An overview of the stages of pregnancy
When a pregnancy is full-term, it means that it lasts 40 weeks, this is the duration of the typical pregnancy, which is dated from the date of conception (typically the last day of your most recent period) to the day of giving birth. This period of time is divided into three stages, known as trimesters. These trimesters are as follows: the first, second and third trimesters, with each one lasting between 12 to 14 weeks (about three months). Each trimester comes with its own symptoms due to hormonal changes as well as different physiological developments and changes.
It is good to know how your baby and your body are developing as the pregnancy progresses as this will help you to be prepared and equipped for the upcoming months, it is also best to know about the specific risks and other factors associated with pregnancy trimesters.
The following article explores an overview of what you need to know about the miracle foetus growing inside of you. Please note that this article is intended for informational purposes only and not as a professional medical opinion, it is best to consult with your doctor for that.
The stages of pregnancy explored
The first trimester
Your first trimester is from the day of conception (or the last day of the most recent period) to week 12 of the pregnancy. Your body starts to change rapidly as it prepares to have a baby. Your hormones are likely to change every organ and system in your body. At times, it might feel like your body is out of your control as symptoms begin to trigger in the first few weeks of pregnancy, potentially bringing with them fatigue, headaches, morning sickness and constipation.
Your uterus changes to support the growth of a foetus and the growth of the placenta as your body starts to increase blood flow, oxygen and nutrient supply to the developing foetus.
Your heart rate will also increase in order to aid in the development of the baby. With these changes your doctor may recommend that you take supplements containing folic acid which help prevent birth defects such as brain disorders or issues with the baby’s spinal cord. It is important to remember that the first trimester is the most important for the baby’s development. Your baby is likely to develop all of its organs at the end of month three, thus making this period a crucial step for the baby’s growth.
It is advised that you stick to a healthy diet advised by your doctor. Do not smoke cigarettes or drink any alcohol, these substances are harmful to the developing baby.
First trimester tests
Your first test during this trimester is likely to be an at-home pregnancy test which tells you if you are pregnant or not. If you are, you will consult with your doctor, this should be at about six to eight weeks after your last menstrual period. Your doctor will confirm your pregnancy through a blood or urine test, either of these being your second test.
Your doctor will then use a Doppler machine or perform an ultrasound to check the baby’s health and heartbeat. He may also take blood samples to check your immunity and nutritional levels.
Be sure to speak to him/her about medical history, genetic issues or any other risk factors you may have that could put the baby at risk.
First trimester risks
Your risk of a miscarriage is at its highest in the first trimester for a number of reasons, and oftentimes the exact cause cannot be identified but chromosomal abnormalities are usually the most common cause.
Your doctor may advise you to avoid caffeine, shellfish and deli meat as these can contain harmful bacteria to the baby. By doing this, you will be decreasing the chances of miscarriage. It is also vital that you keep your doctor informed about all changes your body is going through, specifically ones that you feel may be abnormal.
Your doctor is likely to advise that you wait until you are in your second trimester to tell people you are pregnant, with the first trimester being the riskiest for the baby’s survival.
The first trimester gives you the chance to think about topics such as breastfeeding, parental classes and learning more about childbirth.
First trimester emotional and physical changes
Your first change that you will notice is that you will miss your period. There are however other changes that are also likely to occur, although these will differ from woman to woman:
- Swollen and tender breasts
- Morning sickness
- Food cravings and aversions
- Weight loss or weight gain
- Frequent urination
- Mood swings
First trimester routine changes
As your body starts to change and adapt to the baby inside of it, you may also deem it necessary to change your daily routine. You might find it better to go to bed earlier, change your diet, and eat smaller, more frequent meals. Most of the symptoms you are experiencing are likely to go away or become less intense as your pregnancy progresses. Every woman’s experience of pregnancy is different, your symptoms and reaction to it may be different to another woman’s.
First trimester baby growth at four weeks
At week four your baby is starting to grow and develop in the following ways:
- The heart has started to form
- The baby is about 0.6cm long
- The baby has started to grow arm and legs buds
- The spinal cord and brain have begun to form (the nervous system)
First trimester baby growth at eight weeks
At eight weeks, your baby begins to develop from an embryo to a foetus, which means the following has begun:
- The major organs have started to form
- The heart has started to beat
- The buds of the arms and legs are now growing longer
- The baby’s face has started to form features
- The fingers and toes have started to grow
- Your baby is now nearly 2.5cm long
- The sexual organs have started to grow
- The umbilical cord is now visible
First trimester baby growth at twelve weeks
The first trimester ends around week 12, at this time your baby is starting to develop and grow the following:
- The muscles and nerves start to work together – the baby is now able to form a fist.
- The external sex organs have formed and you can tell what sex the baby is (if you want to know 😉)
- The eyelids will now close in order to allow the eyes to develop and be protected
- They will only open again in the 28th week
- The baby is about 7.6cm long
The second trimester
The second trimester is from week 13 to week 28. This is often the most comfortable time of pregnancy for most women. The early symptoms of the first trimester will start to disappear here and you are likely to feel a boost in energy levels and a better night’s sleep.
You will start to show that you are pregnant in your abdominal area as your uterus starts to rapidly grow. It is advised that you stop wearing tight clothing and invest in looser, more comfortable maternity wear. This is also the safest time to spread the great news that you are pregnant to family and friends.
This period does, however, some with a few new symptoms such as heartburn (which you may have already experienced if you’re in this phase of pregnancy), and leg cramps. You might also have more of an appetite, but be careful not to gain unnecessary weight here, try walking regularly to also ease the leg cramps and keep off the unwanted weight. Stick to nutrient-packed foods and make sure your doctor monitors your weight gain. You may also experience backaches (this is because of the ligaments being softened and extra weight of the growing baby which can change your posture), varicose veins (due to estrogen and progesterone being known to deteriorate the inner lining of the veins, making then weaker and thinner) and nasal congestion (hormones are causing the lining of the nose to weaken and swell).
This is also a very exciting period as you are normally able to feel your baby move around for the very first time.
This usually occurs at about 20 weeks. Your baby can start to hear you now.
Second trimester tests and risks
Your doctor may perform some screening tests on you.
An anatomy ultrasound is typically performed between 18 and 22 weeks. Here, the baby’s body parts are measured and evaluated in order to ensure they are growing and functioning correctly.
The list of body parts doctors evaluate when looking at your developing baby are as follows:
You are most likely to also find out the exact sex of the baby here if you were unable to do so in the first trimester. Your doctor is also likely to test for gestational diabetes at this stage, this can be detected between 26 and 28 weeks. For this test, you are instructed to swallow a substance that is high-glucose, after which you will have to wait an hour before having your blood drawn. Your blood is then tested to see if your body reacts correctly to sugar during pregnancy.
Second trimester emotional and physical changes
Any morning sickness you may be experiencing tends to lessen in the second trimester. You may notice other changes such as the typical baby bump starting to form nicely now.
However, symptoms of the second trimester can include:
- Bodily aches in the groyne, abdomen or legs
- Your areola (area around the nipples) darkening
- Stretch marks may start to form on your breasts, thighs, bum and belly
- A line of skin starting from the pubic hairline to the belly button may form (linea nigra)
- Unusual patches of dark skin on the forehead, upper lips, forehead and nose (known as Chloasma, Melasma and even “the pregnancy mask”)
- Tingling or numb hands
- An itchy abdomen and feet
- Feet may start to swell, as well as fingers and the face
Second trimester baby growth at sixteen weeks
Your baby will continue to grow and develop, these changes are as follows:
- Your baby’s musculoskeletal system will continue forming
- Your baby will start to develop its sucking reflex
- Your baby is about 10 to 12cm long
- Your baby will have its first bowel movement as meconium develops in its intestinal tract
- Your baby’s skin will start to form and be quite translucent
Second trimester baby growth at 20 weeks
Your baby will continue to develop in the following ways at 20 weeks:
- You baby will start to be more active in kicking and moving
- Your baby will now be covered by lanugo, which is a fine and feathery hair coat as well as being covered in vernix, which is a waxy coating
- Your baby can now swallow and hear
- The toenails, eyebrows, fingernails and eyelashes have now formed (your baby can also scratch itself now)
- Your baby is about 15cm long
Second trimester baby growth at 24 weeks
At 24 weeks, your baby is undergoing, even more, changes, these being:
- Your baby has formed taste buds on its tongue
- Your baby’s bone marrow has started to create blood cells
- Fingerprints and footprints have formed
- Hair has started to grow on the head of your baby
- The lungs do not work but have been formed
- Your baby now has a regular sleep pattern and cycle
- Depending on the sex of the baby, their sexual organs are now formed and in place
- The baby is now about 30cm long
The third trimester
Congratulations, you have reached the homestretch. The third trimester lasts from week 28 to week 40, which is normally the time of birth. You will now start to see your doctor on a more regular basis as monitoring during this stage is vital. You are likely to be going to the toilet more and more now and may even have difficulty breathing as the baby presses on your diaphragm. The baby is getting bigger and bigger, resulting it in pushing on some of your organs, usually your lungs and bladder. These signs are normal and healthy.
Third trimester tests and risks
In seeing your doctor more frequently now, he/she is likely to conduct tests on and assess the following:
- Urine tests for protein
- Blood pressure tests
- Measurement of uterine growth
- Checking legs and hands for swelling
- Checking the baby’s position in the cervix ensuring that it is correct for birth
You may also be screened for Group B streptococcus bacteria. This involves taking a swab sample from the vaginal region and sending this to a lab to be tested. If this bacterium is found it is a severe threat to the baby as it is passed through the vagina during delivery. If you do have this bacterium, your doctor will prescribe antibiotics to get rid of it.
Your doctor will also inform you about travel restrictions and advise that you stay close to him/her or your chosen midwife as you get closer to your due date.
Cruise ships and airlines do not typically allow women that are over 28 weeks pregnant to travel.
It is best that during this time you know about the stages of labour and what the options for delivery are. Ask your doctor about any questions you may have in order for you to feel comfortable about the birth of your baby.
Third trimester emotional and physical changes
The discomforts that you felt in the second trimester are likely to worsen in the third trimester.
Other changes are likely to be any of the following:
- Haemorrhoids may start to develop
- Your ankles, face and fingers may experience swelling
- Breasts may be tender and may also leak a milky discharge
- Your belly button can start to protrude
- You may start to experience contractions which can be real or false labour signs (Braxton Hicks)
- Your baby will start to drop or move lower in the abdomen
- You may also have heartburn, shortness of breath and difficulty sleeping as you feel uncomfortable
Third trimester baby growth as due date gets closer
Your cervix starts to thin and become softer as your due date approaches, this process is known as effacement and aids in your cervix opening for childbirth. Your doctor will monitor your internal changes with regular exams and testing.
Third trimester baby growth at 32 weeks
Your baby will continue to develop in the following ways:
- Your baby’s bones are fully formed but soft
- The lanugo hair layer will fall off
- Your baby grows rapidly
- The body of your baby will start storing important minerals such as calcium and iron
- Your baby’s eyes can open and close
- The lungs, not being fully formed, still start to practise the breathing motion
- Kicking and movement is increasing
Third trimester baby growth at 36 weeks
Your due date is now fast-approaching, and with this, your baby is developing in the following ways:
- The baby’s body fat is increasing
- Your baby, now being bigger, will not be able to move as much inside of you, the movements are often more rigid, but you will still feel them
- The vernix layer of waxy coating is now thickening
- Your baby is about 40 to 48cm long
Third trimester baby growth at 37 to 40 weeks
This is it. All the waiting, sleepless nights and researching is going to soon be worth it. In the final stages of your pregnancy your baby is undergoing the following changes:
- Your baby has now fully grown
- Your baby’s organs have developed fully and can function on their own
- If all goes according to plan, your baby’s head will now move to the head-down position for the birth
- Your baby is about 48 to 53cm long
Keep in mind that all babies are born with different weights and sizes. Your doctor will be able to inform you about what a healthy size and weight is.
The due date
It has been quite the ride up until now. As an expecting mother, you are probably excited and nervous to meet your new-born baby. Your due date, however, is not always accurate and is more of an estimated date of delivery, being known as an EDD. The system that works out the date of your baby’s birth is often more reliable with women who have regular menstrual cycles.
The most accurate way of finding out when your baby will be born is during an ultrasound in the first trimester. This gives the doctor a good understanding of the size of the baby which indicates its age.
How you want to give birth is entirely up to you. It is a very personal decision and should be made between you and your doctor as he/she will know what is best for you medically and will advise accordingly so that you can make an informed decision on having a natural birth or whether a C-section will be required for medical reasons or be an elective procedure.
On a final note
Pregnancy is not like anything you have ever experienced. Your body will go through major changes. It is always best to get the support and guidance of your doctor and of course your family and friends. Make sure you are making decisions that are best for you and your baby, such as sticking to a healthy diet and lifestyle and taking prenatal vitamins, as well as seeing your doctor on a regular basis and undergoing all the tests that are recommended to you. Prepare for the ride of a lifetime.
If you want to know all about the stages of your pregnancy, then read our article on the first trimester as we cover each week in detail.
This article on your second trimester of pregnancy will cover everything you need to know on a week-to-week basis...
Your third and final trimester is the most exciting one because at the end of it all, through all the symptoms, you should be walking away with a healthy little baby...