If the ultrasound shows that the baby is in breech or transverse position, there is no need to be nervous because the fetus is smaller in this week and the amniotic fluid is relatively large, so the baby has more room to move around in the womb and can “turn over” at any time. Later on, as the baby grows bigger and bigger, because of gravity and the relative decrease of amniotic fluid, the baby has less space to move around and in order to be comfortable, the baby will turn to the same direction as the mother’s body. About 7-16% of fetuses are still in breech position, and some of them may turn to head position later on their own. Only 3-4% of fetuses remain in breech position at 37 weeks of gestation. Some risk factors may cause the baby to remain in breech position at full term, such as: 1) uterine anomalies, uterine fibroids and other uterine abnormalities; 2) placenta abnormalities such as placenta praevia, placenta attached to the horn of the uterus; 3) too much or too little amniotic fluid; 4) pelvic stenosis of the mother; 5) anencephaly, hydrocephalus, sacrococcygeal teratoma and cervical mass; 6) fetal neurological damage; 7) fetal extension of the legs; 8) short umbilical cord; and 8) short umbilical cord. 8, short umbilical cord; 9, fetal growth restriction; 10, multiple births resulting in laxity of the abdominal wall and a more rounded uterine cavity; 11, previous history of breech presentation; 12, preterm birth; 13, advanced maternal age; however, most breech positions may occur randomly, which means that the cause cannot be found. If you are still breech at full term, you will need to discuss the mode of delivery with your doctor. Some hospitals perform “external inversion”, which is a series of operations on the abdomen of the pregnant woman to change the fetal previa from breech (or foot) to head, which avoids the need for a cesarean section and improves maternal and fetal complications during labor. This is an ancient technique that has been gradually discontinued since the 1980s due to the high number of cesarean deliveries. In the last decade it has been carried out again due to the promotion of natural childbirth and the liberalization of the second child and the increased demand for people wanting to give birth on their own. External inversion is not suitable for all breech pregnancies and requires good indications and contraindications, and close monitoring after successful inversion. The risk of neonatal asphyxia and birth injury during vaginal delivery is higher in breech-first fetuses than in cephalic vaginal deliveries. Because the breech circumference is generally smaller than the head circumference, there is a risk that the head will not be delivered successfully after the breech delivery. There are different types of breech presentation. If the fetus is single breech or full breech presentation during delivery, the breech circumference plus the circumference of the legs is larger, and the head and shoulders are more likely to pass through the birth canal first, but there is also a risk of birth injury and asphyxia. In case of incomplete breech presentation, such as unipedal or bipedal presentation, it is necessary to first fully “block the breech” by allowing the baby to flex the knee and hip joints, that is, to make the baby “sit cross-legged” to increase the diameter so that the cervix and birth canal can be fully dilated. During this process, the risk of fetal hypoxia, neonatal asphyxia, birth injuries such as brachial plexus injury, sternocleidomastoid injury, and cord prolapse are all increased. The experience and skills of the obstetrician and midwife are very much tested during a breech delivery, as it is necessary to accurately assess when to stop “blocking” and let the fetus be delivered, and when to continue “blocking”. Due to the risks of a breech vaginal delivery, if the external reversal fails, or if the pregnancy is not suitable for external reversal, or if there is fear of the risks of a vaginal delivery, a cesarean section is usually performed, usually at around 39 weeks of pregnancy.