7 weeks pregnant, or 5 weeks after conception: organ development

This week, your baby's nostrils become visible and their retinas start to form. Little buds, which will eventually become arms and legs, are growing. The heart morphology becomes more complex as the four chambers of the heart and their valves begin to form.

The most important development this week is the cortex, your child's brain is developing with the appearance of the two hemispheres and grey matter.