Louise How big is my baby at Week 5 of Pregnancy? If you are 5 weeks pregnant, you might be curious about the size of your growing baby.
At 5 weeks pregnant, you might not even know you’re expecting yet—but your baby is already hard at work developing.
Your baby is now around 5mm long, about the size of a grain of rice. While still resembling more of a tadpole than a tiny human (yes, there’s even a little tail!), major developments are happening fast.
What’s Happening Inside at 5 Weeks Pregnant?
This is often the week people start to feel pregnant. Hormones like oestrogen, progesterone, and hCG are working hard—and your body is responding.
At this stage:
Sore or swollen breasts
Mild cramping (similar to period pains)
Exhaustion
Mood swings
Morning sickness (that can strike any time of day!)
Heightened sense of smell or food aversions
📝 Tip: Keep a symptom journal—it’s helpful for your own awareness and to share with your midwife later.
Folic Acid (or Folate): Are You Taking It?
You should now be taking 400 micrograms (0.4mg) of folic acid daily to support the development of your baby’s brain and spinal cord. This helps prevent neural tube defects such as spina bifida, and is recommended until at least week 12.
If you prefer, you can take folate instead—a natural form of vitamin B9 found in food and some supplements. Some people find it easier to absorb, especially if they have an MTHFR gene variation, but either folic acid or folate will help support your baby’s development.
Not sure which to opt for – check out our blog on Folate vs Folic Acid
Just found out you’re pregnant? Don’t worry—start now and keep going daily.
Time to Ditch Bad Habits
If you haven’t already:
Stop smoking – it increases the risk of miscarriage, premature birth, and low birth weight.
Avoid alcohol – especially during early development. Heavy drinking can cause Foetal Alcohol Spectrum Disorder (FASD).
For extra help with quitting, you can access free support through the NHS Smokefree programme including advice, tools, and one-to-one support.
Can I Exercise at 5 Weeks Pregnant?
Yes—you can continue most forms of safe exercise. Just avoid high-impact or risky sports where you could get knocked about (bungee jumping is a no!).
Your baby is well cushioned in your womb right now—like a grain of rice in a peanut butter sandwich—but check with your healthcare provider if you’re unsure about your specific activity.
Should I Tell People I’m Pregnant Yet?
This is a personal choice. Some people wait until after the 12-week scan; others tell close friends and family sooner. There’s no right or wrong—do what feels right for you.
Quick Recap: What to Do This Week
✅ Keep taking folic acid / folate
✅ Contact your GP if you haven’t already
✅ Note any symptoms
✅ Avoid smoking and alcohol
✅ Rest when you need to
✅ Be kind to yourself—you’re growing a whole human!
FAQs – 5 Weeks Pregnant
Can I feel pregnancy symptoms at 5 weeks?
Yes! Many people notice nausea, sore breasts, or tiredness around this time—but it’s also okay if you don’t.
Is the baby’s heart beating at 5 weeks?
Yes—by the end of week 5, the heart often begins beating, although it’s not detectable yet on a scan.
What should I avoid at 5 weeks pregnant?
Avoid smoking, alcohol, and any unsafe physical activities. Speak to your GP about any medications you’re taking.
