Weekly Guide to Pregnancy: Week 5

Week 5
Week 5 

Your Baby

What happens after the blastocyst implants?

The blastocyst, which is your developing baby, is now called an embryo. By week 5, the inner cell mass of the blastocyst has flattened to form the embryonic disc and the body stalk. During this week, the inner cell mass (now the embryonic disc) further differentiates into three basic germ layers - ectoderm, mesoderm, and endoderm. Each of these layers is responsible for the development of different parts of your baby's body.

The ectoderm (outer layer) will provide the entire nervous system and brain, the skin, hair, glands, eyes and ears. The mesoderm (middle layer) will form the supporting structures such as the bones and joints, muscles, and connective tissue, together with the heart and kidneys and the vascular, genital, and urinary systems. Finally, the endoderm (inner layer) is responsible for the gastrointestinal tract, including the liver, gall bladder and pancreas, and the lungs. This week the major developmental activity occurs in the nervous system and heart.

This week the beginnings of the brain and spinal cord are formed. This occurs when 2 ridges form the neural canal which continues to grow until (at the end of the week) the ridges meet and fuse, forming an open-ended tube in the region that will become the back of your baby's head.

How big is my baby?

At the start of week 5, your baby hasn't grown much larger - the embryo is only about 1.25mm (0.05 inches) long.

Your Pregnancy

Will I be able to tell I'm pregnant this week?

It is at this stage that you may become aware that you could be pregnant, particularly if your period hasn't arrived and your menstrual cycle is regular and usually appears every 28 days. If you are planning a baby and your period fails to begin, this could well be the case.

Will a home pregnancy test give a positive result yet?

Home pregnancy tests measure the level of pregnancy hormone (hCG) present in your urine. The majority of home pregnancy test will confirm a positive pregnancy this week, but there may also be a few cases where a hpt does not give a positive result. In these cases the hormone levels may still be too low to register, particularly if the test has been performed too early in the pregnancy. Look for a test that offers early detection.

If your period still doesn't arrive, the test can be repeated the following week. Alternatively you can visit your doctor and have a blood test to confirm the pregnancy.

Other symptoms of pregnancy may include the need to urinate more often, breast tenderness and tiredness.

What should I be doing this week?

Here are some tips for week 5:

  • If you haven't already, start taking folic acid
  • Visit your doctor to confirm your pregnancy and talk about it
  • Eat a healthy, balanced diet
  • Quit smoking
  • Reduce alcohol and caffeine consumption
  • Incorporate a moderate exercise plan into your day
  • Avoid taking medication, especially Aspirin and Codeine. You should also obtain advice from your health care professional about the safe use of pain relievers such as Paracetamol
  • Avoid exposure to environmental poisons, pollutants and pesticides.

Learn more about your pregnancy

Read more information on Pregnancy and Birth on Essential Baby.

Discuss Pregnancy in the Essential Baby Forums.

The First Trimester

4 weeks pregnant
5 weeks pregnant
6 weeks pregnant
7 weeks pregnant
8 weeks pregnant
9 weeks pregnant
10 weeks pregnant
11 weeks pregnant
12 weeks pregnant

The Second Trimester

13 weeks pregnant
14 weeks pregnant
15 weeks pregnant
16 weeks pregnant
17 weeks pregnant
18 weeks pregnant
19 weeks pregnant
20 weeks pregnant
21 weeks pregnant
22 weeks pregnant
23 weeks pregnant
24 weeks pregnant
25 weeks pregnant
26 weeks pregnant
27 weeks pregnant

The Third Trimester

28 weeks pregnant
29 weeks pregnant
30 weeks pregnant
31 weeks pregnant
32 weeks pregnant
33 weeks pregnant
34 weeks pregnant
35 weeks pregnant
36 weeks pregnant
37 weeks pregnant
38 weeks pregnant
39 weeks pregnant
40 weeks pregnant