Medical Conditions

Group B Strep in Pregnancy

Content reviewed against published ACOG, CDC, March of Dimes guidelines

Editorial policy

Last reviewed:

If your baby has been diagnosed with or you suspect group b strep in pregnancy, here is what the evidence says.

The short answer

Group B Streptococcus (GBS) is a common bacterium found in about 25% of healthy women. Being GBS-positive is not an infection or STI - it simply means the bacteria are present in your body. With standard intravenous antibiotics given during labor, the risk of transmitting GBS to your baby drops from about 1 in 200 to about 1 in 4,000, making outcomes excellent.

Key takeaways

  • Group B Streptococcus (GBS) is a common bacterium found in about 25% of healthy women. Being GBS-positive is not an infection or STI - it simply means the bacteria are present in your body. With standard intravenous antibiotics given during labor, the risk of transmitting GBS to your baby drops from about 1 in 200 to about 1 in 4,000, making outcomes excellent.
  • Usually normal when: You tested GBS-positive at 36-37 weeks - this is a common finding in healthy women
  • Call your doctor if: Your newborn develops fever, poor feeding, extreme sleepiness, difficulty breathing, or irritability in the first week of life
  • Varies by age — see the age-by-age breakdown below
“Fever itself is not an illness — rather, it is a sign or symptom that the body is fighting an infection. Fever stimulates certain defenses, such as the white blood cells, which attack and destroy invading bacteria.”
— Fever and Your Child, American Academy of Pediatrics (AAP)

Thousands of parents search for this exact thing. You are not alone.

By Age

What to expect by age

First trimester

GBS screening is not typically done in the first trimester because colonization status can change throughout pregnancy. If you had a previous baby affected by GBS disease, your provider should be aware early so they can plan prophylactic antibiotics during labor regardless of your screening result later.

Second trimester

GBS screening is not routinely performed in the second trimester either. However, if GBS is found incidentally in a urine culture at any point during pregnancy (GBS bacteriuria), you will automatically receive antibiotics during labor. GBS in urine indicates heavy colonization and does not need to be re-screened later.

Third trimester

Universal GBS screening is recommended between 36-37 weeks of pregnancy through a simple vaginal and rectal swab. Results are available within a few days. If you test positive, you will receive IV penicillin or an alternative antibiotic during labor, ideally at least 4 hours before delivery. This is the standard of care and is highly effective at preventing early-onset GBS disease in newborns.

Postpartum

If you received appropriate antibiotics during labor, your baby will be observed for the standard period after birth. If antibiotics were not given or given less than 4 hours before delivery, your baby may be monitored more closely for 24-48 hours for signs of infection such as fever, poor feeding, irritability, or breathing difficulties. Early-onset GBS disease in newborns is treatable with antibiotics.

What Should You Do?

When to take action

Probably normal when...
  • You tested GBS-positive at 36-37 weeks - this is a common finding in healthy women
  • You received antibiotics during labor and your baby shows no signs of infection after delivery
  • You tested GBS-negative and your provider confirms no prophylaxis is needed
  • You had GBS in a previous pregnancy but tested negative this time (colonization can vary between pregnancies)
Mention at your next visit when...
  • You tested GBS-positive and are unsure about your labor antibiotic plan, especially if you have a penicillin allergy
  • Your labor is progressing very quickly and you are concerned about receiving antibiotics in time
  • You had a previous baby with GBS disease or a previous positive GBS urine culture
Act now when...
  • Your newborn develops fever, poor feeding, extreme sleepiness, difficulty breathing, or irritability in the first week of life
  • Your water breaks before 37 weeks and you know you are GBS-positive or your status is unknown

Doctor Visit Checklist

Bring this checklist to your next pediatrician visit to discuss Group B Strep in Pregnancy.

Things to mention

  • You tested GBS-positive and are unsure about your labor antibiotic plan, especially if you have a penicillin allergy
  • Your labor is progressing very quickly and you are concerned about receiving antibiotics in time
  • You had a previous baby with GBS disease or a previous positive GBS urine culture

Observations to share

  • You tested GBS-positive and are unsure about your labor antibiotic plan, especially if you have a penicillin allergy
  • Your labor is progressing very quickly and you are concerned about receiving antibiotics in time
  • You had a previous baby with GBS disease or a previous positive GBS urine culture

Urgent signs to report immediately

  • Your newborn develops fever, poor feeding, extreme sleepiness, difficulty breathing, or irritability in the first week of life
  • Your water breaks before 37 weeks and you know you are GBS-positive or your status is unknown

My notes

From ismybabyalright.com — free, evidence-based baby health guides

Milestone

Month-by-Month Development

Detailed monthly development guides from birth through 24 months.

Guide

When to Call the Doctor

General guide on when to call the pediatrician, visit urgent care, or go to the ER.

Frequently asked questions

Is group b strep in pregnancy normal?
Group B Streptococcus (GBS) is a common bacterium found in about 25% of healthy women. Being GBS-positive is not an infection or STI - it simply means the bacteria are present in your body. With standard intravenous antibiotics given during labor, the risk of transmitting GBS to your baby drops from about 1 in 200 to about 1 in 4,000, making outcomes excellent.
When should I call the doctor about group b strep in pregnancy?
Your newborn develops fever, poor feeding, extreme sleepiness, difficulty breathing, or irritability in the first week of life Your water breaks before 37 weeks and you know you are GBS-positive or your status is unknown
When is group b strep in pregnancy normal?
You tested GBS-positive at 36-37 weeks - this is a common finding in healthy women You received antibiotics during labor and your baby shows no signs of infection after delivery You tested GBS-negative and your provider confirms no prophylaxis is needed
What causes group b strep in pregnancy?
Group B Streptococcus (GBS) is a common bacterium found in about 25% of healthy women. Being GBS-positive is not an infection or STI - it simply means the bacteria are present in your body. With standard intravenous antibiotics given during labor, the risk of transmitting GBS to your baby drops from about 1 in 200 to about 1 in 4,000, making outcomes excellent. Common explanations include: You tested GBS-positive at 36-37 weeks - this is a common finding in healthy women. You received antibiotics during labor and your baby shows no signs of infection after delivery.
What should I mention to my pediatrician about group b strep in pregnancy?
You should mention group b strep in pregnancy at your next visit if: You tested GBS-positive and are unsure about your labor antibiotic plan, especially if you have a penicillin allergy. Your labor is progressing very quickly and you are concerned about receiving antibiotics in time. You had a previous baby with GBS disease or a previous positive GBS urine culture.
Is group b strep in pregnancy normal at First trimester?
GBS screening is not typically done in the first trimester because colonization status can change throughout pregnancy. If you had a previous baby affected by GBS disease, your provider should be aware early so they can plan prophylactic antibiotics during labor regardless of your screening result later.
Is group b strep in pregnancy normal at Second trimester?
GBS screening is not routinely performed in the second trimester either. However, if GBS is found incidentally in a urine culture at any point during pregnancy (GBS bacteriuria), you will automatically receive antibiotics during labor. GBS in urine indicates heavy colonization and does not need to be re-screened later.
Should I go to the ER for group b strep in pregnancy?
Seek emergency care if your newborn develops fever, poor feeding, extreme sleepiness, difficulty breathing, or irritability in the first week of life, or if your water breaks before 37 weeks and you know you are GBS-positive or your status is unknown. When in doubt, call your pediatrician's after-hours line for guidance.
Does group b strep in pregnancy go away on its own?
In many cases, group b strep in pregnancy resolves on its own, especially when you tested GBS-positive at 36-37 weeks - this is a common finding in healthy women. By Postpartum, if you received appropriate antibiotics during labor, your baby will be observed for the standard period after birth. If antibiotics were not given or given less than 4 hours before delivery, your baby may be monitored more closely for 24-48 hours for signs of infection such as fever, poor feeding, irritability, or breathing difficulties. Early-onset GBS disease in newborns is treatable with antibiotics.
ACOGCDCMARCH OF DIMES

References

  1. [1]American College of Obstetricians and Gynecologists. Prevention of Group B Streptococcal Early-Onset Disease in Newborns. ACOG Committee Opinion No. 797, 2020. ACOG
  2. [2]Centers for Disease Control and Prevention. Group B Strep (GBS). CDC, 2023. CDC
  3. [3]March of Dimes. Group B strep infection. March of Dimes, 2023. March of Dimes

All content follows our editorial policy and is reviewed against published clinical guidelines.

2,705 evidence-based guides6 authoritative medical sources

Related Resources

Well-Baby Visit PrepPregnancy TrackerBaby Tracker

Bottom line

Most cases of group b strep in pregnancy are normal. Talk to your pediatrician if your newborn develops fever, poor feeding, extreme sleepiness, difficulty breathing, or irritability in the first week of life.

Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.

Share:FacebookX

Was this page helpful?

Related Medical Concerns

My Baby's Head Shape Looks Abnormal

Many babies develop temporary head shape irregularities that are completely normal. A cone-shaped head from vaginal delivery reshapes within days. Mild positional flattening (plagiocephaly) from sleeping on the back is very common and usually improves with repositioning and tummy time. However, head shape changes involving ridges, a persistently bulging fontanelle, or rapid head growth changes should be evaluated to rule out craniosynostosis.

Achondroplasia (Dwarfism) in Babies

Achondroplasia is the most common form of short-limbed dwarfism, affecting about 1 in 15,000 to 40,000 births. It is caused by a mutation in the FGFR3 gene and is usually apparent at birth with characteristic features including short limbs, a larger head, and a prominent forehead. Intelligence is normal. With monitoring for specific complications and supportive care, children with achondroplasia lead full, active, and independent lives.

Adenoid Hypertrophy and Breathing

Adenoids are lymphoid tissue located behind the nose that help fight infection in young children. When adenoids become enlarged (adenoid hypertrophy), they can block the nasal airway, causing chronic mouth breathing, snoring, nasal speech, and sleep-disordered breathing. Enlarged adenoids are most common between ages 2-7 and are a leading cause of obstructive sleep apnea in young children. Treatment ranges from watchful waiting and nasal steroids to surgical removal (adenoidectomy) if breathing or sleep is significantly affected.

Adrenoleukodystrophy (ALD) in Babies

X-linked adrenoleukodystrophy (X-ALD) is a genetic disorder affecting about 1 in 17,000 newborns, caused by mutations in the ABCD1 gene on the X chromosome. It primarily affects boys and impairs the breakdown of very long-chain fatty acids (VLCFAs), which accumulate and damage the myelin sheath in the brain and the adrenal glands. The most severe form, cerebral ALD, typically affects boys between ages 4-10 with rapid neurological decline. Newborn screening now enables early detection, and hematopoietic stem cell transplant or gene therapy performed before significant brain involvement can be life-saving.

How to Advocate for Your Child's Needs

You know your child better than anyone, and your observations matter. If you feel something is not right with your child's development or health, you have every right to ask questions, request evaluations, and seek second opinions. Advocating for your child is not being difficult - it is being a good parent.

Agenesis of the Corpus Callosum (ACC)

Agenesis of the corpus callosum (ACC) is a condition in which the corpus callosum — the bundle of nerve fibers connecting the left and right hemispheres of the brain — fails to develop partially or completely. It occurs in approximately 1 in 4,000 births and is one of the most common brain malformations. ACC can be detected on prenatal ultrasound or postnatal MRI. Outcomes vary enormously: some individuals with isolated ACC have normal intelligence and minimal difficulties, while others (especially when ACC occurs alongside other brain abnormalities or genetic syndromes) may have significant developmental delays. The variability means that prenatal counseling and postnatal monitoring are both essential.