18 weeks + 2 days

Vernix (a white cheese-like protective material) forms on baby's skin with the lanugo (soft, lightly pigmented hair covering the body and limbs); both serving to protect your baby's skin during the months in water.
Your placenta continues to grow and nourish the baby.
Tiny air sacs called alveoli begin to form in lungs. He'll be putting these lungs to good use in just a few months!
Her vocal chords are formed. She goes through the motions of crying but without air she doesn't make a sound.
Features of your baby's heart, including ventricles and chambers, should be visible during an ultrasound.
Your baby measures about 5.59 inches this week and weighs about 6.7 ounces.