claims babies born via caesarean section have lower levels of Bacteroides that is linked to peanut allergy in infants. Classification Caesarean sections have been classified in various ways by different perspectives. One way to discuss all classification systems is to group them by their focus either on the urgency of the procedure (most common), characteristics of the mother, or as a group based on other, less commonly discussed factors. By urgency Conventionally, caesarean sections are classified as being either an elective surgery or an emergency operation. Classification is used to help communication between the obstetric, midwifery and anaesthetic team for discussion of the most appropriate method of anaesthesia. The decision whether to perform general anesthesia or regional anesthesia (spinal or epidural anaesthetic) is important and is based on many indications, including how urgent the delivery needs to be as well as the medical and obstetric history of the woman. Regional anaesthetic is almost always safer for the woman and the baby but sometimes general anaesthetic is safer for one or both, and the classification of urgency of the delivery is an important issue affecting this decision. A planned caesarean (or elective/scheduled caesarean), arranged ahead of time, is most commonly arranged for medical indications which have developed before or during the pregnancy, and ideally after 39 weeks of gestation. In the UK, this is classified as a 'grade 4' section (delivery timed to suit the mother or hospital staff) or as a 'grade 3' section (no maternal or fetal compromise but early delivery needed). Emergency caesarean sections are performed in pregnancies in which a vaginal delivery was planned initially, but an indication for caesarean delivery has since developed. In the UK they are further classified as grade 2 (delivery required within 90 minutes of the decision but no immediate threat to the life of the woman or the fetus) or grade 1 (delivery required within 30 minutes of the decision: immediate threat to the life of the mother or the baby or both.) Elective caesarean sections may be performed on the basis of an obstetrical or medical indication, or because of a medically non-indicated maternal request. Among women in the United Kingdom, Sweden and Australia, about 7% preferred caesarean section as a method of delivery. In cases without medical indications the American Congress of Obstetricians and Gynecologists and the UK Royal College of Obstetricians and Gynaecologists recommend a planned vaginal delivery.