Baby Too Big For Vaginal Birth? All You Need To Know About CPD

All mothers do know the benefits of vaginal birth and favor vaginal birth. However, there are several factors that hinder a vaginal birth. There is a common conception that the mother with wider hips can easily deliver a baby and on the other hand, one with a narrow hip ends up with a c section. Are you comparing your physical feature with others to know your chances of vaginal delivery?  Well, let you be tall or short, having large hip or narrow hip, irrespective of these factors, your body is designed to give birth. But, yes. The size does matter and some disproportions do hinder the normal vaginal delivery. Continue reading.

What is CephaloPelvic Disproportion?

Cephalopelvic disproportion (CPD) is a pregnancy complication in which there is a size mismatch between the mother's pelvis and the fetus' head.  This takes place when the baby is too big, the pelvis is too small, the baby is in an erroneous position, or the relationship between the baby and the pelvis is incorrect even though the baby is not too big and the pelvis is not too small. This can make a vaginal delivery risky or impractical.

How common in CPD?

Pelvic anomalies are the basic factor that brings about true CPD. In the early days, poor nutrition that resulted in rickets, and illnesses such as polio, lead to pelvic abnormalities and therefore, CPD's were quite common these days and it paved the way for quite a lot loss of life during the delivery process.

However, today, due to an improved lifestyle and nutrition, a true CPD is observed in instances where the mother has congenital abnormalities or severe injuries to the pelvis, like, a pelvic fracture during a traffic accident. True CPD is estimated to occur in about 1 out of 250 pregnancies

Are you wondering why we are mentioning "true CPD" more often? Well, the reason is that as our birth culture shifted to non-evidenced based practices, sometimes instances that described as CPD are usually the result of other things like failure to progress, which, in turn, is more often is actually, "failure to wait".

What are the risk factors CPD?

Though not common, there are certain factors that can cause CPD

  • Contracted pelvis in which the pelvis is smaller than the normal measurements in any of the pelvic measurements taken
  • History of previous pelvic trauma, rickets or tuberculosis
  • Pelvic exostoses, a rare medical condition in which multiple bony spurs or lumps develop on the pelvis
  • Spondylolisthesis,  A spinal disorder in which a bone (vertebra) slips out of its proper position onto the bone below it.
  • Health conditions like gestational diabetes, which cause a baby to be significantly bigger. The baby weighs more than 4.5 kg or large for gestational age.
  • Overdue pregnancy
  • Flattening of the anterior part of the pelvis, that gives pelvis a triangular shape.
  • Congenital deformity of the tailbone.
  • CPD is found to run in families. If your mother or sister bumps into it, your odds of having it increase.
  • Congenital vaginal septum, that is, a partition within the vagina.
  • Abnormal fetal position.

Can I prevent the possibility of CPD?

Actually, CPD's are not usually diagnosed with the progression of the pregnancy. It all comes down to a matter of the shape of pelvis and size of the baby, (both not under your direct control) and how the two match up when delivery starts to happen. Therefore, it cannot be prevented.

What are the complications of CPD?

The main Complications of CPD is an increased risk of C-section (Statistics suggest that about one out of 3 C-sections brings about by some sort of CPD). Other risks include shoulder dystocia as well as an increased risk of postpartum bleeding when attempting a vaginal delivery. Prolonged labor due to CPD may result in more critical birth injuries such as hypoxic-ischemic encephalopathy, a form of brain damage that take place when an infant's brain doesn't obtain enough oxygen and blood, and cerebral palsy. When there is decreased room in the uterus, either because of a large baby or a small maternal pelvis, oxygen deprivation may come about due to a compressed or prolapsed umbilical cord:

Do CPD Repeats in subsequent pregnancies?

Provided that the cause of CPD is not pelvic abnormalities, owing to the fact that the pelvis isn't a single fixed bone, its measurements can vary from one birth to another. According to a study published in the American Journal of Public Health, more than 65% of women who had been diagnosed with CPD in earlier pregnancies were capable to deliver vaginally in subsequent pregnancies