# Day 255: The GBS result

> Thirty-six weeks and three days. The group B strep swab happens around now. Today the result goes on your card, with the words to say at check-in.

- Series: Your ninth month of pregnancy, day by day (https://chorevia.com/learn/pregnancy-month-9), day 255 of 280, 36 weeks + 3 days
- Your baby this week: about the size of a romaine lettuce; around 47.4 cm from head to heel
- Canonical URL: https://chorevia.com/learn/pregnancy-month-9/day-255
- Last reviewed: 2026-10-22
- Publisher: Chorevia (https://chorevia.com)
- Cite as: Chorevia. "Day 255: The GBS result." Last reviewed October 22, 2026. https://chorevia.com/learn/pregnancy-month-9/day-255

This guide is general education that summarizes published research and guidance from groups like the American Academy of Pediatrics, the CDC, and the WHO. It isn’t medical advice, and every child develops on their own timeline. Your pediatrician knows your child; if something feels wrong, call them. In an emergency, call 911.

Thirty-six weeks and three days. The group B strep test is usually done at 36 to 37 weeks ([OWH](https://womenshealth.gov/pregnancy/youre-pregnant-now-what/prenatal-care-and-tests)), so the result may already be in, or due this week. Today you make sure it travels with you.

## Your baby

Your baby is around 47.4cm from head to heel, about the size of a romaine lettuce ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/3rd-trimester/week-36/)).

Group B strep matters for the baby, not because it makes you ill. MedlinePlus says most babies exposed during birth do not become sick, but a few develop serious illness ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000511.htm)). The NHS adds that most infections in newborns are preventable ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/3rd-trimester/week-37/)). That prevention is what today's card is for.

## Your body

The test is a swab of the vagina and rectum, with no risks ([AAP](https://www.healthychildren.org/English/ages-stages/prenatal/Pages/Get-Tested-for-Group-B-Strep.aspx)). About 1 in 4 women carry group B strep ([OWH](https://womenshealth.gov/pregnancy/youre-pregnant-now-what/pregnancy-complications)), usually without symptoms or harm to themselves ([AAP](https://www.healthychildren.org/English/ages-stages/prenatal/Pages/Get-Tested-for-Group-B-Strep.aspx)). A positive result means the bacteria are present; it is not an infection or an STD ([AAP](https://www.healthychildren.org/English/ages-stages/prenatal/Pages/Get-Tested-for-Group-B-Strep.aspx)), and it isn't spread through sexual contact ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000511.htm)).

If yours is positive, your provider will give you antibiotics through an IV during labor ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000511.htm)). They work best given at least 4 hours before delivery ([AAP](https://www.healthychildren.org/English/ages-stages/prenatal/Pages/Get-Tested-for-Group-B-Strep.aspx)). And the Office on Women's Health says to tell the labor and delivery staff you carry it when you check in ([OWH](https://womenshealth.gov/pregnancy/youre-pregnant-now-what/pregnancy-complications)). Your chart should say so. Say it anyway.

## Try today

### The GBS result plan

- **Time:** 5 minutes

1. If you haven't had the swab yet, ask at your next weekly check when it's booked ([AAP](https://www.healthychildren.org/English/ages-stages/prenatal/Pages/Get-Tested-for-Group-B-Strep.aspx)).
2. When the result comes, write it on your reference card: "GBS negative" or "GBS positive."
3. If it's positive, add the line to say at check-in: "GBS positive, antibiotics please" ([OWH](https://womenshealth.gov/pregnancy/youre-pregnant-now-what/pregnancy-complications)).
4. Ask your provider one question and write the answer beside it: "With a positive result, when should I come in?"

**Make it work:** Put the same line in the note on your partner's phone. If you're busy with a contraction at the desk, they can say it.

## Watch for

- **Normal:** feeling warm most of the time. **Call your provider** right away for a fever of 100.4°F (38°C) or higher ([CDC](https://www.cdc.gov/hearher/maternal-warning-signs/index.html)); a fever in labor is also one of the things that raises the chance of passing GBS to the baby ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000511.htm)).
- **Normal:** more discharge late in pregnancy. **Call your provider** right away if you might be leaking amniotic fluid ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000508.htm)); going 18 or more hours after the waters break without delivery is another GBS risk factor ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000511.htm)).
- **Normal:** discharge that's clear or white. **Call your provider** if it has a foul odor, a greenish color, itching, or pain ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000583.htm)).

## For you

A positive result can feel like a mark against you. It isn't. It's common, it isn't sexually transmitted, and the plan for it is routine.

It also changes nothing about feeding: women who test positive can breastfeed ([AAP](https://www.healthychildren.org/English/ages-stages/prenatal/Pages/Get-Tested-for-Group-B-Strep.aspx)).

If you're the partner: learn the line on the card by heart. At check-in, you may be the one with free breath to say it.

## Sources

- Office on Women's Health. "Prenatal care and tests." U.S. Department of Health and Human Services. https://womenshealth.gov/pregnancy/youre-pregnant-now-what/prenatal-care-and-tests
- NHS. "Week 36." Week-by-week guide to pregnancy, Best Start in Life. https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/3rd-trimester/week-36/
- MedlinePlus. "Group B streptococcus - pregnancy." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000511.htm
- NHS. "Week 37." Week-by-week guide to pregnancy, Best Start in Life. https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/3rd-trimester/week-37/
- American Academy of Pediatrics. "Pregnant Moms: Get Tested for Group B Strep." HealthyChildren.org, 2019. https://www.healthychildren.org/English/ages-stages/prenatal/Pages/Get-Tested-for-Group-B-Strep.aspx
- Office on Women's Health. "Pregnancy complications." U.S. Department of Health and Human Services. https://womenshealth.gov/pregnancy/youre-pregnant-now-what/pregnancy-complications
- Centers for Disease Control and Prevention. "Urgent Maternal Warning Signs and Symptoms." HEAR HER campaign, 2024. https://www.cdc.gov/hearher/maternal-warning-signs/index.html
- MedlinePlus. "Am I in labor?" National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000508.htm
- MedlinePlus. "Common symptoms during pregnancy." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000583.htm