An external version is a procedure in which your physician may attempt to rotate a baby that is breech or transverse.
During most of your pregnancy, your baby is completely free to move around within your uterus. Around week 32 or so, your baby will become so large that it cannot move around as much. It becomes much more difficult for your baby to turn over, so whatever position it is in by this point is likely to be the position it is in for delivery. Most babies settle into a head-down position. If a baby is positioned such that the buttocks lead the way out of the uterus, it is called a "frank breech." This is the most common type of breech birth.
The head-down position is the safest position for delivery. This is because the biggest part of your baby’s body is usually its head. If the head fits through your pelvis, then the rest of the its body should slip out fairly easily. If the fetus is born bottom first, it is possible that the body will fit through the mother’s pelvis, but the baby’s head will get stuck at the level of the chin. This condition, known as a trapped head, is very dangerous. If the baby’s head gets trapped, the possibility of injury is high. Once the baby’s body is born, the umbilical cord usually stops pulsating (just as it would during a normal delivery). This cuts off the oxygen supply from the mother to the baby. If the baby’s head is still inside the uterus the baby cannot yet breathe on its own. Therefore, it is essential to deliver the baby as quickly as possible.
Transverse position is a very serious presentation for your baby. When the baby is transverse, it means that your baby is laying across your tummy instead of the normal head down position. There are several causes for this transverse presentation. It is quite common where the womb is large and of poor tone, as in women who have had many babies, it also can occur in a similar situation where there is excessive birth fluid, or a multiple pregnancy. If the afterbirth is lying very low, covering the lower area of the womb, a transverse lie can also develop. In very rare cases, there may even be an abnormal development of the womb, which therefore prevents the baby from assuming the accepted position, or there may even be a reduced size of the bony birth canal – the pelvis- that will also encourage a transverse lie. Large fibroids in this lower part of the womb can also have a similar effect.
An external version is a procedure in which Your physician may be able to turn your baby into a more favorable position for birth. This procedure involves the physician moving the baby manually from the outside while using ultrasound to monitor the baby’s movement. There is some risk in an external version, because it is possible that it could cause the placenta to detach from the wall of the uterus. However, this risk is fairly low, and an external version is most often successful and will help avoid a cesarean section or breech birth.
Keep in mind that sometimes nothing will get a baby to turn, or a baby will be stubborn and turn back into the previous position after having turned head-down. For this reason, it is important to prepare yourself mentally and emotionally for the possibility of a cesarean section. Women who are prepared ahead of time for the possibility of a medically necessary cesarean section report having a more positive birth experience than those who thought that "it wouldn’t happen to me."