Baby is the size of a large pineapple
👶 Baby's development
Skull bones are still soft and flexible — to pass through the birth canal. Lungs are almost ready.
💛 How mom feels
Lower back pain intensifies. Colostrum may leak — this is normal. Learn labour breathing techniques.
📖 Tip of the week
The skull bones are still soft and movable — nature designed them this way for passing through the birth canal. The baby's immune system receives antibodies through the placenta. Practice breathing techniques for labor — they really help.
🔬 Detailed baby development
- The fetus's immune system is receiving antibodies from the mother through the placenta
- The pupils can detect light and adjust size accordingly
- The skull bones remain unfused, allowing flexibility for passage through the birth canal
- The fetus's coordination improves — it can grab its feet and suck its thumb with precision
- The nervous system and brain continue rapid development
- The fetus is about 43.7 cm long and weighs approximately 1,900 grams, roughly the size of a pineapple
🤱 What mom may feel
- Pelvic pressure increases as the baby grows heavier
- Waddling gait develops as hip joints loosen and the belly grows
- Occasional sharp pain in the ribs from the baby kicking upward
- Increased hunger and thirst as the baby puts on weight rapidly
- Hot flashes or night sweats due to increased metabolism
🏥 Tests and check-ups
Biweekly prenatal visit with standard monitoring. Provider will check fetal position and may discuss a plan if the baby is still breech. Blood pressure monitoring remains important for preeclampsia screening. If you have Rh-negative blood, the effect of the RhoGAM injection continues to provide protection.
💡 Tips for this week
- Take a warm shower before bed to help with sleep and relaxation
- Choose supportive shoes with good cushioning for your changing gait
- Continue eating small, frequent meals to manage heartburn and maintain energy
- Prepare important phone numbers: healthcare provider, hospital, labor support person, emergency contacts
❓ Frequently asked questions
Why do my ribs hurt?
As the uterus expands upward, the baby's feet can press against or kick the lower ribs. This is uncomfortable but harmless. Changing positions, stretching, or gently pushing the feet away can help. The pressure often eases when the baby drops lower.
What if the baby is breech at 33 weeks?
About 25% of babies are still breech at 33 weeks. Many will turn on their own by 36 weeks. Techniques like optimal fetal positioning (hands and knees exercises) may encourage turning. If the baby remains breech, an external cephalic version (ECV) may be offered around 36-37 weeks.
Is waddling normal?
Yes, the waddling gait is caused by your pelvis widening, shifted center of gravity, and relaxed pelvic ligaments. It is a natural adaptation to carry the extra weight. Pelvic floor exercises and a support belt can help with comfort.
📝 Week 33 of pregnancy: preparing for birth
At 33 weeks, your baby weighs approximately 2 kg and measures around 43 cm — the size of a pineapple. The skull bones are still relatively soft and slightly separated to allow the head to mould during birth — a remarkable adaptation that makes passage through the birth canal possible. Your baby’s immune system is receiving a significant boost as maternal antibodies cross the placenta in increasing quantities. Brain development at this stage is extraordinarily rapid, and your baby is now capable of coordinating complex movements such as sucking and swallowing simultaneously.
You may find that physical discomfort increases noticeably at this stage as there is simply less space in your abdomen. Rib pain is a common complaint, particularly if the baby is lying in a position that places pressure under your ribs — gentle stretching and positional changes can provide temporary relief. Sleep disturbance is almost universal at this stage, due to a combination of physical discomfort, frequent urination, and understandable anxiety about the birth. Many women find mindfulness techniques and hypnobirthing practices helpful for managing anxiety and promoting restful sleep during the third trimester.
Antenatal appointments continue every 2 to 4 weeks, with close monitoring of blood pressure, growth, and your overall wellbeing. Your midwife will discuss the signs of preterm labour with you — these include regular contractions before 37 weeks, lower back pain, pelvic pressure, and changes in vaginal discharge. If you notice any of these signs, contact your maternity unit immediately. The Group B Streptococcus (GBS) test is not routinely offered on the NHS but is available privately; discuss this with your midwife if you have concerns, as GBS can affect the baby during birth.
Nutrition at 33 weeks should continue to emphasise calcium (for bone development), iron (to prevent anaemia), and vitamin C (which enhances iron absorption). Consuming foods rich in vitamin K — such as green leafy vegetables — is also beneficial. If you are experiencing significant heartburn, your GP can prescribe safe antacids; over-the-counter preparations such as Gaviscon are also considered safe in pregnancy. Begin to research cord blood banking if this is something you wish to consider, as arrangements must be made before the birth.
⚠️ When to see a doctor
- Vaginal bleeding
- Sudden decrease in baby movements (fewer than 10 in 2 hours)
- Severe headache or seeing spots
- Swelling of face, hands, or sudden leg swelling
- Leaking or gushing of amniotic fluid
- Regular contractions before 37 weeks (every 10 minutes)
- Fever above 38°C (100.4°F)
Sources
- WHO recommendations on antenatal care (2016)
- ACOG Practice Bulletins
- Williams Obstetrics, 26th Edition
📝 Create Your Birth Plan
Free AI-powered birth plan generator. Answer a few questions — get a personalized PDF birth plan in 2 minutes.
Create Birth Plan →🤰 Pregnancy tracker
Enter your last period date — find out your week, count kicks, keep a diary
Open tracker →