First Trimester

The first trimester of pregnancy covers between weeks 1-13, or the first three calendar months. For at least half of this time, you may not even be aware that you are pregnant. The first week of pregnancy is included in the first trimester, in the time when you may be having your period, confusing as it sounds. This is because it is seen as a time marker for when ovulation is most likely to have occurred. For the majority of women this is somewhere around 14 days from the first day of her last period, though the time varies depending on the length of each woman’s individual cycle.

Some pregnancy experts talk of gestational age and how this compares with foetal age. Gestational age is the age of the pregnancy and weeks since the last period, while foetal age refers to the actual age of the maturing baby. Throughout this series and commencing with the first trimester, we will talk about gestational age because most of the information around pregnancy does this as well.

How you may feel

By the end of the first trimester most women have had their pregnancy confirmed. If you haven’t made an appointment to see a midwife or doctor, make sure you tick it off on your to do checklist. Some of the earliest signs of pregnancy have already been discussed (Check week 6) but here are some others:

  • Breast changes including tenderness, tingling, increased sensitivity and a darkening of the areola (the skin around your nipple).
  • Needing to wee more frequently than normal. This is because of the increased blood volume as well as your uterus placing pressure on your bladder.
  • Feeling tired, not having any energy and wanting to sleep a lot. You may feel dizzy or light-headed because of the changes in your blood sugar levels.
  • Feeling nauseated, having morning sickness, which might not just be limited to the early part of the day.
  • Being moody and easily irritated. You may be a bit teary and not as even tempered as you usually are.
  • It is very normal to feel anxious about the possibility of miscarriage. This most commonly occurs in the early weeks which is why, for most women by the time they progress to the end of their first trimester; they feel they can relax a bit.

How you may look

  • At twelve weeks your uterus will be starting to lift out of your pelvis and a small bump may be visible in your lower tummy. This won’t be obvious to others, though you may start to show earlier if you have had a baby before.
  • Your breasts may increase a lot in the first trimester and look bigger than they normally do. Be prepared to buy new bras in a larger size.

Now we will start to look at each of the 13 weeks in the first trimester in more detail and what you can expect.



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