Quick answer: Week 29: What GBS is, testing process, positive result meaning, antibiotics during labour.
Week 29 — you’re in the third trimester, the final stretch. Your baby is gaining weight rapidly, your body is working harder than ever, and the finish line is in sight. It’s completely normal to feel a mix of excitement, anxiety, and ‘let’s just get this done.’
Baby Development This Week
At week 29, your baby is approximately the size of a butternut squash — measuring around 15.2 in / 38.6cm. Muscles and lungs are maturing fast. Baby is very active. Growth and final organ maturation are the priorities now. Your baby gains approximately half a pound per week from week 28 onward, laying down the fat deposits that will regulate body temperature after birth.
Symptoms You May Feel
Third trimester week 29 commonly brings: shortness of breath as the uterus presses against the diaphragm (improves when baby drops lower, usually weeks 36–38 for first pregnancies), heartburn at its peak as the stomach is compressed, frequent urination returning with a vengeance, swollen ankles and feet from fluid retention and venous compression, pelvic pressure and occasional ‘lightning crotch’ (sharp nerve pain), Braxton Hicks becoming more frequent and sometimes intense, carpal tunnel syndrome from fluid pressing on wrist nerves, and sleep disruption from physical discomfort and frequent waking.
What GBS is, testing process, positive result meaning, antibiotics during labour
Group B Streptococcus (GBS) is a bacterium that colonizes the vaginal and rectal area of approximately 25% of healthy women — it causes no symptoms and is harmless to adults. The concern in pregnancy is transmission to the newborn during vaginal birth, which can (rarely) cause serious neonatal infection. The CDC and ACOG recommend universal GBS screening at 36–37 weeks (not 29 weeks) — a vaginal and rectal swab that takes seconds and is processed in 24–48 hours. Week 29 is too early for the actual test, but it’s the right time to understand the process. A positive result does not mean you cannot have a vaginal birth — it means you will receive IV antibiotics (typically penicillin) during labor, which reduces neonatal GBS transmission by approximately 80%. Women who are GBS positive are not treated with antibiotics during pregnancy because the bacteria would simply recolonize before birth. If you have a planned C-section before labor begins and your membranes haven’t ruptured, intrapartum antibiotics for GBS are not required regardless of your carrier status. GBS status can change between pregnancies — a negative result in one pregnancy does not mean you’ll be negative in the next.
Practical Tips for Week 29
- Sleep on your left side — it optimizes blood flow to the placenta and reduces vena cava compression.
- Start kick counts from week 28 — 10 movements in 2 hours is the standard guideline; call your provider if concerned.
- Pack your hospital bag by week 35 — babies don’t always wait until their due date.
- Practice perineal massage from week 34 to reduce tearing risk at birth.
- Attend all antenatal appointments — monitoring frequency increases in the third trimester for good reason.
- Discuss your birth preferences with your provider before week 36.
When to Call Your Midwife or OB
In the third trimester, call your provider immediately for: fewer than 10 fetal movements in 2 hours, regular painful contractions before 37 weeks, severe persistent headache with visual changes or facial swelling (preeclampsia warning signs), any bleeding, signs of water breaking, or any gut feeling that something isn’t right. From week 29, always err on the side of calling — your team would always rather you check in unnecessarily than miss something important.
Frequently Asked Questions
How do I know if I’m in labour?
True labour contractions are regular, progressively stronger, longer, and closer together — and they don’t stop with rest, hydration, or position changes (unlike Braxton Hicks). They typically start every 10–15 minutes and intensify over hours. Other labour signs include: bloody show (pink-tinged mucus from the cervical plug), your water breaking, and lower back pain that radiates to the front. The 5-1-1 rule for hospital: contractions every 5 minutes, lasting 1 minute, for 1 hour.
Is extreme fatigue normal at week 29?
Absolutely. Third trimester fatigue combines extra physical weight, disrupted sleep, frequent urination, and the enormous metabolic cost of a baby gaining half a pound weekly. Your cardiac output is 30–50% above baseline, your kidneys filter 50% more blood, and your body produces extra blood, hormones, and nutrients continuously. Rest is not laziness at this stage — it is medically appropriate preparation.
What is the mucus plug and when does it come out?
The mucus plug is a thick collection of cervical mucus that seals the cervix throughout pregnancy to protect against infection. It can come out days or even weeks before labour, or during early labour itself. It may be clear, white, yellow, or tinged with pink or brown blood. Losing it doesn’t mean labour is imminent, but it does mean your cervix is beginning to prepare. Any bright red bleeding should always be reported to your provider.
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Related Reading
- 28 weeks pregnant: kick counts and why they matter
- Group B Strep in pregnancy: what a positive test means for birth
- 30 weeks pregnant: hospital bag — start packing now
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