A Super Simple Guide to Your First Trimester of Pregnancy

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Published On
17 Jul, 2023
Read Time
6 minutes

Early pregnancy is an exciting time for any parent-to-be, and it's also a crucial time for the development of the foetus. It's during the first trimester that pregnant people often encounter some of the most challenging pregnancy symptoms.

We've written this guide to talk you through the first trimester of pregnancy. In it, we'll discover what symptoms are common, cover some top tips, and answer some of the most-asked questions about early pregnancy.

How long is the first trimester of pregnancy?

The first trimester starts on the first day of the last period and goes up to the last day of the 12th week of pregnancy. This period of pregnancy sees foetal development start with the egg being fertilised and ends when the foetus has all its organs, and its body systems are developing.

There are three trimesters that make up a pregnancy. After the first trimester, you move into the second trimester, then the third trimester.

First trimester symptoms and changes to your body

During the first trimester of pregnancy, many changes occur. And although every pregnancy is different, many people experience the same symptoms that're often caused by changing hormones. Common first-trimester pregnancy symptoms include:

  • Missing a period: If your menstrual cycle is regular, missing a period is often the earliest sign of pregnancy.
  • Spotting or implantation bleeding: During the initial stages of pregnancy, you might experience some light bleeding that resembles a light period. This is known as implantation bleeding and should only involve spotting or a small amount of blood loss.
  • Changes to discharge: During pregnancy, increased blood flow to the pelvic area stimulates the body's mucous membranes and can lead to an increase in cervical mucus and vaginal discharge. This symptom is commonly known as leukorrhea and is characterised by a thin, milky, white discharge.
  • Morning sickness or nausea: Morning sickness is a common pregnancy symptom that's characterised by nausea and vomiting. It typically happens during the first trimester (day or night) and is caused by hormonal changes.
  • Tiredness and fatigue: The first trimester of pregnancy involves a lot of metabolic work and so it's common to feel tired and you'll need to get plenty of rest. Remember to listen to your body and take a break whenever you need to.
  • Food cravings or aversions: You may notice that you crave certain foods or feel put off by foods and drinks that you used to like.
  • Larger, tender boobs: Increasing levels of progesterone during the first trimester can make your boobs grow and become tender, achy, and sensitive. Remember to wear a comfortable, well-fitting bra to support them.
  • Needing to pee more than usual: During the first trimester, you may feel like you need to pee more often than usual, especially at nighttime.
  • Constipation and bloating: During the early stages of your pregnancy, you may experience constipation and bloating due to the hormonal changes happening in your body. Making sure that you drink plenty of water, and eating foods that are high in fibre can help.

First-trimester pregnancy belly week by week

Although you'll experience lots of physical symptoms and changes in the first trimester, you might not notice a baby bump developing until around week 10.

It's important to remember that each pregnancy is unique. While some people may see a visible pregnancy bump by the end of their first trimester, others may not. It just depends on your body and your baby's development.

Baby's growth and development in the first trimester

During the first trimester, a baby grows very quickly and how much they develop in just a few short months is incredible.

In just a few weeks, the embryo transforms into a foetus, and major organs and body systems begin to form. By the end of the first trimester, the foetus is about the size of a peach, and all major organs and body systems are in place, although they'll continue to mature throughout the rest of the pregnancy.

Signs your pregnancy is going well in the first trimester

Although some of the symptoms you experience during the first trimester can be unpleasant, a lot of the common symptoms of early pregnancy that we've mentioned above are totally normal. They're actually signs that your first trimester is going well.

On the other hand, you may feel great and not experience these common first-trimester symptoms.

If your medical appointments confirm that everything is normal with the pregnancy, then there's no need to worry.

Danger signs of pregnancy in your first trimester

Some symptoms can sometimes be warning signs during pregnancy, and you should seek medical advice if you experience any of the following:

  • Severe abdominal pain: Stomach pain during pregnancy is normally caused by trapped wind, constipation, or ligament pain, and is commonly nothing to worry about. But in some cases, it can be a warning sign of something more serious - such as miscarriage, ectopic pregnancy, a UTI, and placental abruption. So, if you're pregnant and concerned about stomach pains, it's best to speak to your doctor or midwife for reassurance.
  • Heavy vaginal bleeding: Spotting or light implantation bleeding is common during the first trimester, but you should always speak to your doctor if you experience heavy bleeding from your vagina during pregnancy.
  • Severe dizziness: Dizziness that's caused by heat, hunger, nausea, or getting up too fast is usually just part of being pregnant. But if you're pregnant and often feel dizzy or become so dizzy that you faint, you should see your doctor. Dizziness or feeling faint can sometimes be caused by low iron levels or anaemia, which is a common side effect of pregnancy and can be treated by taking iron supplements prescribed by your GP or midwife.
  • Fever: A fever or high temperature above 37.5°C during pregnancy could harm you and your baby and needs immediate medical attention.
  • Itching that's worse at night: Some slight itching during pregnancy around your tummy is normal, but itching can also be a sign of a condition called intrahepatic cholestasis of pregnancy or ICP. You should speak to your doctor or midwife if you have itchy palms and soles of your feet that are worse at night.
  • Rash: You should seek medical attention as soon as possible if you're pregnant and spot any kind of rash, especially if you've been around someone with shingles or chickenpox.
  • Mental health struggles: Don't hesitate to seek support if you're pregnant and feeling depressed, anxious or like you can't to complete your usual, everyday tasks - especially if these feelings last for two weeks or longer.

Top tips for staying happy and healthy in early pregnancy

  1. Attend all your antenatal appointments: These appointments with your GP, midwife or obstetrician are really important. They allow them to check on the health of you and your baby, give you useful information, and answer any questions you may have along the way.
  2. Start prenatal vitamins: Once you find out that you're pregnant, you should take 400 micrograms of folic acid every day until the 12th week of your pregnancy. You should also take a 10-microgram vitamin D supplement once a day throughout your pregnancy.
  3. Get advice on safe prescriptions and medications: You should check with your pharmacist, midwife, or GP that any medication you're planning to take is safe to use during pregnancy before you take it. This includes anything prescribed by a doctor or purchased from a pharmacy or shop, including painkillers.
  4. Maintain a healthy diet: While it's totally ok to give in to your chocolate craving during pregnancy, it's important to stay hydrated and eat a balanced diet to support your baby's growth and to keep yourself feeling healthy.
  5. Keep exercising if you feel comfortable: Staying active during pregnancy is an excellent way to maintain your energy levels, boost your mood, and prepare for labour. It's safe for your baby, and if you feel comfortable, you can do light exercise throughout your pregnancy, unless you've been told not to exercise by a medical professional.
  6. Don't be afraid to advocate for yourself: Always speak to your healthcare provider if you have any concerns or questions about your health, your pregnancy or your baby's development.

When does the first-trimester end?

The first trimester ends in the 12th week of pregnancy.

It's important to remember that every pregnancy is unique, and individual circumstances may require unique precautions, so it's always best to consult with your healthcare provider for personalised advice based on your specific situation.

As a general rule, however, it's important to be cautious during the first trimester of pregnancy and avoid certain things that could potentially harm the developing foetus, such as:

  • Alcohol
  • Smoking
  • Illicit drugs
  • Certain medications: Consult with your healthcare provider before taking any medication during pregnancy
  • Caffeine: Limit caffeine intake to 200 milligrams per day
  • Raw or undercooked foods
  • Certain fish that contain high levels of mercury
  • Cat litter: This can carry a parasite that causes toxoplasmosis which can be dangerous for your unborn child, so it's best to avoid handling it when you're pregnant

The first trimester lasts for three months.

We asked our Instagram followers what the first trimester felt like for them, and here's what they told us:

  • "I had zero symptoms apart from lack of period."
  • "Struggling with food aversions and sickness, while trying to act normal."
  • "The longest! Because you're keeping it quiet, but you want to explode and tell the world."
  • "Like I've got a little secret."
  • "Emotional and overwhelming."
  • "Mine was good, felt very hungry all the time."
  • "A real out of body experience, didn't feel like myself one bit."
  • "Tired and constantly feel sick but not being sick. Smells were triggering."
  • "Nausea, constantly hungry, always sleepy."