A beautiful milestone: the fetus can now hear sounds from the outside world. Your voice, music, and even loud noises can reach the baby through the amniotic fluid. The anatomy scan is typically scheduled around now, giving you a detailed look at your growing baby.
Your Baby This Week
Size: Sweet potato (about 14 cm, or 5.6 inches)
Weight: About 190 grams
- Hearing: The ears are now positioned on the sides of the head (having migrated from the neck), and the auditory system is functional enough to pick up sounds. Sudden loud noises may cause the fetus to startle.
- Nervous system: Myelin, a protective coating, is starting to form around nerves. This speeds up signal transmission.
- Yawning: The fetus yawns frequently, which may help regulate brain temperature and blood flow
- Genitals: Usually identifiable on ultrasound now
- Sleep cycles: The fetus starts to develop patterns of sleeping and waking, though they do not match yours
Your Body
- Feeling the baby move. By week 18, many people feel definite movements. These may still be subtle, like tapping or popping.
- Growing belly. Your uterus is approximately at the level of your navel.
- Lower blood pressure in mid-pregnancy is normal and may cause lightheadedness.
- Leg cramps, especially at night, may start occurring.
- Swelling in the feet and ankles, particularly at the end of the day.
What to Do This Week
- Prepare for the anatomy scan. This detailed ultrasound (usually between weeks 18 and 22) checks the baby's organs, spine, limbs, brain, heart, and placenta position. It typically takes 30 to 45 minutes.
- Decide if you want to know the sex. Tell the sonographer at the start of the appointment. If you want it to be a surprise, make sure they know.
- Stretch before bed to help prevent leg cramps. Staying hydrated and getting enough magnesium (from nuts, seeds, and dark chocolate) can also help.
Common Questions
What does the anatomy scan check?
The mid-pregnancy ultrasound (also called the structural or morphology scan) examines the baby's brain, face, spine, heart, stomach, kidneys, bladder, limbs, and placenta. It also checks amniotic fluid levels and can often determine the sex. If anything looks unusual, your provider will explain the next steps.
Can the baby hear music?
Yes. Research shows that fetuses respond to music by changing their heart rate or moving. Some studies suggest babies may recognize music they heard frequently in the womb after they are born. Playing music or talking to your baby is a lovely bonding activity.