Week 23
Your baby is the size of a grapefruit
What's happening this week
Your baby is the size of a grapefruit — about 11.5 inches from head to toe and weighing just over a pound. This week brings developments that are critical for your baby's ability to breathe independently after birth.
The lungs are beginning to produce surfactant — a complex mixture of lipids and proteins that coats the inside of the air sacs (alveoli) and prevents them from collapsing when your baby exhales. Surfactant production is one of the most important milestones in lung development, and its absence is the primary cause of respiratory distress in premature babies. At 23 weeks, the lungs are making small amounts; they won't produce enough for independent breathing until much closer to term, but this early production is a crucial start.
Your baby is also practicing breathing movements — rhythmically moving the diaphragm and chest muscles to 'inhale' and 'exhale' amniotic fluid. These practice breaths don't exchange gas (the placenta handles oxygen), but they strengthen the muscles your baby will need for that first real breath after birth.
Ridges are forming on the palms of the hands and soles of the feet — the foundations of fingerprints and footprints. Like the fingerprints that formed weeks ago on the fingertips, these patterns are completely unique.
Your baby now spends most of their sleep time in rapid eye movement (REM) sleep — the stage associated with dreaming in adults. What a 23-week baby 'dreams' about is a mystery, but the brain activity during REM sleep is thought to play an important role in neural development.
This week also marks the very edge of what medicine considers viability — with intensive neonatal care, some babies born at 23 weeks can survive, though the outcomes vary significantly. Every additional week in the womb dramatically improves the chances.
Your body this week
At 23 weeks, you're nearing the end of the sixth month of pregnancy. Your belly is growing steadily, and you may find that everyday tasks — tying your shoes, getting up from a low couch, reaching things on high shelves — are starting to require more creative maneuvering.
You might experience a phenomenon called 'pregnancy brain' — forgetfulness, difficulty concentrating, or feeling mentally foggy. Research on this topic is mixed, but many pregnant people report it as very real. It's likely caused by a combination of sleep disruption, hormonal changes, and the sheer cognitive load of preparing for a major life change. Be kind to yourself about it.
Linea nigra — the dark line running down the center of your belly — may be becoming more pronounced. It's caused by increased melanin production and will fade after delivery. Some people also notice their skin is more sensitive or itchy, especially over the abdomen where it's stretching most.
Your provider may start discussing the glucose screening test, typically done between weeks 24 and 28. This simple test checks for gestational diabetes by measuring how your body processes sugar. You'll drink a sweet glucose solution and have blood drawn one hour later. No fasting is required for the initial screening.
Back pain continues to be a common companion as your center of gravity shifts and your ligaments loosen. A prenatal massage (from a therapist trained in pregnancy massage) can provide significant relief and is safe for most pregnancies.
For dads
Your baby has reached the edge of viability this week — a medical term that means with the most advanced neonatal intensive care, some babies born now could survive. This isn't meant to scare you; the vast majority of pregnancies continue normally to term. But it does put into perspective how far you've come and how real this is. Your baby is a person now, with fingerprints, a sleep cycle, and lungs that are learning how to breathe. If the thought of premature birth makes you anxious, channel that energy into something productive: make sure your hospital bag plan is at least loosely sketched out, know the fastest route to the hospital, and have your insurance card accessible.
Your partner may be dealing with 'pregnancy brain' — a foggy, forgetful feeling that can be frustrating, especially at work. Don't joke about it or dismiss it. It's likely a real neurological effect of pregnancy hormones and sleep disruption, and it's temporary. What helps: be the person who remembers the appointments, tracks the to-do list, and follows up on things she mentioned needing to do. Being a reliable second brain is one of the most practical forms of support you can offer right now.
Common concerns
What is pregnancy brain, and is it real?+
Many pregnant people report increased forgetfulness, difficulty concentrating, and mental fog — commonly called 'pregnancy brain.' Research results are mixed: some studies show measurable changes in memory and attention during pregnancy, while others don't. What's clear is that sleep disruption, hormonal shifts, stress, and the cognitive demands of preparing for parenthood all contribute to feeling mentally scattered. It's temporary and typically resolves after birth (though sleep deprivation with a newborn brings its own cognitive challenges).
What is the glucose screening test?+
The glucose challenge test (GCT) screens for gestational diabetes and is typically done between weeks 24 and 28. You'll drink a 50-gram glucose solution (very sweet — like flat soda) and have blood drawn one hour later. No fasting is required. If your blood sugar is above a certain threshold, you'll be asked to take a longer, three-hour glucose tolerance test (GTT) that does require fasting. Gestational diabetes is common and manageable — catching it early is the goal.
Is it too early to think about childcare?+
It's actually not too early, especially if you plan to use daycare. In many areas, quality daycare centers have waitlists of 6-12 months or more. If you're considering daycare, start touring facilities and getting on waitlists now. If you're planning to have a family member provide care or hire a nanny, begin those conversations early too. Having a childcare plan in place reduces stress significantly in the third trimester and postpartum period.
When should I be concerned about preterm labor signs?+
Contact your provider immediately if you experience regular contractions (more than 4-6 per hour), a change in vaginal discharge (especially if it's watery, bloody, or mucus-like), pelvic pressure or a feeling that the baby is pushing down, lower back pain that comes and goes, or abdominal cramps with or without diarrhea. Preterm labor caught early can sometimes be slowed or stopped with medical intervention. If in doubt, always call — your provider would rather hear from you unnecessarily than miss early signs.
Product picks for week 23
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Prenatal massage gift certificate
Back pain and body tension are common now — a massage from a pregnancy-trained therapist provides real relief and relaxation.
Hospital bag checklist
It's not too early to start planning — a comprehensive checklist ensures you don't forget essentials when the time comes.
Memory and focus supplement (pregnancy-safe)
Pregnancy brain is real — a provider-approved supplement with DHA and choline supports cognitive function during pregnancy.
A quick note: This content is for informational purposes only and is not a substitute for professional medical advice. Always talk to your healthcare provider about any questions or concerns. Learn how we create our content.
Content based on guidance from the American College of Obstetricians and Gynecologists (ACOG), the American Academy of Pediatrics (AAP), Mayo Clinic, and peer-reviewed medical literature. Learn more about how we create our content.