One of the first things that women often think about after a cesarean birth is...was it necessary. There are four cut-and-dried situations, where surgical birth is absolutely necessary for the survival of the mother or baby or both. These are placenta previa, transverse presentation, true cephalopelvic disproportion and prolapsed cord during the first stage of labour. But in addition to these four conditions is a grey area where a cesarean may be in the best interest of the mother and baby. These conditions should be discussed completely with your doctor. You may even want to get a second opinion to be certain that you are comfortable with your choice. Or you may simply trust that your doctor wants what is best for you and your baby. These conditions are much more common and the cause of most cesareans.

Relative cephalopelvic disproportion: Unlike true CPD where you can never deliver a baby vaginally, relative CPD means you can not deliver this baby vaginally. Most often relative CPD will be diagnosed after you have laboured for sometime and your doctor has given your body a chance to birth your baby vaginally.

There are a couple of possible reasons for this. First, perhaps this baby is simply too large for your pelvis. My first cesarean was for this reason; my son weighed almost ten pounds. I spent five years angry at my doctor and feeling as if I had failed. But with my second VBAC, his brother who was a pound smaller got stuck at the shoulders (shoulder dystocia), a very serious emergency. In that moment, I was granted what few women have the gift of hindsight to know that my cesarean was absolutely positively necessary. I had successfully delivered an eight pound baby vaginally, but my pelvis simply was not large enough to easily accommodate a nine or ten pound baby. A couple of clues that you may have relative CPD are 1) Your baby's head never descends into your pelvis. You may hear your doctor or midwives discussing your baby being at a negative station. 2) Ultrasound can also sometimes be used to estimate your baby's size. Be aware that this is not always accurate. And this is a relative issue; while my sons had difficulty passing through my pelvis I had a friend who easily delivered an eleven baby.

The second reason for relative CPD is covered in more detail below.

Malposition: In order for your baby's head to pass through your pelvis the smallest diameter of its head must align with the largest diameter of your pelvis. The optimum position for this is when its chin is tucked to its chest. But sometimes a baby will instead lean its head back as if looking up (called a brow presentation). This makes it much harder for the head to fit through the narrow opening of the pelvis.

Likewise the best position for early labour is for the baby's face to be facing your bottom. This is because the face is softer and can more easily squeeze through the pelvis. But if the back hard part of the baby's head is pressed against your spine, called occiput posterior (OP), then you may experience very painful and slow back labour. This intense pain is caused by the rubbing of the two hard surfaces together. The labour may be slower because in this position as in relative CPD the baby's head is not in direct contact with your cervix, which means that the head is not putting pressure on the cervix to open.

Remember malposition is not an absolute indicator for a cesarean birth. Sometimes the baby's position will change during the labour and sometimes you or your health provider can use techniques to change your baby's position. But likewise, there are times when none of that works. My second cesarean birth was the result of OP. I had fabulous and supportive midwives. I tried all the common remedies to relieve the pain and speed up labour (the shower, walking, back massage) and nothing worked. I never for one moment doubted that this cesarean was necessary because I knew that I had reached my limit.

Breech position: Closely related to malposition is the situation where the baby is turned so that its bottom rather than its head is the presenting part. There is some increased risk of the baby getting stuck in the birth canal, if the head is larger than the bottom. For this reason, many doctors believe it is safer to deliver surgically. A couple of things to consider though is that the baby may change position either before or during labour. Sometimes babies can even be encouraged to move through a process called external version, but it is important that this is tried only by trained medical personnel under close monitoring. Even if the baby does not change position, it is still possible to have a natural breech birth. But this should be a joint decision with your medical team. You may even need to seek a care giver with more experience in breech deliveries.

Maternal exhaustion: Reaching your limits is another relative indicator for a cesarean. Sometimes we simply cannot go on. Did we fail somehow? No, we tried our best and then we used the help available to do what was best for us and our babies. Each woman and each labour has different limits. It is common for all women to reach this point during labour. Usually it is a sign that her cervix is almost completely dilated and her baby will be born soon. But if you have reached this point and you are still likely to be several hours from the birth discuss your options with your midwife or doctor.

Failure to progress: Referred to as dystocia of labour, this term carries with it some strong emotional ties...failure to progress. What it actually means is that for some reason your body is not labouring in a way that the doctor or midwife considers normal. Alone this may be the weakest indicator for a cesarean. But dystocia of labour is often seen in combination with maternal exhaustion or foetal distress (that we will discuss next). These then become the key indicators.

Foetal distress: Foetal distress is one of the most common reasons given for cesarean birth. Most often foetal distress is suggested by changes in the baby's heart beat on monitors. In the past twenty-five years, the use of monitoring equipment has dramatically increased during labour and with it the cesarean rate. Common changes that may indicate distress are beating too fast (tachycardia) or too slow (bradycardia). Another common pattern is called late decelerations. It is common for the baby's heart rate to slow during contractions, but it will come back up once the contraction is over. In a late deceleration, the heart rate comes up slowly or not at all. The thing to remember with foetal distress is that sometimes a baby that is diagnosed with distress is born with no problems. But as the parents except in the most dire situation you will need to weigh the risks of continuing to labour against the risks to your baby.

Prolapsed cord in second stage: As with the earlier discussion of cord prolapse, this is a serious and life-threatening situation for your baby. But if you are fully dilated and already pushing sometimes your doctor may feel that it would be better to perform an episiotomy (a cut between the vagina and anus) and use either forceps or vacuum extractor. It is often a question of which the doctor feels will get your baby out fastest in this critical situation.

Past obstetric history (previous cesareans): In 1986, when I had my first cesarean I was told that I would always have to have my babies via cesarean. Today though there is ample research showing that not only is Vaginal Birth After cesarean (VBAC) safe, but it is often better for the mother and the baby. The reason for the old saying once a cesarean always a cesarean was the fear that during labour the previous scar would separate. Research though has shown that this is extremely rare. As a result, many doctors now encourage their clients to deliver subsequent babies vaginally. Many women who have cesareans often want to have vaginal births with future pregnancies as well. If this is the case, the first step is to carefully select a doctor or midwife who is experienced with VBACs and a birth place that is VBAC friendly.

Birth choice: A growing number of women are making the choice to have an elective cesarean birth either following a traumatic first birth or due to deep set concerns about their safety of that of their baby. While it is the duty of your medical provider to provide you all information and to get your fully informed consent, please remember it is still your birth and ultimately your choice alone to make. This is a very personal decision and one that you should make with your doctor.

If you find yourself facing any of these situations during or before labour, a good question to ask is...do we have time to talk about it? This question will give you an indicator of how serious the doctor feels the situation has become. If the answer is yes, then a good follow up question is...what happens if we do nothing at this point? Perhaps your doctor will feel comfortable with changing your position and watching to see if the situation improves. But this is your baby and perhaps you feel that the best approach is to immediately follow your doctor's advice.

But as I said at the beginning of this article, these situations are relative. They are about pro's and con's, weighing options, and deciding what is best for you and your baby in your unique situation. While your medical team can and should offer expert guidance, ultimately you are in the best position to decide what is best for you and your child. But remember too that you are always assuming personal responsibility for the choices you make. It is just the first of too many difficult and sometimes life-and-death decisions you will have to make on behalf of your child in the years to come.