1st Trimester of Pregnancy

1st Trimester of Pregnancy

Pregnancy is divided into 3 trimesters and the 1st trimester is the first 3 months.

In this section we will look at pregnancy development and how you may feel during the 1st trimester

First trimester of pregnancy can be overwhelming. By understanding what is happening in your body and some of the changes you may experience will help you take care of yourself during this exciting time.

The fertilized egg develops inside a water filled amniotic sac. This water filled sac helps to protect and cushion the growing embryo throughout pregnancy.

The placenta also develops in the first trimester. The placenta appears round and flat. It transfers nutrients from the mother to the baby, and transfers waste from the baby.

A face begins to develop with large dark circles for eyes. The mouth, jaw, and throat are developing. Blood cells are taking shape, and circulation will begin.

By the end of the first month of pregnancy, your baby is around 6-7mm (1/4 inch) long – about the size of a grain of rice.

During the second month of pregnancy your baby’s facial features continue to develop. Each ear begins as a little fold of skin at the side of the head. Tiny buds that eventually grow into arms and legs are forming. Fingers, toes, and eyes are also forming in the second month of pregnancy.

The neural tube (brain, spinal cord, and other neural tissue of the central nervous system) is well formed. Bone starts to replace cartilage. The digestive tract and sensory organs begin to develop. The embryo begins to move, although the mother will not be able to feel it yet.
By the end of the second month, your baby is about 2.50cm (1 inch) long, weighs about 9.45g (1/3 ounce), and the baby’s head is the biggest part making up about a third of the baby.

By the end of the third month of pregnancy, your baby is fully formed. Your baby has arms, hands, fingers, feet, and toes and can open and close its fists and mouth. Fingernails and toenails are beginning to develop and the external ears are formed. Teeth are forming. Your baby’s reproductive organs also develop. The circulatory and urinary systems are working.

At the end of the third month, your baby is about 7.6 -10 cm (3-4 inches) long and weighs about 28g

What to expect in the First Trimester of Pregnancy

You may not look pregnant yet, but chances are you’re feeling it.

The first trimester of pregnancy is an amazing transformation and it happens very quickly.

Knowing what changes to expect during the first 3 months can help you face the months with confidence.

Remember everyone is different so you may not experience the same symptoms as your friend or sister.

Here are some of the common physical changes during the first trimeste.


Morning sickness, which can happen at any time of the day or night, sometimes begins as early as three weeks after conception. The hormones oestrogen and progesterone are rising rapidly and results in the stomach emptying more slowly and this can cause nausea. Pregnant women also more sensitive to smell, so various odours can cause waves of nausea in early pregnancy.

You can help yourself by eating small meals, snack frequently. Make sure your diet is low in fat and easy to digest. Avoid foods or smells that trigger your nausea and drink plenty of liquids.

Motion sickness bands are helpful. Alternative therapies such as acupuncture or hypnosis offer relief but you must consult your health professional before you consider alternative therapies.

If you are unable to keep liquids down you need to contact your health professional for advice.

Breast Tenderness

Hormonal changes in early pregnancy might make your breasts tender, sensitive or sore. Wearing a more supportive bra might help.

Passing Urine Frequently

You might find yourself urinating more often. The growing uterus can cause pressure on your bladder which can cause you to leak some urine.

If you’re losing sleep due to frequent trips to the toilet, you may need to cut back on your fluids late in the evening.


Tiredness / Fatigue is very common in the first trimester of pregnancy. Progesterone levels are rising rapidly and it can make you very tired.

It is impossible to fight this tiredness so listen to your body and rest as much as you can. Include some physical activity, such as a walk, in your daily routine.

When you’re pregnant, you might find yourself disliking certain foods. Food cravings are common, too. Like most other symptoms of pregnancy, these food cravings can be blamed on the rising hormone levels also especially in the first trimester, when hormonal changes are the most dramatic.

Pregnancy causes your blood vessels to dilate and your blood pressure to drop, which might leave you lightheaded or dizzy. To help prevent these symptoms, avoid prolonged periods of standing. Get up slowly after lying or sitting down. If you’re standing when dizziness hits, lie down on your left side.

Constipation and Heartburn

Pregnancy slows the movement of food through your digestive system. This allows nutrients more time to be absorbed into your bloodstream and reach your baby. However, it can also result in constipation. Pregnancy hormones causes the valve between your stomach and oesophagus to relax and this results in acid from your stomach leaking into your oesophagus, causing heartburn.

To help relieve the symptoms of heartburn, eat small, frequent meals and avoid fatty foods, fizzy drinks, juices, and spicy foods. To prevent or relieve constipation, include plenty of fibre in your diet and drink lots of fluids. Exercise also helps.

Your Emotions / Feelings and your Partner

Pregnancy is a very emotional time and while you are very excited you might also be anxious and exhausted. No matter how excited you are, a new baby adds emotional stress to your life.

You may be worried if everything is normal with your baby and wonder how you are going to adjust to becoming a mother, you may even worry about the extra financial demands on you and your partner. You may be worried about your career and how you will continue working and caring for a baby as well.

It is very common to feel upset and experience mood swings. Remember your feelings are normal. Look after yourself and talk to your partner about how you are feeling. Encourage your partner to share any worries. You need plenty of encouragement and support just now. Discussing your feelings will strengthen your relationship and help you begin preparing for your baby.

Antenatal Visit

Your first visit will focus mainly on your health history where your midwife or doctor will ask you lots of questions from your antenatal chart. They will be looking for any risk factors and an ultrasound scan is usually carried out at this visit to assess if your dates are correct and check how many babies are in your uterus. An accurate history will help you and your baby receive the best care. You will also have routine pregnancy blood tests carried out and your blood pressure recorded.

After the first visit, you will probably have antenatal check-ups every four weeks. During these appointments, talk to your midwife or doctor about any concerns you may have. Remember, no question is silly or unimportant. It is important that you take care of yourself and your baby.


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