Week 13 - Beginning of 2nd Trimester

• Your baby is about the size of a peach and is growing rapidly. Crown to rump, your baby measures 2.6 to 3.1 inches (6.5 to 7.8cm) and weighs 0.5 to 0.7 ounces (14 to 20g).
• Your baby's legs are longer than her arms and her skin is red and transparent.
• Her eyelids are fused together and won't open for about four more months.
• Her arms are long enough to reach her mouth and she may begin to place her thumb in her mouth. Her sucking reflex, however, is not yet developed.
• The tissue that will become your baby's bones is being laid out, especially around her head and her arms and legs.
• Some ribs may be distinguished at this time.
• The nose and chin are more prominent now.
• Your baby will begin to practice breathing in the next few weeks as her chest rises and falls in mock breathing motions.
• She will swallow small amounts of amniotic fluid which will be passed as urine.
• Your placenta is providing all of your baby's needs for nutrition, oxygen and waste disposal, though the amniotic fluid will become more important later on.
• All major components of the body are formed and now must grow and mature.
• From now on, your baby's development will consist primarily of organ maturity and growth and body refinement.