Infant Microbiota Restoration With Maternal Microbes

Inclusion Criteria: * Healthy mother and healthy pregnancy * Singleton pregnancy, * Mothers who speak Finnish or Swedish * Mothers who are planning to breastfeed or give breastmilk by bottle to the infant * Infants who are expected to be healthy and who will not require BCG vaccination. Exclusion Criteria: * Participants who lives further than a 2-hour drive from Meilahti, Helsinki, Finland * Mothers who are not planning to breastfeed or feed breastmilk by bottle to the infant * Mothers who are diagnosed with gestational diabetes, pre-eclampsia or who have been receiving antibiotics during the pregnancy or delivery * Premature infants born before the pregnancy week 37 * Infants, who are born by urgent cesarean section or emergency cesarean section * Infants, who receive antibiotics during the first week of life * Infants, who are diagnosed with a disease, congenital anomaly or who receive less than 9 Apgar points at 5 minutes. * Infants, who receive BCG-vaccine