5 weeks pregnant: Pregnancy Symptoms & Baby Development

Baby development at 5 weeks

Your baby’s vital organs are developing fast, including their heart.

What does my baby look like? And, what size is my baby?

In week 5 of pregnancy, your baby, technically called an embryo, measures a little over 1mm long – that’s roughly the size of a sesame seed. But already their brain, spinal cord and blood vessels are beginning to develop, albeit on a microscopic scale. Their circulatory system is also developing and it’s at around the end of week 5 that your baby’s heart starts to beat.

Meanwhile, the umbilical cord, which will deliver nutrients to your baby, is beginning to form. The amniotic sac, soon to be filled with a clear, pale fluid to cushion your baby, starts to take shape too.

Pregnancy at 5 weeks (first trimester)

What’s happening in my body?

This may be the week that you find out for certain that you’re pregnant. If you’re not convinced by the absence of your period or other symptoms such as tender breasts and tiredness, at 5 weeks your hormone levels should be high enough to confirm the news on a home pregnancy test.

Early pregnancy symptoms at 5 weeks

Early pregnancy symptoms vary from person to person. At 5 weeks, you may experience any of the following signs of pregnancy, or no symptoms at all: