Pregnancy Trimester 1

Pregnancy Trimester 1

Here we discuss Pregnancy week 4 to week 8 and Pregnancy weeks 10 to 12. Click on the links below to read about the weeks that are important to you.

First Trimester: Pregnancy Weeks 4 – 8
First Trimester: Pregnancy Weeks 10 – 12

You may also find some of the suggested readings helpful at this time.
You may also like to watch our youtube video showing week by week fetal development of your baby – it makes it all so much more real when you see what is likely to be happening inside your womb!

First Trimester: Pregnancy Weeks 4 – 8

What to expect when expecting:
First Trimester Pregnancy Weeks 4-8
Growing a healthy baby inside you:
A time when pregnancy morning sickness affects approximately 70% of pregnant Moms/Moms-to-be
This is the crucial time for formation of some of your baby’s organs and you will want to stay away from substances/agents that can cause damage to your baby eg alcohol. To read more about alcohol during your pregnancy. Go to the parenting insights at the bottom of this page.

You’ll want to know the week by week fetal development of your baby and just get used to the fact that you are pregnant!!   You’ll be deciding who you will share that information with.   You’ll be searching the pregnancy websites looking for pregnancy facts and finding out what you can to help make your baby healthy.

This is the time to see your Doctor or Midwife, to confirm your pregnancy and find out what else you need to do, get information on pregnancy and nutrition (see our Nutritionist tips below).   They will also guide you on what nutritional supplements may be helpful and it will be up to you to follow a healthy diet for pregnancy.
You’ll want to stay away from people who have contagious diseases, such as Rubella (German measles), colds and flu’s.

Diseases that can cause miscarriage or damage to your baby include:
TOXOPLASMOSIS – this is caused by a parasite and is found  particularly in the soil and faeces (pooh) of animals, especially cats.
•    Make sure you cook your meat thoroughly
•    Wash your hands after handling meat
•    Wash all vegetables thoroughly before eating or cooking
•    Wear gloves if handling litter trays, gardening etc
•    Avoid contact with cats if possible

CYTOMEGALOVIRUS –  a virus from the Herpes family.  Varicella zoster (Chicken Pox), Herpes Simplex which causes cold sores, and Glandular Fever (Epstein-Barr) – are all related viruses.
This virus is spread through the air, and blood contact, urine or faeces, mucous membranes in the mouth and also via the genital organs.

LISTERIOSIS – caused by a bacteria which exists in the soil.
•    Avoid unpasturised soft cheeses (Brie and Stilton), basically all soft cheeses, processed meats, ready made salads, and undercooked chicken.

•    Gonorrhoea
•    Syphilis
•    Genital Herpes
•    HIV/Aids
•    Chlamydia

It is important that you protect yourself during sex – if your partner has any of the above, as they can affect your baby.   Speak to your Doctor/Midwife if you are unsure, and in most countries there will some screening during your pregnancy for some of the above diseases
The other big danger to your baby is XRAYS – particularly during pregnancy first trimester.   TELL THE PERSON DOING THE TESTS – BEFORE THEY START!!!

Possible Effects on You

•    Sore or tender breasts
•    Needing to go to the toilet frequently
•    Some queasiness
•    Tired or exhausted
•    Dizziness or fainting
•    No period – that at least is a bonus
•    Absolute disbelief that YOU ARE PREGNANT

Week by week fetal development

4 Weeks pregnant – the tiny being is smaller than a grain of rice
5 Weeks pregnant – neural tube developing which eventually becomes the brain and spinal cord
6 Weeks pregnant – Embryo 3mm in length
7 Weeks pregnant –  the heart starts to beat;  embryo has it’s placenta (which becomes the afterbirth) and the amnio sac.   The placenta attaches to the wall of the uterus (womb) to get oxygen and nutrients for your baby-to-be!
8 Weeks pregnant – Embryo 1.3mm (about 1/2inch).   The spinal cord looks like a tail and the head is very large compared to the body

First Trimester: Pregnancy Weeks 10 – 12

Your pregnancy 10 weeks to 12 weeks is a crucial time, when tests are done to determine the likelihood of your baby being born with inherited diseases or chromosome abnormalities.

Possible Effects on You:

Chances are you are still suffering from pregnancy morning sickness, and feeling exhausted a lot of the time, breasts are still tender and growing bigger every day, and you’re still visiting the toilet frequently.   Depending on how much you’ve been able to eat – you may or may not be putting on weight.   If you have not yet checked out the alcohol pregnancy section – now is a good time to do that.

You are likely to be

  • sensitive to heat
  • developing a “linea nigra” – a dark line from below your navel (belly button) to your pubic area
  • By 12 weeks of pregnancy – the uterus (womb) is high enough in the pelvic area – so the pressure on your bladder is relieved – and you don’t need to go to the loo quite so often.
  • The uterus can be felt just above your pubic bone
  • This is a very emotional time, waiting to do tests that will determine whether your baby-to-be may be at risk of being born with inherited (genetic challenges) or abnormalities.   It is great if there is someone around to support you at this time.
  • Not everyone is excited about being pregnant – having a baby is going to have a huge impact on your life – and you are beginning to realise this.
  • How will you be able to afford to have your baby – to give your baby the best possible – because I know that is what you want for your baby.

By the time you are 10 weeks pregnant – you have usually visited your Doctor/Midwife or Health Care Professional and they will have advised you to have a blood test to check

  • Your “Rubella” status which means whether you have had German Measles or not.   Rubella infection can be extremely dangerous for the developing foetus, can lead to severe birth defects – such as blindness, deafness, heart problems, inflammation of lungs, liver, or brain.   There can also be severe mental retardation.   If you do not have Rubella antibodies -you need to avoid exposure to Rubella, and you would likely be advised to be immunised after your baby is born – so that you are not at risk in future pregnancies.
  • Blood count – checking red blood cell counts for anaemia, white blood cells to see how healthy your immune system is, and platelet count – which are involved in blood clotting.   Your iron levels may also be done, and usually you are advised to take iron supplements (best taken with orange juice for absorbtion), and to increase food intake of foods containing iron. See our Nutritionist’s guide to pregnancy and nutrition.
  • Blood Group and Rhesus (Rh) status:   We all belong to a blood group A, B, AB or O and we are all either Rhesus Positive or Negative.    What they are looking for here – is for Rh Negative Mums-to-be.   If their baby is Rh Positive – the Mum will develop antibodies to her baby’s blood cells, which means the baby’s blood cells may be destroyed.   Unless the Mom has had a previous miscarriage – this is not likely to be a problem in the first pregnancy – but the levels of antibodies will be monitored – again in the third trimester, and an injection of Rh immuno-globulin (anti-D) will be given at 28 and 34 weeks of pregnancy.   If the father of the baby is also Rh Negative – the baby will be Negative as well – so there will be no problem for the baby.
  • Generally a test for HIV/Aids is included in normal pregnancy screening – unless you specifically ask for the test not to be done.   It is in the baby’s best interests to know whether you are HIV positive, as your Doctor can reduce the risk to your baby – by using antiviral drugs and by delivering the baby by Caesarian Section.
  • Hepatitis B status – if it is Positive – your baby can be given a vaccination after birth
  • Syphilis – very unlikely these days, and easily treated with antibiotics – though untreated causes serious problem with your baby’s brain development.

Ultrasound and other Diagnostic Tests:

You may not know why your Doctor/ Midwife/ Health Care Professional is suggesting you have all these tests.   The reason is that many of the tests are able to detect whether your baby has a severe deformity (unfortunately lesser defects may not be picked up) or inherited (Genetic) problems.   In most countries – if there is a choice to take away (abort)- the pregnancy – it is best done before 16 weeks, in fact the earlier the better.   You may say you would never have an abortion – but the tests are still extremely helpful – in helping you prepare, and in some cases there may be ways that the Doctors can make things easier for the baby, before it is born), but the choice is always yours.   Nature’s way of dealing with babies/embryo that are not developing normally – is to miscarry – but miscarriage doesn’t always happen and the pregnancy continues.   That is where Ultrasounds and other diagnostic tests come in.

Ultrasound (roughly 11 -12 weeks pregnancy):
This is a very emotional time – because you are able to see your little baby – possibly see some movements – the baby is no longer called an embryo – but a foetus (fetus if you are from North America).

  • Ultrasound is done by a Specialist
  • It is completely painless – sound waves send back pictures of your baby, or babies!!  Information on how the baby is growing, where the placenta (afterbirth) is, how much fluid is surrounding the baby etc
  • Is done either via the abdominal wall just above your pubic area – or can be done by placing a probe into your vagina (fanny) – the Specialist will tell you which way is best so that he can get the best pictures of your baby
  • The Specialist will be looking out particularly for signs of Down’s Syndrome – or nuchal translucency.
  • The Specialist may be able to see whether your baby is a boy or girl (but I have known them to be wrong!!)

Chorionic Villus Sampling (CVS) and Amniocentesis and Fetal blood sampling (Diagnostic tests done if your Doctor thinks you at greater risk of your baby being born with an inherited defect or chromosome abnormality eg Down’s Syndrome (called Trisomy21).    The CVS is done at about 11 weeks, via the vagina (fanny) or through the abdominal wall.   Some of the cells from the placenta are collected and sent to the laboratory for analysis.   The risk of miscarriage increases very slightly – and figures out now seem to show the risk at about 1/1000 .   Any extra test can be stressful – so do what you can to ensure you will have some support at or after the test. More expensive DNA test results are available in a few days, or you may have to wait a few weeks.

Other possible tests include:

  • Amniocentesis – discussed at 16 weeks of pregnancy
  • Maternal Serum alpha-fetoprotein – discussed 16+ weeks of pregnancy
  • Fetal Blood sampling –  discussed at 18- 20 weeks pregnancy


This is one of the most important choices you will make.   You need to know that you and your baby will be safe and that you have confidence in your decision.

Depending on which country you live in, if you have a “low risk pregnancy” you will be able to choose between a hospital or home birth.   In some countries you may need to go into hospital for the actual birth – and then return home 24 hours later.
It is very important that you start researching these as soon as possible, as often if you leave it too late – not all choices may still be available to you.

Here are some pregnancy websites that help you explore your options:

Your baby at 12 weeks pregnancy:

Your baby is fully formed, the toes and fingers have separated, the head is more in proportion to the body.   Actual size is about 61mm or 2 ½ inches.
All the organs will continue to develop and particularly the brain and nervous system.   Amazingly, as the pregnancy continues, the brain cells, neurons, become sensitive to the hormones in the Mom’s blood, particularly the stress hormones, and even the environment (what is going on in the Mom’s life) affects the way your baby’s brain develops and will impact your baby’s behaviour and coping abilities later in life.
More on this in 20 weeks of pregnancy/stress hormones effect on your baby.