Little known to pregnant women, streptococcal B infections can have serious consequences on the health of the baby when they occur during pregnancy. Hence the importance of the screening recommended during the 8th month in order to be able to set up, if necessary, an appropriate antibiotic treatment during childbirth.

Group B streptococcus (Streptococcus agalactiae) is a common bacteria found in the digestive tract and urogenital tract. However, strep B infections are not considered sexually transmitted infections. The presence of this germ in the body is frequent and most often completely asymptomatic.

Between 5% and 40% of pregnant women are carriers of streptococcus B. Transmission of the bacteria from mother to child occurs in about half of the cases. It is most often done by inhaling or ingesting vaginal secretions during childbirth. But it can also occur during pregnancy, after inhalation or ingestion of contaminated amniotic fluid after premature rupture of membranes.

In case of contamination, the newborn can develop a severe infection (pneumonia, sepsis, meningitis). In France, each year, 500 cases of invasive neonatal infections associated with streptococcus B are counted. They cause between 50 and 100 deaths.

A newborn baby infected with streptococcus B will most often have a fever, difficulty breastfeeding and breathing, a bluish complexion, he will be irritable or lethargic. In the event of a diagnosis confirmed by blood test, treatment is primarily based on intravenous administration of amoxicillin over a period of 10 days to 3 weeks, possibly combined with another antibiotic for the first 48 hours.

At present, there is no vaccine capable of preventing streptococcal B infection. As the preventive treatment of all pregnant women with an antibiotic is not justified, the Haute Autorité de Santé recommends systematic screening. between 34 and 38 weeks of amenorrhea. This vaginal sample is most often taken during the last gynecological check-up. It should also be performed in case of premature labor or premature rupture of membranes.

In the event of a positive result, future mothers receive intravenous antibiotic treatment from the start of labor. This precaution considerably reduces the risk of transmission of the bacteria to the newborn.