Stages of Pregnancy
An overview from conception to birth
Introduction
This information has been prepared for you in consultation with midwives and current health care findings. The information is meant to be used as a general guide only (please read the disclaimer at the end). Note that all pregnancies are different and you should always consult with your carer if you have any concerns.
One of the wonderful things about the nine months of pregnancy is that you have time to come to terms with the transition your life is about to make. As your body slowly changes week by week, your mind also starts to come to terms with what is happening. While it is good to feel awe at the magnitude of what is happening, it is also important to remember that pregnancy and birthing is a very natural thing and we, as a race, have been doing it very well for many years now! So if possible try to approach your pregnancy with an open mind. Let go of any fears or misgivings and try to surrender to the most natural of things – you’ll be amazed at what a wonderful experience this can be.
First Trimester
The time we discover we are indeed pregnant! We have our first visit to the doctor, the pregnancy test, and lots of contemplation. For many women this stage is one of great discomfort as morning sickness strikes and seems to go on forever.
The first twelve weeks of pregnancy are the most vital as this is when your baby will take on the human form and the brain, heart, nervous system, backbone and face will begin to develop. If you have been planning to get pregnant or if you suspect that you are, it is very important that you take great care with prescriptions, alcohol, chemicals and so on. Try to eat healthy foods and maintain a balanced diet.
Pregnancy is usually calculated from the first day of your last menstrual period. Your baby was not conceived then but ovulation is assumed to have occurred about thirteen or fourteen days later. Therefore at the beginning of the third week of pregnancy you have one tiny fertilized egg.
3rd Week
Baby’s Development - The conception and the beginning. The ovum becomes fertilized and divides. The ripe egg released from the ovary divides into two cells a few hours after fertilization. The fertilized egg travels down the Fallopian tube into the uterus where it is embedded into the lining.
Maternal Changes -The ovaries increase the production of the "pregnancy maintaining" hormone, progesterone. Once the embryo is implanted, your normal menstrual cycle ceases. The first period is missed, usually the first signal to tell the new mum of the new life forming inside.
The walls of the uterus soften so that the embryo can become firmly embedded. The uterus enlarges almost from the moment of implantation. The normal cervical mucus becomes very thick forming a plug. This mucus plug should remain intact until just before labor starts.
Morning sickness may strike anytime from here in. It is thought that this is due to increased hormone activity, which slows the digestive system, to allow more absorption of nutrients for the baby. Most women find that morning sickness eases after the first trimester.
6th week
Baby’s Development - The embryonic cell layers have been formed – the ectoderm, endoderm, and mesoderm. These layers will generate every organ and tissue in your baby's body. The inner layer grows into the organs of breathing and digestion. The middle layer grows into cartilage, bones, connective tissues, muscles, the circulatory system, kidneys, and sex organs.
The outer layer grows into the baby's skin and nerves. By week 6 the first body segments will appear, these will eventually form the spine, brain and spinal cord. Limb buds develop and the embryo is about 0.5 cm long.
Maternal Changes - Your breasts may start to feel tender. The placenta grows to cover one-fifteenth of the uterine interior. This can be a time of great fatigue, often quite extreme in the first six weeks of the pregnancy, thought to be caused by a change in the ovarian hormones. Maybe it is nature’s way of making you slow down!
9th week
Baby’s Development - Major divisions of the brain can now be seen. The heart starts to pump blood. The eyes start to take shape and external ears develop from skin folds. The baby is now growing rapidly. The face is complete with eyes, nose, lips, and tongue. Small bones and muscles emerge under the skin. The internal and external parts of the ear begin to form and taste buds start to develop. The tooth buds of all the non-permanent teeth are now in place.
Maternal Changes - Your metabolic rate begins to increase requiring you to take in more calories and protein. The placenta starts to operate efficiently so that the exchange of nutrients and waste matter occurs. The two circulations are completely separate. The total blood volume begins to rise and about a quarter of this is being used by the placenta. Your breasts may start to swell. The tiredness often continues and you may even feel faint at times.
12th week
Baby’s Development – The baby is now about 7cm long (almost 3 inches), has facial features and can move, although you won’t be able to feel it just yet. The genitals are forming and the eyelids finish forming and seal shut. The fetus looks more like a human.
Maternal Changes - The placenta covers about one third of the uterus lining.
Maternal blood supply has increased by 30 – 40%.
Second Trimester
This is often the most enjoyable time of pregnancy. Morning sickness usually decreases, we experience the thrill of feeling our baby move for the first time and some even take on that “pregnancy glow”. Many of us see our baby’s heart beating for the first time through an ultrasound. Enjoy this time, pamper yourself, and learn a bit more about all the changes that are happening around and within you. You may also want to start thinking about the type of birth you are wanting. Get as much rest as possible but also try to keep up some regular exercise. Yoga is a great choice, as it will help you relax and is excellent birth preparation for your body.
16th week
Baby’s Development – The organs are now functioning and the lungs have developed and start to work. The baby’s movements have become much stronger and it is now about 16cm long (almost 6 1/2 inches). The genitals should be distinguishable. The musculoskeletal system has matured and the nervous system starts to have some control over the body.
Maternal Changes – The placenta has reached complete functional maturity and acts as your baby’s lungs, kidney’s, liver, digestive and immune system
Your pregnancy will now start to become more physically obvious. Your first ultrasound is usually scheduled about now.
20th week
Baby’s Development – All of the organs and structures have been formed and a period of simple growth begins. Bones are starting to develop. An oily coating protects the fetus.
Maternal Changes - You may now start to feel the fluttering movements, often called the “Quickening” if this is your first baby. If it is not your first, then you may have been feeling these movements for a couple of weeks now.
24th week
Baby’s development – The fetus now has a regular pattern of sucking, sleeping, turning, and kicking – and has probably found a favorite position in the uterus. The baby’s vital organs are developed well enough now that he would be able to survive outside the uterus. This is usually considered the point of viability (there is a chance of survival outside the uterus) but it would mean many complications and intensive care for many months. Hair, eyebrows, and eyelashes are developing. The bone-forming cells increase their activity causing rapid development of the skeleton.
Maternal Changes – The placenta now covers one half of the uterine lining. Your breasts may begin secreting colostrum in preparation for nursing. You will start to gain more weight now as the baby starts to fill out. Your uterus should be about 2.5cm (1 inch) above your navel.
The Third Trimester
Your beautiful belly starts to grow much faster now and you are starting to feel much more prepared for the arrival of your baby. This is a good time to get into those antenatal classes, think about your birth plan and start preparing your nest. Above all, take care of yourself. Rest and relax as much as possible, even if you feel great, because life is about to change significantly. Take advantage of the increase in energy during the sixth and seventh month to organize yourself.
28th week
Baby’s Development - The baby is now able to open and close its eyes. It is covered with a greasy protective covering called vernix. It is about 38 cm long (just over 15 inches) and weighs about 1 kg. The structures of the spine have been developing over the last few weeks. The baby is now able to swallow, breathe, and regulate its body temperature to a certain extent, but is still very reliant on its mother. Your baby can hear your voice now so talk and sing to it often. Encourage your partner to do the same.
Maternal Changes – The placenta becomes thicker rather than wider. You may start to experience vivid dreams. Braxton Hicks (mock contractions) may be felt occasionally from here on in. These irregular and relatively painless contractions are preparation for the main event! You may start to feel shortness of breath as the uterus presses up into the ribcage.
32nd week
Baby’s Development – Your baby should now be two thirds of its birth size and fat deposits are building up under the skin. The skin is changing to be more opaque, losing the transparency it has had previously. Hair and toenails are growing.
A substance called surfactant has formed in the lungs, which will allow them to function independently at birth. Your baby has a reasonable chance of survival if born during this period. The brain is growing rapidly at this time causing significant growth of the head. All five senses are working. Red blood cell reduction has been occurring in the bone marrow for the last couple of weeks.
Maternal Changes – There is a decrease in the volume of amniotic fluid to make room for the growing fetus. Your spine and joints are softer than usual so extra care is needed when moving things around. Try to get someone to help you with shopping bags, laundry baskets and so on, and always avoid any heavy lifting. You may experience swelling of the ankles, which can be soothed by putting your feet up once or twice a day for an hour. Sleeping on your left side can also help with this.
36th week to full term
Baby’s Development – Our baby is almost ready to make an appearance. The lungs and digestive tract are now fully matured. The baby’s movements start to become a little restricted as almost the entire uterus is occupied. The skin becomes less red and wrinkled. This is a period of rapid growth for the baby as it grows from about 46cm to 50cm approaching birth. Fat deposits start to fill out the baby’s body.
Maternal Changes – Make sure you are eating lots of good food as this is the time when you and baby are going to need lots of fuel. You may feel some backache as the ligaments in your pelvic area start to loosen and stretch to accommodate the baby. This is generally the time of pregnancy when most of the discomfort sets in. Tiredness may come back but it may be difficult to sleep. You may experience the need to urinate frequently again as the expanding uterus compresses against the bladder. Try to reduce your activity level, conserve energy and fill up the sleep bank if possible. Pamper yourself as much as possible - have a massage, go out to lunch, relax in a bath, and just spend time preparing your mind and body for the coming weeks. Your baby could come at any time from here on in so make sure that bag is packed and all systems are go!
40th week – Full term
Baby’s Development – The maternal antibodies against many diseases have been transferred providing protection for the baby in the first six months of its life. Most of the vernix disappears. The average birth weight is between 2.5 and 4kg (around 7.5 pounds) with a body length of between 47 and 53cms (around 20inches) long.
Maternal – The baby moves down into the pelvis in preparation for the birth and the head “engages”. Sometimes the baby doesn’t position itself ideally and has its feet first. This is called a breech birth. A breech baby is usually picked up before birth and the doctor or carer will advise accordingly.
Remember that the estimated due date is just that and babies usually do come when they are ready. You are not technically overdue for another week or so yet. If your doctor wants to think about induction make sure you are clear about your own wishes. There are some ways you can induce labor naturally if things are not moving by the 42nd week or if medical intervention is eminent.
You may have experienced irregular “false” contractions at intervals over the last few weeks. The on set of “true” regular contractions heralds the beginning of labor, which completes nine miraculous months. The placenta has been slowly deteriorating towards the end of pregnancy and will be expelled after the baby is born.
You’ve got the whole world in your hands.
This is how it feels when you hold your beautiful baby for the first time. We are all totally astounded by the miracle of new life – after nine months of nurturing it is so wonderful to finely meet the new life you have created. You are going to experience feelings you never knew you had and life will take on a whole new meaning.
Congratulations and best wishes as you embark on the journey of parenthood – one of life’s greatest gifts and challenges.
Disclaimer
The information presented here is for educational and entertainment purposes only. Statements and opinions expressed throughout this article should not be considered fact or medical advice. The material within this article is without any kind of guarantee, expressed or implied, and soulbirth.com is not responsible for any type of loss or damage caused by anyone's dependence on the information. ALWAYS consult your health care provider if you have any questions regarding your health/well-being and that of your family.
References
Bryan, J (1994) The Miracle of Birth
Wishing Well Books, Australia
Nilsson, L (1990) A Child is Born
Doubleday Books, London
Stoppard, Dr M (1999) Conception, Pregnancy, and Birth
Viking Books, Australia.