding out they're pregnant


Physical changes

  • Bump may start to show at 11 weeks.
  • Hair may grow quickly and shine but it can also start falling out.
  • Skin may seem to glow.
  • Morning sickness can start at around week 6 and you may have food aversions or cravings, or a metallic taste in your mouth.
  • Breasts will grow and become tender.
  • Nails can break and split easily – try to keep them short.
  • You may experience heartburn, constipation, headaches, insomnia or bleeding gums because of inflammation.
  • You may feel more tired and even exhausted but this normally passes after the first trimester.
  • Light bleeding or ‘spotting’ can happen around the time your period would be due – this is normal.
  • You will probably gain a little bit of weight – about 3 or 4 pounds.

Lots of changes are going on in your body that may seem strange to you, and it may be difficult to understand what's totally normal and what you might need to be concerned about. Unfortunately, risk of miscarriage is the highest during the first trimester of pregnancy, so contact your healthcare professional if you have:

  • Heavy vaginal bleeding
  • Painful urination
  • Severe hands or face puffiness
  • Vision problems
  • A fever or chills

Did you know: 90% of women experience a change in skin tone during pregnancy, so don’t be worried - it’s completely normal! It’s thought it's because of the stimulation of hormones that produce more melanin pigments when skin is in the sun.

What’s going on inside?

  • Week 1-3 – ovulation and the sperm fertilises the egg.
  • Week 4 – your baby's the size of a poppy seed! Brain, spine and heart begin to form.
  • Week 5 – eyes and nose start to form.
  • Week 6 – they’re the size of a blueberry. Arms, legs, hands and feet start to form.
  • Week 7 – they’re the size of a grape.
  • Week 8 – they have paper thin skin and your womb is double its normal size.
  • Week 9 – they’re the size of a strawberry.
  • Week 10 – fingers and toes start to form. You may even be able to hear their heartbeat.
  • Week 11 – hair follicles and nail beds start to form.
  • Week 12 – they’re the size of a plum. Their wrists and elbows bend as they move.

Pregnant couple hugging

Emotional changes

  • Almost half of all pregnancies are unplanned, so whether you’re over the moon or worried about what’s to come, it’s completely normal to experience a range of emotions.
  • Dad’s mood can be affected too.
  • Hormone levels change - oestrogen and progesterone increase to prepare your body for pregnancy, but they can also leave you feeling tearful or easily irritated.
  • Relationships may blossom, but they can also become a struggle. Try talking things through, setting time aside for quality time, and dads: be aware of these emotional changes that your partner may be going through and don’t take them personally!
  • Your mood may be up and down. If you have a history of depression or your mood is interfering with your daily life, see your doctor about being scanned for prenatal depression.

Did you know: some partners, close friends or family members may suffer from couvade syndrome (sympathetic pregnancy) where they show pregnancy symptoms like having a different appetite, nausea, insomnia and weight gain. More research needs to be done in this area as there is currently no clear explanation for it and partners who experience it are often ignored.

Difficult issues

It’s completely understandable that both parents will worry when they find out they’re pregnant. Everybody knows that not all pregnancies are smooth sailing and things may not always go to plan. Sometimes this can be very traumatic, and it’s not something that you can prepare for completely, but it’s something you can learn about in case something happens to you, your partner, a friend or family member.

Depression and anxiety

1 in 5 women and 1 in 10 men experience depression and anxiety during or after pregnancy. This may be because of worries about having a baby, relationship changes, lack of support, work stress, money worries, a family history of depression, etc. Worries are often normal and generally pass, but it’s important to look out for signs of depression and to contact your healthcare professional if you have any concerns over:

  • Not wanting to socialise
  • Persistent sadness
  • Changes in appetite (that aren’t pregnancy related)
  • Feeling extremely worried
  • Lack of energy
  • Lack of interest in sex or things you normally enjoy
  • Difficulty concentrating
  • Sleep problems
  • Feeling guilty, worthless or overly agitated
  • Suicidal thoughts

These things can affect both parents, and it’s important to speak to your doctor if either of you notice them. They can help put together a plan involving therapy and/or medication to help you during this challenging time.


It’s a difficult topic to think about, but around 3 in every 4 miscarriages happen in the first trimester. One thing that influences risks is the mother’s age. For women under 30, 10% of pregnancies end in miscarriage. For women in their late 30s, 20% of pregnancies end in miscarriage. And for women over 45, 50% of pregnancies end in miscarriage.

Miscarriages in the first trimester are normally caused by problems with the foetus’ chromosomes or problems with the placenta, but they're more common when women are obese, they smoke or use drugs, have lots of caffeine or drink lots of alcohol.

Look out for the signs and contact your healthcare professional if you notice:

  • Heavy vaginal bleeding
  • Intense cramps
  • Fluid or tissue passing from the vagina

Often there’s nothing that can be done once a miscarriage starts, but it’s possible that the tissue can be tested to understand why the miscarriage happened and to possibly prevent another one. After a miscarriage, bleeding decreases over a few days.

Other complications

  • Heavy bleeding may also be a sign of an ectopic pregnancy.
  • Excessive vomiting can lead to dehydration and hospitalisation.
  • Vaginal discharge and itching may be a sign of an STI which can harm the baby.
  • A high fever may be a sign of an infection which could affect the baby.
  • Pain or burning while urinating may be a sign of a urinary tract infection which can lead to illness and affect the baby.
  • Flare ups of known medical conditions, e.g. if you have diabetes and blood sugar isn’t kept under control, it can increase your risk of miscarriage.

Take cues from your own body, and if you see any of these signs or if something just doesn’t seem right then talk to your doctor - even if it’s just for peace of mind.


What to eat

You've probably heard about needing to cut things out from your diet, but don't worry, there are so many yummy things you can still enjoy!

  • You should get most of your vitamins from food but may need to start taking extra supplements (vitamin D and folic acid).
  • For morning sickness, try ginger or chamomile tea, sparkling water, sucking ice cubes and small but frequent meals.
  • Focus your diet around high density nutritious foods (avocados, yoghurt, bananas, legumes, sweet potatoes, salmon, eggs, dark leafy greens whole grain bread, etc.).
  • You don’t need any extra calories in the first trimester.
  • It’s fine to follow a vegetarian or vegan diet – just ensure you’re getting enough vitamins.
  • Cut down on caffeine – it’s not just in coffee; it can be found in chocolate, tea and energy drinks.

Did you know: around 85% of pregnant women experience food cravings, this may be due to certain deficiencies but some research suggests that this may be psychological, with pregnancy stereotypes and changes in routine leading to indulgence.

Things to avoid

  • Alcohol and cigarettes (including second hand smoke)
  • Risky exercise such as horseback riding, skiing, football, etc.
  • Household chemicals with strong fumes or warning labels
  • Unpasteurised dairy and juices, and blue or mould-ripened cheese
  • Raw or seared food (such as sushi)
  • Rare meat
  • Foods with lots of preservatives or chemicals (such as hot dogs)
  • Raw eggs (found in cookie dough or mayonnaise)
  • High mercury fish (such as swordfish or king mackerel)
  • Raw bean sprouts

Lady rolling up her yoga mat. Yoga is a great pregnancy exercise

Well-being tips

  • If you get headaches, rest when you can, try yoga or breathing exercises, and talk to your midwife or GP about which painkillers are safe for you to take.
  • If you didn’t previously exercise, you should start being more active as there are links between pregnancy risks and being sedentary. It doesn't have to be anything scary - you could try walking, yoga, gardening, swimming, or other low impact exercises
  • Start doing pelvic floor exercises. You can do these anywhere and they will strengthen your pelvic floor muscles (that loosen due to hormonal changes) to help control accidents.
  • You can still have sex (unless your midwife has told you not to for any reason) – it won't hurt the baby and it can be great for the emotional well-being of both parents. If you’re still worried, try going on top where you can control the depth and movement, and talk to each other about how you’re feeling.
  • Try a pregnancy massage to help with headaches or backaches.
  • Remember to make time for fun! It doesn’t all have to be about being pregnant and you should continue doing things you enjoy like seeing friends, reading, going for lunch, etc.

To do

  • Get in touch with your GP who can refer you to a midwife and help to make sure you receive the right maternity healthcare.
  • Go to your first antenatal appointment with your midwife – this is called a ‘booking visit’.
  • Let them know if you've had any previous pregnancy complications, about yours and your family’s health and medical history and about your lifestyle so that they can put the best antenatal plan together for you.
  • Screening for sickle cell and thalassaemia are done before 10 weeks, so try to book in with your GP before then.
  • You may have an ultrasound scan before 12 weeks to confirm your due date.
  • Find out what you’re entitled to – pregnant women can get free prescriptions and NHS dental care.
  • Ask questions and get all the information you need from your midwife.
  • Get an STI test if you think you or your partner might have an STI, as they can affect your baby’s health.
  • Start budgeting. It’s been found that a baby costs, on average, over £11,000 in their first year. Money worries can add to stress when the baby comes, so it might help if you start planning and budgeting as soon as you know you’re pregnant

Did you know: around 2% of natural conceptions are twins, and you can find out if you’re in this percentage at your first scan!

The first trimester is so exciting, but it can definitely be a bit of a scary time. There's so much going on inside your body and this period will be different for every mum-to-be.

We hope we’ve helped you to understand the general things that can happen at this time in your pregnancy journey. Let us know if you have any questions or tips on getting through the first 12 weeks.

First trimester infographic showing stats and tips for this part of pregnancy