What are the different types of umbilical cord prolapse in a pregnant patient?

Types of Umbilical Cord Prolapse

Umbilical cord prolapse should be classified into three distinct categories based on the positional relationship among the cord, fetal presenting part, and cervix: cord prolapse (cord descends below the presenting part), cord presentation (cord lies between the presenting part and cervix), and compound cord presentation (cord lies alongside the presenting part). 1

Classification System

1. Cord Prolapse (Overt Prolapse)

• The umbilical cord descends below the fetal presenting part and through the cervix 1
• Can occur with either ruptured or intact membranes 1
• The cord may be palpable or visible within the vagina or protruding beyond the introitus 1, 2
• Carries the highest fetal risk among all cord position abnormalities 1
• Associated with severe, rapid fetal heart rate decelerations 3

2. Cord Presentation

• The cord lies between the fetal presenting part and the cervix, but has not descended below the presenting part 1
• Can occur with either ruptured or intact membranes 1
• The cord remains above the level of the presenting part 1
• Carries intermediate fetal risk, less than overt prolapse but more than compound presentation 1

3. Compound Cord Presentation

• The cord lies alongside the fetal presenting part rather than below it 1
• This term replaces the outdated and misleading term "occult cord prolapse" 1
• Can occur with either ruptured or intact membranes 1
• Carries the lowest fetal risk among the three categories 1
• The misnomer "occult cord prolapse" should be abandoned because in true occult cases, the cord remains above the cervix and does not constitute actual prolapse 1

Clinical Significance by Type

The distinction between these three types is critical because fetal risk stratification differs substantially: cord prolapse represents the highest emergency requiring immediate delivery, cord presentation requires close monitoring and preparation for urgent intervention, and compound cord presentation may allow for more measured management depending on fetal heart rate patterns 1. The incidence of umbilical cord prolapse ranges from 1 to 6 per 1000 pregnancies, with perinatal mortality ranging from 6-10% in high-income countries to 23-27% in low-income settings 1, 2.

Common Pitfalls

Avoid using the term "occult cord prolapse" as it creates confusion—if the cord is truly occult (hidden above the cervix), it is not a prolapse at all but rather a cord presentation or compound presentation 1. The key distinguishing feature is whether the cord has descended below the presenting part (true prolapse) versus remaining alongside or above it 1.