Pregnancy Week 18: What to Expect
Baby's development, your body's changes, common symptoms, what to eat, and what to do this week.
Baby's development at week 18
Baby's nervous system matures rapidly. Myelin (a protective coating on nerve fibers) starts to form. Baby's hearing is well-developed; sudden loud noises can make baby move. Baby's kidneys produce urine. Baby's intestines start producing meconium — the dark green-black "first poop" that will be passed in the first day or two after birth (or sometimes in utero if there is stress). Baby's external genitalia are clearly defined.
What's happening in your body
Your uterus is rising fast. Blood volume continues to climb. Cardiac output peaks around weeks 24-32. You may feel slightly out of breath with stairs or activity. Skin on the belly stretches — itching is common. Hair growth on the head is at peak fullness. Sleep can get harder — lying flat is uncomfortable, lying on your back is discouraged, lying on your side requires a pillow.
Common symptoms at week 18
Trouble sleeping (more body to maneuver, frequent peeing, baby movements). Linea nigra prominent. Possible mild leg cramps at night. Stuffy nose. Stronger kicks. Mild heartburn. Possible feet/ankle swelling at end of day. Possible mild dizziness from blood pressure shifts.
When to call your provider
Decreased fetal movement — once you have established a regular pattern (usually by week 22-24), any noticeable decrease warrants a call. Severe persistent headache or vision changes. Sudden swelling. Sharp abdominal pain.
How to feel better this week
Sleep on your left side when possible (better blood flow). Use a pregnancy pillow or two regular pillows — one between knees, one supporting the bump. Take breaks to put your feet up. Stay hydrated; counterintuitively, dehydration makes swelling worse. Talk to baby; baby recognizes your voice now. Practice Kegels. Continue daily walks.
Nutrition focus for week 18
Continue iron, calcium, vitamin D, protein, healthy fats. Add foods rich in choline (eggs, salmon, peanuts) for baby's continued brain development. Stay hydrated for swelling. Limit very salty foods if swelling is bothersome.
For your partner
Talk and read to the bump. Both your voice and your partner's voice. Newborns can recognize voices they heard in utero — there is decent evidence partners' voices are also recognized.
This week's to-do
Sleep with pillows for support. Keep talking to the bump.
Is this normal?
Many people start sleeping on their left side at this stage. The left side is best for blood flow to baby, but if you wake up on your back occasionally, do not panic — just roll over. Many people use a pregnancy pillow.
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