Your fetus is about 5 ½ inches long from head to bottom. This measurement makes him about the size of a bell pepper or small artichoke. He weighs about 5-7 ounces, and he will soon be large enough for you to feel his tossing and turning. His arms and legs are growing and becoming more proportional to his body, and he can now meet his hands in front of his body, make fists, and reach his hand to his mouth for some honest-to-goodness thumb sucking.
These newfound realizations and longer limbs have baby flexing and moving more than ever before, though you likely still won't feel him, not yet. His nervous system continues to develop, and the protective covering of myelin is beginning to form around his nerves as he creates more complex connections. This myelin substance speeds messages from nerve cell to nerve cell. Some of these nerve cells are in the brain and destined to specialize in the five senses. His lungs and immune system are also starting to develop and mature. Both are essential components to ensuring his survival outside the womb.
Somewhere around this week, your caregiver may schedule a fetal anatomy ultrasound. This test helps them identify anomalies in the growing fetus that may warrant further investigation. For you, this means potentially finding out the gender of your little one. If you don't want to know the gender, it is best to inform the technician and your caregiver early and often to avoid a slip of information from happening. You may also want to avoid looking at the ultrasound, as a penis is often readily identifiable even by the layperson.
- American Pregnancy Association - Week 18
- Mayo Clinic - Week 18: Baby begins to hear