Finding out you have a “strep” infection while pregnant can be concerning, but these infections are common and highly manageable with proper medical care. The term “strep” refers to bacteria in the Streptococcus family. During pregnancy, medical professionals focus on two distinct types: Group A Streptococcus (GAS) and Group B Streptococcus (GBS). GAS causes acute infections like strep throat, requiring immediate treatment to protect the parent’s health. GBS often lives harmlessly in the body but poses a risk to the newborn during delivery, necessitating a specific screening and prevention protocol.
Managing Acute Strep Throat (Group A Strep) During Pregnancy
Group A Strep (GAS), the cause of strep throat, presents as an acute infection with symptoms such as a sudden sore throat, fever, and sometimes a rash (scarlet fever). Pregnant individuals who suspect strep throat should seek prompt diagnosis, typically through a throat swab test, as untreated GAS carries risks for the parent. An untreated infection can lead to complications such as rheumatic fever, kidney inflammation, or sepsis.
The primary concern with any infection during pregnancy is high fever, which may pose a risk to the developing fetus, especially in the first trimester. Antibiotic treatment is necessary and safe for both the pregnant individual and the baby. Standard treatments, such as penicillin or amoxicillin, are first-line therapies because they have a long history of safe use in all trimesters. These antibiotics are classified as Category B drugs, meaning human data suggests they are safe.
A typical course of treatment involves taking the prescribed antibiotic for a full 10 days, even if symptoms resolve earlier. Completing the full course ensures the eradication of the bacteria and prevents long-term complications like rheumatic fever. If a pregnant person has a penicillin allergy, alternatives like cephalexin or clindamycin can be prescribed. Prompt and complete treatment manages an acute GAS infection and minimizes associated risks during pregnancy.
The Specific Concern of Group B Strep (GBS) Colonization
Group B Strep (GBS) is a type of bacteria commonly found in the gastrointestinal and genitourinary tracts of healthy adults. Unlike Group A Strep, GBS colonization is not usually an active infection causing symptoms in the pregnant individual. Approximately 10 to 30 percent of pregnant people carry GBS, and this colonization status can be intermittent.
GBS is monitored closely during pregnancy due to the risk of vertical transmission to the newborn. If the bacteria are present in the vagina or rectum during a vaginal birth, the baby can be exposed as they pass through the birth canal. This exposure can lead to Early-Onset GBS Disease (EOD) in the infant, which is a severe, potentially life-threatening infection. EOD can manifest as sepsis, pneumonia, or meningitis in the first week of life.
To identify this risk, universal screening for GBS is performed late in the third trimester, typically between 35 and 37 weeks of gestation. This screening involves a swab of the lower vagina and the rectum to check for the presence of the bacteria. The timing is chosen because a positive result during this window is the most accurate predictor of colonization status at the time of delivery. A positive test result means the bacteria are present and a plan for prevention must be established.
Protecting the Newborn: GBS Screening and Labor Management
If the GBS screening test is positive, or if certain risk factors are present, the standard protocol involves administering prophylactic intravenous antibiotics during labor. The goal of this intrapartum antibiotic prophylaxis (IAP) is to reduce the bacterial load in the birth canal just before delivery. Penicillin is the preferred antibiotic for IAP because it is highly effective against GBS.
For the treatment to be maximally effective, the pregnant person should receive the antibiotics for at least four hours before the baby is born. This four-hour window allows the medication to reach adequate levels in the blood and surrounding tissues. Receiving IAP has reduced the incidence of Early-Onset GBS Disease in newborns.
In cases of known penicillin allergy, alternative antibiotics like cefazolin or clindamycin are used, depending on the severity of the allergy. Treatment is also given to those who deliver prematurely before the 37-week screening can be completed or if GBS was found in the urine earlier in the pregnancy. Identifying colonization status and delivering timely antibiotics during labor minimizes the risk of GBS-related illness in the newborn.