5 Weeks Pregnant: What to Expect This Week
Week five is when many people first discover they are pregnant — and the embryo, though only the size of a sesame seed, is already making its presence known through a surge of hormones.
Baby at Week 5: Size of a sesame seed
Baby's Development at 5 Weeks
The most exciting development this week: the heart has started beating. It's a simple tube at this stage, but it's already contracting and circulating blood. The brain, spinal cord, and other major organs are beginning to take shape from three distinct layers of cells. Tiny arm and leg buds are emerging, and the basic structure of eyes, ears, and nose are forming. The placenta is growing rapidly to keep pace with the embryo's needs.
Your Body at 5 Weeks Pregnant
Fatigue hits hard for many people around week five — your body is producing enormous amounts of progesterone, which has a sedative effect. Nausea may begin, sometimes all day rather than just in the morning. Breast tenderness, frequent urination, heightened sense of smell, and mood swings are all par for the course. Some people also notice food aversions to things they previously loved.
Tips for Week 5
- Rest as much as you can — first-trimester fatigue is real and your body needs it.
- Small, frequent meals can help keep nausea at bay before it fully kicks in.
- Ginger tea, ginger chews, and vitamin B6 have good evidence for reducing nausea.
- Avoid hot tubs and saunas — raising core body temperature is a risk in early pregnancy.
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Frequently Asked Questions
When does morning sickness start?
Morning sickness typically begins between weeks 5 and 6 and peaks around weeks 8–9. Despite the name, it can occur at any time of day. For most people it eases significantly by the end of the first trimester, around week 13.
Is it safe to exercise at 5 weeks pregnant?
For most people, yes. Walking, swimming, yoga, and low-impact cardio are all considered safe in the first trimester. Avoid contact sports and activities with a high fall risk. Always check with your provider if you're unsure.
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