Cephalopelvic Disproportion (CPD) Injuries

In some cases, there is a size mismatch between the mother’s pelvis and the fetus’ head. This means that the baby’s head is proportionally too large to fit through the pelvic opening, stalling labor and requiring a C-section. Cephalopelvic disproportion (CPD) can be sometimes diagnosed before labor begins using ultrasound or pelvimetry (measurements of pelvic size) with an MRI, a pelvimeter, CT scan or X-ray. An attempt is sometimes made to attempt delivery because the pelvis can potentially separate enough to allow the fetal head through. If the attempt at delivery is unsuccessful, however, doctors should move on to a C-Section, as prolonged delivery in the presence of CPD may cause birth trauma.

Cephalopelvic disproportion (CPD) | Birth InjuryCephalopelvic disproportion (CPD) occurs in a pregnancy where there is mismatch in size between the baby’s head and the mother’s pelvis, resulting in an inability of the baby to pass safely through the birth canal.  This may be caused by the baby’s head outgrowing the size of the birth canal, or the baby presenting in a position that will not allow descent through the pelvis.  In CPD, the mother’s pelvis is usually too small for the baby to be delivered by a normal, spontaneous vaginal delivery. Cephalopelvic disproportion can cause prolonged labor, fetal distress and a delayed second stage of labor. In spite of prolonged pushing, there is inadequate progress of the baby through the birth canal. Sometimes, labor can be completely halted and a C-section is required. If not appropriately treated, the consequence is obstructed labor, which endangers the lives of both mother and baby. Conditions such as Erb’s palsy, hypoxic ischemic encephalopathy, or brain bleeds from prolonged labor, birth trauma, or a compressed umbilical cord/ cord prolapse may result.

Causes of Cephalopelvic Disproportion (CPD)

There are numerous causes for CPD, but the most frequent is a contracted pelvis with an average sized baby.  Some of the common causes for CPD include the following:

  • Large sized baby: This can be caused by gestational diabetes and other conditions that cause a baby to be macrosomic (weight is > 4000 or 4500 grams) or large for gestational age. Post-term pregnancies and hydrocephalus (fluid in the baby’s brain that leads to swelling) may also cause a baby to be large.
  • Contracted pelvis: This occus when a woman has a decrease of 1.5 to 2 cm in any important pelvic measurement (diameter).
  • Pelvic exostoses: These are bony growths on the pelvis.
  • Spondylolisthesis: This is a condition in which a bone in the spine slips out of its proper position onto the bone below it.
  • Unusual presentations: Brow presentation (brow of the fetus is lying over the opening of the pelvis); face presentation (baby’s face is lying over the opening of the pelvis), occipitoposterior positions (head of the baby is facing the base of the mother’s spine); deflexed head (baby’s head is lifted instead of flexed onto her chest; the baby’s chin is not tucked).

Some women are more prone to cephalopelvic disproportion. Risk factors include:

  • Mother older than 35
  • Mother shorter than 5’ 3”
  • Gestational age over 42 weeks
  • Osteomalacia of the pelvis (softening of the pelvic bones)
  • History of previous pelvis trauma, rickets or tuberculosis
  • History of tumors of the pelvic bone
  • Congenital deformity of the tailbone
  • Flattening of the anterior part of the pelvis, making for a triangular-shaped pelvis
  • Fibroid tumors of the uterus
  • Congenital vaginal septum (partition within the vagina)
  • A cervix that does not dilate properly

Diagnosing Cephalopelvic Disproportion (CPD)

Doctors may not always predict the presence of CPD. Listed below are several methods employed by physicians to try and assess the size of the pelvis and baby.

  • Pelvimetry by MRI: This is used to assess the dimensions of the pelvis, determine the baby’s position, and examine the soft tissues of the mother and baby.
  • Clinical pelvimetry: This is a process used to assess the size of the birth canal using the hands and/or with a pelvimeter.
  • Ultrasound: The baby’s head and body size are measured during a routine ultrasound examination. Measurements are compared against standardized growth charts to determine the relative risk of CPD by the time of delivery.
  • X-ray or CT pelvimetry: This is a radiographic examination used to determine the dimensions of the mother’s pelvis and the diameter of the baby’s head. The value of x-ray pelvimetry needs to be weighed against the risk of radiation exposure.

Although the techniques discussed may help the physician predict the presence of CPD, the medical standard for diagnosis of CPD is to attempt labor and delivery before proceeding to a C-section. Sometimes, the maternal pelvis is able to separate and stretch allowing the baby to pass through the birth canal even when a previous ultrasound had indicated a large fetal head.

The diagnosis can be made when the progress of labor stops or fails to follow the expected rate of descent.  When cervical dilatation stops or the baby fails to move down for a period of two hours or more is indication that a C-section is necessary.

Treatment for Cephalopelvic Disproportion (CPD)

The treatment for CPD is a C-section or symphysiotomy (surgical division of pubic cartilage) after a trial of labor.  When CPD is present, attempts to deliver the baby vaginally may cause undue trauma and permanent injury to the baby.

It may be beneficial for the physician to have the mother squat or assume another upright position during labor, as this affects pelvic measurements. Squatting increases pelvic capacity by nearly 30 percent.

Cephalopelvic Disproportion (CPD) and Birth Injuries

Physicians faced with CPD must be very skilled in treating this potentially dangerous condition.  Listed below are issues and complications that can occur when CPD is present.

When risk factors for CPD are present, it is essential that the physician monitor the mother and baby very closely and be prepared for a C-section delivery. In certain situations, an early delivery may even be necessary. It is negligence when a mother and baby are not properly assessed and monitored.  Failure to act skillfully and, if necessary, quickly, also constitutes negligence.  If this negligence leads to injury of the mother or baby, it is medical malpractice.

Legal Help for Cephalopelvic Disproportion (CPD) Injuries

Legal Help for Cephalopelvic Disproportion (CPD) InjuriesReiter & Walsh, P.C. was established to focus exclusively on birth injury cases. Since the firm’s inception in 1997, our legal team has addressed the specific needs of our clients in a variety of birth injury, pregnancy and newborn medical malpractice cases. Many of our cases involve delivery complications such as cephalopelvic disproportion (CPD), delayed delivery, C-section errors, hypoxic ischemic encephalopathy (HIE; birth asphyxia), and permanent brain damage. We’ve helped clients from all over the United States, in places including Michigan, Ohio, Pennsylvania, Texas, Tennessee, Wisconsin, Arkansas, Mississippi, Washington D.C., and more.

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Video: Cephalopelvic Disproportion (CPD) and Birth Injury

In this video, birth injury attorney Euel Kinsey discusses the causes, risk factors, and consequences of cephalopelvic disproportion (CPD).

How Do You Pronounce Cephalopelvic Disproportion?


  • Blackadar CS, Viera AJ. “A retrospective review of performance an”d utility of routine clinical pelvimetry.” Fam Med. 2004; 36:505-7.
  • Maharaj, D. “Assessing cephalopelvic disproportion: back to the basics.” Obstetrical & gynecological survey. 2010; 65(6): 387-395.
  • Tsvieli O, Sergienko R, Sheiner E. “Risk factors and perinatal outcome of pregnancies complicated with cephalopelvic disproportion: a population-based study.” Archives of gynecology and obstetrics. 2012; 285(4): 931-936.

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