Pregnancy Week by Week: 1-12 First Trimester

Week 1-12 of your pregnancy is a vulnerable period for the fetus, a time when each organ starts its development.

The length of pregnancy is 40 weeks, which is calculated from the first day of your last period. This may be a bit confusing because your ovulation is not until two weeks later. In reality this means a full-term baby is 38 weeks old.

The measurement that will be used throughout this trimester is called Crown-Rump-Length – CRL. It measures your baby from head to buttocks.

It is important to remember that all measurements are approximate. Your baby might be a slow grower compared to the average and still be perfectly normal.

Pregnancy Week by Week: 13-28 Second Trimester

From now, and until the end of your pregnancy, it is time for your baby to grow and mature.

In the third to fifth month your baby will primarily grow in length, while in the last two months of your pregnancy your baby will primarily gain weight.

If you have an ultrasound scan, your doctor can measure your baby from head to heel (Crown-Heel Length, CHL), or more likely he will measure the diameter of your baby’s head (Biparietal Diameter, BPD). He will probably also measure the length of your baby’s thighbone and the size of her/his stomach. Your baby is getting so big now that these ultrasound measurements are easier and more realistic. They can be used to follow your baby’s growth as a sign of well-being.

It is important to remember that all measurements are approximate, your baby might be a slow grower compared to the average, and still be perfectly normal.

Pregnancy Week by Week: 28-40 Third Trimester

Your baby is now growing rapidly and preparing for life on the outside. You will feel your baby moving around every day.

At this point many women fear that their baby will get caught in the umbilical cord while taking exercise. But remember that the umbilical cord is coiled and covered in gel, making it slippery, bouncy and long. If your baby has the umbilical cord around its neck do not worry – she/he will not be suffocated.

If you are worried or sense that your baby is moving less frequently, you should contact the local healthcare professional for a check up.

Your baby is mostly involved in growing during the next few months, so this trimester is divided not into weeks but into groups of four weeks.