The vast majority of unborn babies are usually positioned such that the head is located near the birth canal. This is the natural and optimal positioning for a normal delivery.
However, a small number of babies may be positioned bottom first towards the end of the pregnancy. This is referred to as breech presentation, and requires special planning for how the baby will be born.
There are many reasons why babies may be positioned with the bottom first. Your midwife or obstetrician will normally suspect that your baby is breech during antenatal care visits. An ultrasound scan is usually done to confirm the positioning and look for causative factors.
Possible reasons that might account for breech presentations include uterine fibroids, an abnormally placed placenta, and reduced or even increased amount of fluid around the baby. Premature babies and twins may also present bottom first. But for most cases, there is usually no apparent cause for a breech presentation.
Most babies in breech presentation will have moved to head first by the last three to four weeks of the pregnancy. Hence there is not much reason to worry about breech presentation, where there is no apparent cause, till about 37 weeks of pregnancy. Beyond this time, it becomes more unlikely that the baby will turn spontaneously to head first. Hence plans for delivery must be made.
Your obstetrician may suggest manually turning your baby to head first after the 37th week. Safety criteria for both you and your baby must be fulfilled first before this is recommended. The procedure is termed as external cephalic version (ECV), and is successful in about 50 per cent of cases.
Once the baby is turned to head first, you would then normally continue antenatal care and wait for spontaneous labour. Some babies will, however, return to a breech position even after a successful ECV.
If ECV is not for you, or becomes unsuccessful, decisions about your delivery must then be made. A Caesarean Section (CS) may be recommended. You may also have the choice to consider delivering your baby vaginally bottom first. You are more likely to have a successful vaginal breech delivery if your baby is not too big.
This option though has become rarer following scientific studies that favour CS delivery with breech presentations due to potential complications with a vaginal birth. Be sure to have a detailed discussion with your obstetrician about breech delivery options prior to making final decisions. What eventually matters is a safe delivery.