Newborns are at higher risk of bacterial infection. During the labor process and vaginal delivery, babies come in contact with bacteria that live in the vagina and the skin in the genital and rectal area. These bacteria can cause disease in women, most commonly urinary tract infections. However, these bacteria can cause more problems for pregnant women and infants. Some of these bacteria are especially prone to cause disease in newborn babies. These bacteria can also travel through the cervix and infect the amniotic fluid and the uterus (an infection called chorioamnionitis). This can be serious for both the mother and the baby.

Risk factors for infection in babies

Conditions that increase the risk of infection in babies include:

  • Rupture of membranes (“water broke”) 18 hours or more before delivery
  • Maternal fever (100.4° F or higher)
  • Maternal amniotic fluid infection (chorioamnionitis). Symptoms include uterine tenderness, fever, foul smelling amniotic fluid.
  • Premature birth (less than 37 weeks)
  • Maternal group B strep (GBS) colonization (see below). This includes a positive vaginal or rectal culture or rapid test, a urinary tract infection with GBS during pregnancy, or a previous infant with GBS infection.
  • The risk due to GBS decreases if the mother is treated with certain antibiotics during labor (see below).

Group B strep

Group B Streptococcus (Streptococcus agalactiae), also called group B strep or GBS, is a common bacteria that lives in human intestines and does not cause illness. In women, it can also live in the vagina, where it does not cause disease. It does, however, sometimes cause urinary tract infections in women.

While the bacteria is relatively harmless to adults, it can be very dangerous to babies. They can become infected during childbirth if the mother has the germ in her vagina or rectum. GBS can cause blood infection (sepsis), meningitis, pneumonia, and death.

National guidelines were developed in the 1990’s to prevent GBS disease in babies. There are two main components to the strategy:

  • All women are tested around 36 weeks of pregnancy to see if they have GBS bacteria living in their vagina or their rectum. The results of this test, along with a few other factors, determine if the baby is at risk or not.
  • Women who are at risk receive antibiotics during labor. If the antibiotics are started soon enough before delivery (usually 2 or more hours), then it has been shown to dramatically lower the risk of the baby becoming infected.

Management of babies at risk for infection

Several strategies for managing babies who are at higher risk of infection due to any of the risk factors above, especially GBS, have been developed over the years (1996-2019). However, unlike management of moms, doctors and hospitals are quite varied in their approach to managing infants.

After birth, some babies will be observed for 24 hours and some for 48 hours before going home. Some babies may be tested for infection with a blood culture and/or blood count (CBC). Some may receive antibiotics until the blood culture remains negative for 36-48 hours.

Guidelines published in 2019 recommend using computer algorithms to predict the risk of infection given all the baby’s risk factors. These have been proven to be very accurate. They predict which babies need testing and which need antibiotics. It has the benefit of more individualized care, less use of unnecessary antibiotics, less unnecessary testing, shorter hospital stays, and less separation of babies from their mothers.