We are told that the concern about Strep B involves two groups at high risk of infection:
1. Premature infants under 37 weeks gestation
2. Any infant in utero with membranes released longer than 18 hours

Contractions are a possible indicator of infection, but this situation is a concern in weeks 0-36. After 36 weeks, Braxton Hicks are normal and a good sign of a healthy toned uterus getting ready to push a baby out.

A culture that shows Strep B in the vagina is not necessarily illness related. Just as we commonly have Strep A in our throats on a swab and have no sore throat symptoms (no strep throat), from one day to the next we can all culture positive for Strep B without any symptoms or danger to our unborn babies. This is why many practitioners refuse to test for it and simply wait to test until such time as the above two “at-risk infant scenarios” show up. One day a woman might test positive and the next be negative. To treat with antibiotics before labour would NOT be recommended. Why?
The woman’s body could build up a resistance to the antibiotics and so could her baby’s body. Then if either got a more serious infection after the birth, the antibiotics might be ineffective.

Taking antibiotics can also lead to thrush, vaginal yeast and severe colic in the months after birth. There is some indication that antibiotic use can lead to Vitamin K deficiencies in the baby.

I would advise pregnant women to do as many things as possible to minimize their risk of ANY infections and maximize their immune systems. Some safe suggestions:

1. Boost vitamin C in your diet—e.g., eat 2 grapefruit per day. Other good sources of Vitamin C are red peppers, oranges, kiwi fruit.

Boost Your Vitamin C

2. Drink a cup of echinacea tea or take 2 capsules of echinacea every day.

3. Get extra sleep before midnight. Slow down your schedule.

4. Take 1 tsp colloidal silver per day. Take it between meals. Hold the liquid in your mouth a few minutes before swallowing. Colloidal silver can be purchased in most health food stores. It is silver suspended in water. It is antibiotic in nature and safe in pregnancy if you limit the daily intake to 3 tsps or less. Do not take more because there is a danger of turning your skin permanently blue by overdosing.

5. Plan ahead for extra warmth after the birth for both the mother and baby. Hot water bottles, heating pads, hot packs, big towels dried in a hot dryer during the pushing phase all help keep the mamatoto extra toasty after birth and reduce stress. Have a friend or family member assigned to be in charge of the mother/baby warmth team. Colostrum is the best antibiotic treatment the baby could ever get.

6. Other good prevention tips: Keep vaginal exams to a minimum — 0 is best. Do not allow membrane stripping to start the birth (a.k.a. membrane sweeping). Do not permit artificial rupture of the membranes. Do not allow children of other families to visit the new baby for the first three weeks. Keep the older kids healthy so they are not sneezing and coughing on the new baby.

I often think we must have had a lot of women who were Strep B positive in the 1000 plus births I have attended. We do not test unless we have long rupture of membranes and/or a preemie. Once the baby is born, we keep all women warm and baby skin-to-skin with the cord intact and, of course, all our mothers breastfeed. I have never had a baby sick with Strep B in thirty years. Unfortunately, the use of high dose antibiotics on so many pregnant women has resulted in an increase in infant deaths due to E Coli. *

Prevent the diagnosis of positive for GBS: If your care provider wants you to go for GBS testing at 36 weeks gestation to comply with protocols, read this article by a Certified Nurse Midwife about the use of garlic in the vagina to knock out bacteria. Do this regimen prior to testing.
https://pubmed.ncbi.nlm.nih.gov/15651446/

Scroll down to the end of these references for newer info from Cochrane Database and other sources.

*References:
(1.) E. M. Levine et al., “Intrapartum Antibiotic Prophylaxis Increases the Incidence of Gram Negative Neonatal Sepsis,” Infectious Disease Obstetric Gynecology 7, no. 4 (1999): 210-213.
(2.) C. V. Towers and G. G. Briggs, “Antepartum Use of Antibiotics and Early-Onset Neonatal Sepsis: The Next Four Years,” American Journal of Obstetric Gynecology 187, no. 2 (2002): 495-500.
(3.) C. V. Towers et al., “Potential Consequences of Widespread Antepartal Use of Ampicillin,” American Journal of Obstetric Gynecology 179, no. 4 (1998): 879-883.
(4.) R. S. McDuffie Jr. et al., “Adverse Perinatal Outcome and Resistant Enterobacteriaceae after Antibiotic Usage for Premature Rupture of Membranes and Group B Streptococcus Carriage,” Obstetric Gynecology 82, no. 4, pt. 1 (1993): 487-489.
(5.) T. B. Hyde ct al., “Trends in Incidence and Antimicrobial Resistance of Early-Onset Sepsis: Population-Based Surveillance in San Francisco and Atlanta,” Pediatrics 110, no. 4 (2002): 690-695.
(6.) M. L. Bland et al., “Antibiotic Resistance Patterns of Group B Streptococci in Late Third Trimester Rectovaginal Cultures,” American Journal of Obstetric Gynecology 184. no, 6 (2001): 1125-1126.
(7.) M. Dabrowska-Szponar and J. Galinski. “Drug Resistance of Group 9 Streptococci,” Pol Merkuriusz Lek 10, no. 60(2001): 442-444.
(8.) R. K. Edwards et al., “Intrapartum Antibiotic Prophylaxis 2: Positive Predictive Value Antenatal Group B Streptococci Cultures and Antibiotic Susceptibility of Clinical Isolates,” Obstetric Gynecology 100, no. 3 (2002): 540-544.
(9.) S. D. Manning et al., “Correlates of Antibiotic-Resistant Group B Streptococcus Isolated from Pregnant Women,” Obstetric Gynecology 101, no. 1 (2003): 74-79
(10.)Cochrane Database: Jan. 2013 “Maternal colonization with group B streptococcus (GBS) during pregnancy increases the risk of neonatal infection by vertical transmission. Administration of intrapartum antibiotic prophylaxis (IAP) during labor has been associated with a reduction in early onset GBS disease (EOGBSD). However, treating all colonized women during labor exposes a large number of women and infants to possible adverse effects without benefit.”
http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD007467.pub3/abstract

UPDATE: Cochrane Library, June 10, 2014
Intrapartum antibiotics for known maternal Group B streptococcal colonization
Women, men and children of all ages can be colonized with Group B streptococcus (GBS) bacteria without having any symptoms. Group B streptococcus are particularly found in the gastrointestinal tract, vagina and urethra. This is the situation in both developed and developing countries. About one in 2000 newborn babies have GBS bacterial infections, usually evident as respiratory disease, general sepsis, or meningitis within the first week. The baby contracts the infection from the mother during labor. Giving the mother an antibiotic directly into a vein during labor causes bacterial counts to fall rapidly, which suggests possible benefits but pregnant women need to be screened. Many countries have guidelines on screening for GBS in pregnancy and treatment with antibiotics. Some risk factors for an affected baby are preterm and low birthweight; prolonged labor; prolonged rupture of the membranes (more than 12 hours); severe changes in fetal heart rate during the first stage of labor; and gestational diabetes. Very few of the women in labor who are GBS positive give birth to babies who are infected with GBS and antibiotics can have harmful effects such as severe maternal allergic reactions, increase in drug-resistant organisms and exposure of newborn infants to resistant bacteria, and postnatal maternal and neonatal yeast infections.

This review finds that giving antibiotics is not supported by conclusive evidence. The review identified four trials involving 852 GBS positive women. Three trials, which were more than 20 years old, compared ampicillin or penicillin to no treatment and found no clear differences in newborn deaths although the occurrence of early GBS infection in the newborn was reduced with antibiotics. The antibiotics ampicillin and penicillin were no different from each other in one trial with 352 GBS positive women. All cases of perinatal GBS infections are unlikely to be prevented even if an effective vaccine is developed.
Source: http://summaries.cochrane.org/CD007467/intrapartum-antibiotics-for-known-maternal-group-b-streptococcal-colonization

UPDATE April 2016: From the (30th Anniversary Special) copy of Midwifery Today Magazine. Quote: “Unlike the US, the UK does not recommend universal screening because, while GBS disease is the most common cause of infection in full-term newborns, it is statistically still quite rare.(Wickham discusses these numbers in depth.) The Royal College of Obstetricians and Gynecologists (RCOG) firmly states that it will not support routine screening for GBS “until it is clear that antenatal screening for GBS carriage does more good than harm and that the benefits are cost effective” –two factors that have yet to be affirmed in any research done to date.” End Quote

This was part of a book review in Midwifery Today Magazine, Spring 2016 for “Group B Strep Explained” by Sarah Wickham, Midwife, 2014, paperback, pub’d by AIMS