What is Group B Strep and when will I be tested?

Group B Streptococcus (GBS) is a common bacteria that many women carry harmlessly in the vagina or rectum. It can be passed to the baby during birth. You will be tested for GBS between weeks 35-37 with a simple swab. If positive, you will receive antibiotics during labor to protect your baby.

Is it normal for the baby to move less at 33 weeks?

Your baby may have less room to move as they grow, so movements may feel different — more rolls and stretches than sharp kicks. However, you should still feel regular movement. If you notice a significant decrease in movement, contact your healthcare provider immediately.

Third Trimester 33 weeks pregnant

Pregnancy Week 33 - Baby's Immune System Strengthening

At 33 weeks, your baby is about the size of a pineapple. Your baby's immune system is strengthening as antibodies pass from you through the placenta, providing protection against infections after birth. The bones are hardening, except for the skull, which remains flexible for birth.

Pineapple

Baby Size

43.7 cm (head to heel)

Length

1.9 kg

Weight

Week 33

of 42

Baby Development This Week

Your baby is receiving your antibodies through the placenta, which will provide immune protection during the first months of life. The bones in the body are hardening, though the skull bones remain separate and flexible to allow the head to mold through the birth canal. Your baby's skin is becoming pinker and less wrinkled as fat continues to accumulate. The brain is continuing to develop, and your baby may be experiencing rapid eye movements during sleep. The lungs are nearly mature, though they still need more surfactant.

Changes in Your Body

You may be feeling very pregnant at this point. The top of your uterus is about 5 inches above your belly button, and you may have gained 22-28 pounds. Some women experience increasing pelvic pressure as the baby grows and moves lower. You might notice more frequent Braxton Hicks contractions. Difficulty sleeping, heartburn, and shortness of breath are common. You may be visiting your healthcare provider every two weeks now.

Common Symptoms at Week 33

Pelvic pressureBraxton HicksHeartburnInsomniaShortness of breathSwelling

Tips for Week 33

Discuss Group B Strep testing with your provider (typically done at 35-37 weeks).
Prepare meals for the freezer for after the baby arrives.
Practice breathing techniques and labor positions.
Make sure your car seat is properly installed.

When to Call Your Doctor

Seek immediate care for signs of preeclampsia, preterm labor, heavy bleeding, severe headache, visual changes, or decreased fetal movement.

Frequently Asked Questions — Week 33

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