Fetal Development: Week 16
16 weeks after conception (4 months)
(18 weeks after the last menstrual period)
The fetus is about the size of a medium avocado or 5 ½ inches (5.5 inches) long from crown to rump (head to butt). The fetus weighs between 6 and 7 ounces. The ears are developed and stand out from the head. Breathing movements can be seen as the fetus’ chest moves in and out. The hair and nails begin to grow.
An avocado is 2.8 inches to 7.9 inches.