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First trimester

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First Trimester – What to Expect

Pregnancy is generally split into three trimesters of around 14 weeks each.  The first trimester starts from the first day of your last period, and will end around the time of your first ultrasound scan.  This is crucial stage in the development of your baby, as she changes from a single cell into a tiny baby about 8cm long, with all her main features recognisable.  And all in just over 3 months! 

Your Baby’s Development

The countdown to arrival of your baby starts before you even conceive.  Ovulation dates vary, so doctors and midwives use the menstrual cycle as their guide for predicting when you conceived, and when your baby is due.

Typically, ovulation will occur after about two weeks.  As soon as it is fertilised your body springs into action, releasing hormones that trigger changes in your body to accommodate your new baby.  Sometime between the third and fourth week, the fertilised egg will arrive in the uterus, where it becomes embedded in the lining and becomes known as an embryo.  This is the point beyond which you can accurately take a home pregnancy test and discover the exciting news!

Over the next few weeks your baby develops rapidly.  The brain, spinal cord and nerves and backbone are among the first to develop.  All the major organs such as the kidneys, liver and intestines begin to grow, and the embryo sprouts little buds that will become the arms and legs.

Sometime between 11 and 14 weeks you will have an ultrasound scan.  During this non-invasive procedure various measurements will be taken to ascertain a more accurate due date, and risk factors for conditions such as Down’s Syndrome.  It will also check that all the main body parts of your baby are developing as they should be.  Further tests may be required depending on the results.


first trimester

How Your Body is Changing – What’s Normal

With such a lot going on it’s no surprise that your body changes dramatically during this first stage of your pregnancy and hormones are largely responsible for many of the following symptoms you may be experiencing:

  • Fatigue – your body is exceedingly busy, and this can be very tiring
  • Morning sickness – this is a misnomer  – it can in fact last all day, and although not pleasant it is normal for some women.
  • Frequent urination – caused by hormones and pressure on your bladder
  • Heartburn – hormones slow down your digestive system, which means food stays in your stomach longer and can cause heartburn
  • Constipation – slower digestion can cause constipation, bloating and gas
  • Mood swings – grumpy or euphoric, and anything in between
  • Growing waistline – to accommodate your expanding uterus
  • Visible veins – these are in response to your body making extra blood for the baby, and pumping it faster to compensate for the extra needs

All women are different, so if you don’t experience any of these symptoms that’s quite okay.  Your blood will be tested during the first trimester to check for type, and to ascertain if you have any treatable health problems that may affect your baby, such as low iron levels, or a propensity for gestational diabetes.

If your blood type is Rhesus Negative (Rh), you will be checked for the presence of  R antibodies – in certain circumstances these antibodies can attack the placenta and harm the baby.  If found to be at risk treatment is a simple injection to counter the problem.

Most women have a monthly check-up that may repeat blood tests if necessary, and urine tests are sometimes also requested to check for the presence of proteins, which can lead to complications.

When to be Concerned

Growing a baby is a complex job for your body, and sometimes things can go wrong.  This is perhaps the most critical period of your pregnancy, so if you experience any of the following symptoms then it is advisable to talk to your doctor or midwife a soon as possible:

  • Bleeding – spotting can occur after 1-2 weeks when the embryo implants in the uterus, but any other bleeding is not normal and should be checked out
  • Abdominal Pain – aches and pains throughout the body are a part of pregnancy, but any persistent pain in your abdomen needs attention
  • Excessive nausea and vomiting – can cause dehydration and electrolyte imbalance
  • High Fever – could be a sign of infection
  • Vaginal discharge or discomfort – may be a sign of infection
  • Pain during urination – urinary tract infections can cause complications, so get this looked at
  • Leg Pain or Swelling, or Severe Headaches – relatively uncommon, these pregnancy side effects can indicate high blood pressure or presence of dangerous blood clots in your system






About Cally Worden

About Cally Worden

Seasoned freelance writer Cally Worden lives with her family and dog in a quiet corner of rural France. A love of the outdoors, and a fascination with her children's ability to view life with fresh eyes provide the inspiration for much of her work. Cally writes regularly for various websites and UK print publications on subjects as diverse as parenting, travel, lifestyle, and business, and anything that makes her smile.

Website: Cally Worden

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