23 Weeks Pregnant: Blood Vessels in the Lungs Are Developing

Week 23 continues an important theme in your baby's development: preparing the lungs for that very first breath, still months away but already being carefully built. Meanwhile, your body continues adjusting to the demands of late second-trimester pregnancy.

What's Happening With Your Baby This Week

About the size of a large mango or small grapefruit, your baby's respiratory system takes center stage this week:

• Blood vessels are developing within the lungs, an essential step in preparing for breathing after birth.
• Your baby's skin is starting to appear less translucent, gradually becoming more opaque as fat continues accumulating underneath.
• Rapid eye movements may begin, even though the eyes remain closed for now.
• Hearing continues sharpening, and your baby may increasingly respond to familiar voices, music, or sudden noises.
• Weight gain accelerates noticeably this week compared to earlier stages of pregnancy.

What's Happening In Your Body

• You may notice more distinct kicks and jabs as your baby's movements become stronger and more purposeful.
• Braxton Hicks contractions may continue occurring occasionally and irregularly.
• Swelling in the feet and ankles can increase, especially after standing for long periods or in warm weather.
• Stretch marks may continue appearing or darkening as your bump grows.
• Restless legs or difficulty finding a comfortable sleep position can start becoming more noticeable.

Practical tip: A pregnancy pillow supporting your belly, back, and knees can significantly improve sleep comfort as your bump grows — many people find this especially helpful starting around now.

What You Should Do This Week

• Watch for early signs of gestational diabetes screening timing — this is typically scheduled between weeks 24 and 28.
• Stay well hydrated and move regularly to help manage swelling, especially if you sit or stand for long periods.
• Try different sleep positions and supports to find what's most comfortable for you.
• Continue prenatal vitamins and a balanced diet supporting your baby's accelerating growth.
• Talk to your baby or play music if you're interested — hearing is developing well enough that this can be a meaningful bonding activity.

Frequently Asked Questions

Can my baby really recognize my voice by this stage?
While full "recognition" develops more clearly later, research suggests babies can hear and begin responding to familiar voices and sounds from around this stage onward.

Is significant swelling normal at 23 weeks?
Mild swelling, especially by day's end, is common. Sudden, severe, or one-sided swelling — or swelling paired with headaches or vision changes — should be reported to your doctor promptly.

What is the gestational diabetes screening, and why does timing matter?
It's a routine test checking how your body processes sugar during pregnancy, typically done between weeks 24–28, since this is when gestational diabetes most commonly develops or becomes detectable.

Is it normal to feel uncomfortable finding a sleep position now?
Yes, this becomes increasingly common as your bump grows. Side-sleeping with supportive pillows is generally recommended and most comfortable for many people at this stage.

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Medical Disclaimer: This article is intended for general informational purposes only and does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified gynecologist or healthcare provider regarding your individual pregnancy, symptoms, or concerns.