<unk> s 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,<unk> s 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<unk>  (or elective/scheduled<unk> , 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'<unk>  (delivery timed to suit the mother or hospital staff) or as a 'grade 3'<unk>  (no maternal or fetal compromise but early delivery needed). Emergency<unk> s are performed in pregnancies in which a vaginal delivery was planned initially, but an indication for<unk>  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<unk> s 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<unk>  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. The National Institute for Health and Care Excellence recommends that if after a woman has been provided information on the risk of a planned<unk>  and she still insists on the procedure it should be provided. If provided this should be done at 39 weeks of gestation or later. There is no evidence that ECS can reduce mother-to-child hepatitis B and hepatitis C virus transmission. By characteristics of the mother<unk>  delivery on maternal request<unk>  delivery on maternal request (CDMR) is a medically unnecessary<unk> , where the conduct of a childbirth via a<unk>  is requested by the pregnant patient even though there is not a medical indication to have the surgery. Systematic reviews have found no strong evidence about the impact of<unk> s for nonmedical reasons. Recommendations encourage counseling to identify the reasons for the request, addressing anxieties and information, and encouraging vaginal birth. Elective<unk> s at 38 weeks in some studies showed increased health complications in the newborn. For this reason ACOG and NICE recommend that elective<unk> s should not be scheduled before 39 weeks gestation unless there is a medical reason. Planned<unk> s may be scheduled earlier if there is a medical reason. After previous<unk>  Mothers who have previously had a<unk>  are more likely to have a<unk>  for future pregnancies than mothers who have never had a<unk> . There is discussion about the circumstances under which women should have a vaginal birth after a previous<unk> . Vaginal birth after<unk>  (VBAC) is the practice of birthing a baby vaginally after a previous baby has been delivered by<unk>  (surgically). According to the American College of Obstetricians and Gynecologists (ACOG), successful VBAC is associated with decreased maternal morbidity and a decreased risk of complications in future pregnancies. According to the American Pregnancy Association, 90% of women who have undergone<unk>  deliveries are candidates for VBAC. Approximately 60–80% of women opting for VBAC will successfully give birth vaginally, which is comparable to the overall vaginal delivery rate in the United States in 2010. Twins For otherwise healthy twin pregnancies where both twins are head down a trial of vaginal delivery is recommended at between 37 and 38 weeks. Vaginal delivery in this case does not worsen the outcome for either infant as compared with<unk> . There is controversy on the best method of delivery where the first twin is head first and the second is not. When the first twin is not head down at the point of labor starting, a<unk>  should be recommended. Although the second twin typically has a higher frequency of problems, it is not known if a planned<unk>  affects this. It is estimated that 75% of twin pregnancies in the United States were delivered by<unk>  in 2008. Breech birth A breech birth is the birth of a baby from a breech presentation, in which the baby exits the pelvis with the buttocks or feet first as opposed to the normal head-first presentation. In breech presentation, fetal heart sounds are heard just above the umbilicus. Babies are usually born head first. If the baby is in another position the birth may be complicated. In a 'breech presentation', the unborn baby is bottom-down instead of head-down. Babies born bottom-first are more likely to be harmed during a normal (vaginal) birth than those born head-first. For instance, the baby might not get enough oxygen during the birth. Having a planned<unk>  may reduce these problems. A review looking at planned<unk>  for singleton breech presentation with planned vaginal birth, concludes that in the short term, births with a planned<unk>  were safer for babies than vaginal births. Fewer babies died or were seriously hurt when they were born by<unk> . There was tentative evidence that children who were born by<unk>  had more health problems at age two.<unk> s caused some short-term problems for mothers such as more abdominal pain. They also had some benefits, such as less urinary incontinence and less perineal pain. The bottom-down position presents some hazards to the baby during the process of birth, and the mode of delivery (vaginal versus<unk>  is controversial in the fields of obstetrics and midwifery. Though vaginal birth is possible for the breech baby, certain fetal and maternal factors influence the safety of vaginal breech birth. The majority of breech babies born in the United States and the UK are delivered by<unk>  as studies have shown increased risks of morbidity and mortality for vaginal breech delivery, and most obstetricians counsel against planned vaginal breech birth for this reason. As a result of reduced numbers of actual vaginal breech deliveries, obstetricians and midwives are at risk of de-skilling in this important skill. All those involved in delivery of obstetric and midwifery care in the UK undergo mandatory training in conducting breech deliveries in the simulation environment (using dummy pelvises and mannequins to allow practice of this important skill) and this training is carried out regularly to keep skills up to date. Resuscitative hysterotomy A resuscitative hysterotomy, also known as a peri-mortem<unk>  delivery, is an emergency<unk>  delivery carried out where maternal cardiac arrest has occurred, to assist in resuscitation of the mother by removing the aortocaval compression generated by the gravid uterus. Unlike other forms of<unk> , the welfare of the fetus is a secondary priority only, and the procedure may be performed even prior to the limit of fetal viability if it is judged to be of benefit to the mother. Other ways, including the surgery technique There are several types of<unk>  <unk> . An important distinction lies in the type of incision (longitudinal or transverse) made on the uterus, apart from the incision on the skin: the vast majority of skin incisions are a transverse suprapubic approach known as a Pfannenstiel incision but there is no way of knowing from the skin scar which way the uterine incision was conducted. * The classical<unk>  involves a longitudinal midline incision on the uterus which allows a larger space to deliver the baby. It is performed at very early gestations where the lower segment of the uterus is unformed as it is safer in this situation for the baby: but it is rarely performed other than at these early gestations, as the operation is more prone to complications than a low transverse uterine incision. Any woman who has had a classical<unk>  will be recommended to have an elective repeat<unk>  in subsequent pregnancies as the vertical incision is much more likely to rupture in labor than the transverse incision. * The lower uterine segment<unk>  is the procedure most commonly used
Caesarean section
Labor induction
Natural childbirth
Forceps
Trial of labour
Cordotomy
Obstetrical forceps
Vaginal delivery