Inclusion Criteria:
For the mother:
* Female 18-40 years of age who is in good general health, is fully able to provide consent to participate in the study, anticipates being available for the duration of the study, and is willing to comply with all study procedures
* Singleton pregnancy
* Completed ≧3 prenatal care visits at Vanderbilt University Medical Center (any facility)
* Having rectovaginal swabs collected at ≧36 weeks of gestation to screen for Group B Streptococcus (GBS) as part of prenatal screening tests
* Having a scheduled (planned or non-emergency) C-section at Vanderbilt University Medical Center (main campus only)
* No intent to relocate outside the middle Tennessee region within 12 months of recruitment
For the child:
* Estimated gestational age ≧37 weeks
* Birth weight ≧2,500 grams
Exclusion Criteria:
For the mother:
* Past medical history of any of the following:
* Previous child with GBS infection or prior positive GBS testing
* Hepatitis B, hepatitis C, or human immunodeficiency virus (HIV) infection
* Genital herpes simplex virus (HSV) infection, genital herpetic lesions, or prior positive genital HSV testing
* Genital human papilloma virus (HPV) infection, genital HPV lesions, or prior positive genital HPV testing
* Diabetes type I or type II
* Laboratory evidence during the current pregnancy of any of the following:
* GBS bacteriuria in urine samples collected at any time (performed as standard of care)
* GBS colonization in rectovaginal swabs collected at ≧36 weeks of gestation (performed as standard of care)
* Chlamydia, trichomoniasis, or gonorrhea in urine samples collected at ≧36 weeks of gestation (performed as part of the screening procedures for this study)
* Hepatitis B, hepatitis C, HIV, or syphilis in blood samples collected at ≧36 weeks of gestation (performed as part of the screening procedures for this study)
* Uncontrolled gestational diabetes
* Any serious obstetric disease (e.g., preeclampsia with severe features, placental abruption or severe bleeding, or thromboembolic disease) as deemed by the PI or co-investigators
* Prior abnormal Pap smear
* C-section scheduled for a genitourinary infection that would have interfered with vaginal delivery (e.g., genital herpetic lesions)
* Lack of available prenatal screening tests
* Use of systemic (i.e., oral, intramuscular, or intravenous) antibiotics in the 4 weeks prior to delivery (except for those being administered as part of the C-section)
* Use of systemic (i.e., oral, intramuscular, or intravenous) immunosuppressive, biologic, or chemotherapeutic agents in the 3 months prior to delivery (except for systemic immunosuppressive agents not being used for their immunosuppressive effects \[e.g., prenatal intramuscular beclomethasone for fetal lung maturation\])
* Fever (≧100.4°F \[38°C\]) in the 72 hours prior to delivery
* Symptoms (e.g., dysuria, pruritus, or discharge) suggestive of a genitourinary infection (e.g., bacterial vaginosis, vaginal yeast infection, chorioamnionitis, or urinary tract infection) on the day of delivery
* Symptoms (e.g., pain, tenderness, tingling, burning, itching, or swollen lymph nodes) suggestive of genital HSV infection on the day of delivery
* Other symptoms (e.g., new-onset rhinorrhea, sore throat, cough, body aches, chills, nausea, vomiting, or diarrhea) suggestive of an acute infectious disease on the day of delivery
* Physical exam findings (e.g., fever \[≧100.4°F (38°C)\] or vesicles, warts, or ulcers in the genital, perineal, or anal region) suggestive of a genitourinary infection on the day of delivery (performed as part of the screening procedures for this study if not performed as standard of care)
* Maternal vaginal pH\>4.5 on the day of delivery (performed as part of the screening procedures for this study)
* Need for a switch from a scheduled C-section to an emergency C-section
* Prelabor prolonged rupture of membranes (i.e., ≧18 hours prior to delivery)
* Pregnancy as the result of an assisted reproductive technology or surrogacy
* Participation in another clinical trial that involves an intervention that could impact the quality or interpretation of the study data as deemed by the PI or co-investigators
* Other past or current medical problems that could compromise the safety of participants, interfere with their ability to comply with study requirements, or impact the quality or interpretation of the study data as deemed by the PI or co-investigators
For the child:
* Need for neonatal measures outside routine clinical care (i.e., drying, tactile stimulation, bulb syringe or catheter suction of nose and mouth, or temperature maintenance) in the delivery room
* Transfer to the neonatal intensive care unit immediately after delivery
* Thick particulate meconium noted during delivery
* Physical exam findings (e.g., tachypnea, nasal flaring, retractions, cyanosis, or grunting) suggestive of neonatal acute respiratory distress immediately after delivery (performed as part of the screening procedures for this study)
* Prenatal diagnosis of a serious genetic, respiratory, cardiovascular, or neurological disease
* Prenatal diagnosis of intrauterine growth restriction
* Prenatal diagnosis of a major congenital anomaly (e.g., cleft lip or palate, cystic hygroma, or giant omphalocele)
* Participation in another clinical trial that involves an intervention that could impact the quality or interpretation of the study data as deemed by the PI or co-investigators
* Other past or current medical problems that could compromise the safety of participants, interfere with their ability to comply with study requirements, or impact the quality or interpretation of the study data as deemed by the PI or co-investigators
