Posted on
02 March 2010, under
Dad-To-Be; More Dad-To-Be articles...
We have a date!
It 'ALL' starts when one of your sperm burrows into her egg. It will hopefully end with the birth of your progeny. The nine month journey between these moments is an incredibly complicated process, and over the course of three articles we are going to try and simplify it a little - there are three articles as pregnancy is divided into three trimesters, each lasting about three months. Pregnancy lasts 40 weeks, and weeks 1-12 covers the first trimester.
This 40 weeks is timed as starting on the first day of her last period, so when she misses her period two weeks after conception then she is counted as actually being four weeks pregnant. If you want to get an estimate of when baby is due, take the date of her last period, add seven days and subtract three months (this presumes that her cycle is about 28 days long).
Conception normally takes place near the ovary, and the embryo then travels down the fallopian tube into the womb. About one week after fertilisation, the embryo (now a ball of about one hundred cells) attaches itself to the wall of the womb and literally burrows into it to establish a blood supply. This point of attachment to the womb develops into an organ called the placenta, which is where the mother’s blood supply interacts with the baby’s blood. The umbilical cord will eventually run from the placenta and attach to the baby at what will become the bellybutton. The embryo now sends hormonal messages to the mother’s body to prevent her from having a period, and she misses her period two weeks after conception (but four weeks into the pregnancy). These same hormones cause a pregnancy test to be positive.
Occasionally there is a light bleed around this time. Other than missing her period, the other most common symptoms which the mother might experience are tender breasts or some tiredness.
Multiple births occur when more than one egg is fertilised at the same time (non-identical twins), or when the fertilised egg divides after fertilisation (identical twins). Twin pregnancies occur in just under 1% of natural pregnancies, with triplets in about 1/10,000 pregnancies, but these rates are higher when pregnancies are assisted e.g. by using IVF.
The developing baby is called an embryo until the end of week 8, when it graduates to being called a foetus. At this stage it is about the size and shape of a cashew nut, and all of the major organs are taking shape. Morning sickness commonly starts around this time, and unfortunately is not limited to morning time. This is covered by a previous article here.
The baby’s organs all develop with remarkable speed through the rest of the first trimester. By the end of week 12, the foetus measures about 6.5 cm and is capable of simple movements such as curling its toes. The face is becoming developed and more clearly defined. At this stage the top of the mother’s womb can just be felt over the top of her pelvis.
Unfortunately, a considerable percentage of pregnancies do not make it through the first trimester. If your baby makes it through fertilisation, implantation and the development of the first trimester then the good news is that the risk of miscarriage becomes quite low.
Dr. Sean Hogan is a General Practitioner working in Waterford city. He went to college in UCC, and trained initially in Cork in a variety of medical speciallities. He then moved to Waterford, where he worked initially in hospital medicine before completing specialist General Practitioner training. His clinical interests include prevention of heart disease and diabetes, men's health and dermatology.
He feels strongly about the use of appropriate everyday language to explain medical terminology properly to patients, as he feels that this allows them to become more involved in their own healthcare. His other main qualifications for writing on fatherhood are Darragh (approaching his third birthday) and Ewan (aged six months).
Read 'Fearing Trimesters' by Jon Smith - Author of 'The Blokes Guide to Pregnancy' here...
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