Your one-stop guide to the first trimester

If you’re in the first trimester of pregnancy, you’ve embarked on one of the most remarkable and daunting adventures of your life. It is natural to have several questions and doubts about what’s in store for you. So, we have put together a guide below to help you become better prepared for the first trimester and make informed decisions about your and your baby’s health. 

What is the first trimester?

A pregnancy is considered to be 40 weeks long on average. The weeks, in turn, are clubbed into groups of three months known as trimesters. 

A pregnancy has three trimesters: 

• The first trimester comprises the first 12 weeks of pregnancy, i.e., from Week 1 (egg fertilization/conception) to the end of Week 12

• The second trimester is from Week 13 to the end of Week 26 

• The third trimester is from Week 27 to the end of Week 40 or the end of your pregnancy

Your body will go through several changes during the first trimester. You could have concerns such as:

• How to keep your baby safe and well-nourished

• What to eat and what to avoid

• Which prenatal tests to consider 

• How to minimize or alleviate pregnancy symptoms

• How much weight you could gain

Knowing how a pregnancy progresses week by week can help you be better prepared for the changes and challenges that you may face during your pregnancy.

Pregnancy symptoms in the first trimester

In the first trimester, changing hormone levels will affect your entire body. One of the early signs of pregnancy that all women experience is a missed period. 

Other early pregnancy symptoms that you could experience in your first trimester are as follows:

• Tender breasts 

• Mood swings

• Heartburn

• Nausea or vomiting/morning sickness

• Frequent urination

• Weight loss or gain

• Extreme fatigue or tiredness

• Headaches

• Pelvic and lower-back pain

• Leg cramps

• Food cravings and aversions

• Constipation or upset stomach

To manage these first trimester pregnancy symptoms, you may need to change your eating, sleeping, and work habits. You could also not experience any of these symptoms during your pregnancy.

Baby development in the first trimester 

The first trimester is the most important period for your baby’s development. During this period, your baby’s body parts and internal organs start to form, such as:

• Brain 

• Spine

• Cardiac tissue

• Lungs

• Liver

• Kidneys

• Pancreas

• Genitals

• Inner ear

• Eyelids

• Mouth, nose, and eye muscles

• Cartilage in the limbs and appendages

• Fingernails

• Webbed toes and fingers

When you’re in the first trimester, by the end of Week 4 (1 month) your baby could be the size of a poppy seed, i.e., around 0.25 in. By the end of Week 12 (3 months), your baby could grow to be the size of a lime, i.e., around 4 in.  

Learn more about your baby’s development in the first 4 weeks of the first trimester. 

Tips to relieve pregnancy symptoms in the first trimester

Early pregnancy symptoms can cause you pain and discomfort. Here are some tips that could help ease some of the problems that you may experience in the first trimester:

• For breast pain, wear comfortable maternity bras 

• For morning sickness, eat small meals, avoid fried foods, try ginger and chamomile tea, and take vitamin B6

• For leg cramps, take magnesium or calcium

• For constipation, switch to a high-fiber diet and take fiber supplements like wheat bran

• For fatigue, take ample rest or short naps throughout the day 

• For frequent urination, don’t hold in your pee, go whenever nature calls, and stay hydrated

Remember to consult your Doctor before making any changes to your lifestyle or diet. 

If the pain or discomfort persists and cannot be managed with the home remedies, check with your Doctor for another alternative, such as an over-the-counter pain reliever.

How to stay healthy during the first trimester

Knowing the pregnancy dos and don’ts can help you take better care of yourself and your growing baby. 

Things that you should do during the first trimester:

• Take prenatal vitamins

• Exercise routinely

• Do pelvic floor workouts, such as Kegel exercises

• Eat lots of fruits, vegetables, high-fiber foods, and low-fat protein

• Drink plenty of water

• Eat an extra 300+ calories 

Things that you should avoid or quit during the first trimester:

• Strenuous exercise or strength training (could injure your stomach)

• Alcohol and illegal drugs 

• Caffeine 

• Smoking

• Raw or smoked seafood

• Fish with high levels of mercury, such as swordfish and mackerel

• Raw sprouts

• Cat litter (could cause toxoplasmosis)

• Unpasteurized milk and other dairy products

• Hot dogs or deli meats 

Learn more about the first trimester diet tips.

Sex during the first trimester

Pregnancy symptoms like extreme fatigue, headaches, and nausea can put you off sex. However, if you're in the mood and the Doctor has not advised against it due to some complication, you can go ahead and have sex as it won’t hurt your baby. Your baby is protected by:

• Amniotic sac 

• Strong uterine muscles 

• Mucus plug 

Know more about having sex during pregnancy.

Pregnancy checklist for the first trimester 

Use the following list to keep a track of all the first trimester tasks that you may need to perform: 

• Take prenatal vitamins

• Check your health insurance

• Select a Doctor if you don’t have one already

• Book a prenatal appointment

• Get to see or hear your baby for the first time

• Run your medications past your Doctor

• Quit unhealthy and unsafe habits such as avoiding caffeine

• Check if you need prenatal testing

• Plan how to announce your pregnancy

• Start taking photos of your belly 

• Track your baby's development

Learn about other pregnancy dos and don’ts.

Not sure where you are in your pregnancy?

As mentioned earlier, the first three months of your pregnancy (weeks 1-12) constitute the first trimester. If you are not sure what week of pregnancy you are in, you need to first calculate your expected due date. 

You can get this done at the Doctor’s or you can use our free Due Date Calculator tool. 

When to see a Doctor

Once you find out that you’re pregnant, see your Doctor so that he/she can provide you appropriate care for your developing baby, starting with the consumption of prenatal vitamins with folic acid (if you’re not taking it already). 

In the first trimester, you could visit your Doctor once a month for prenatal checkup. During your first check-up, your Doctor could do the following:

• Note down your complete medical history 

• Perform a full body and pelvic examination 

• Confirm the pregnancy using ultrasound

• Perform a Pap test

• Measure your blood pressure

• Test for sexually transmitted infections such as HIV and hepatitis

• Calculate your expected due date 

• Screen for risk factors such as anemia

• Determine your thyroid levels

• Measure your weight

You can consult your Doctor about whether you should go for genetic screening at this stage. Genetic screening determines if your baby is at risk of developing some specific genetic diseases.

Learn more about the important pregnancy tests performed in the first trimester. 

Other things to watch out for in the first trimester

Reach out to your Doctor if you experience any of the following symptoms in the first trimester:

• Severe cramping

• Severe vomiting

• A fever of 38° C (100° F) or more

• Foul-smelling vaginal discharge

• Painful urination

• Vaginal bleeding

If you have any more questions or concerns about pregnancy and the first trimester, feel free to ask our Doctors for advice