Main Trial of the Cesarean Section and Intestinal Flora of the Newborn Study

Inclusion Criteria: * non-eventful pregnancy * planned elective CS * Finnish language competency Exclusion Criteria: Mother: * maternal refusal * positive findings in screening samples * maternal antibiotic treatment within 4 weeks of delivery (excluding the antibiotic given immediately prior to clamping of the umbilical cord) * travel outside European Union during 3 months prior to delivery * CS after the onset of labor (non-elective CS) Newborn: * birth below 37 weeks of gestation * Apgar score of less than 8 * disturbances of neonatal adaptation (such as transient tachypnea of the newborn) * antibiotic treatment of the newborn before discharge