What is the most common complication of Percutaneous Umbilical Blood Sampling (PUBS) procedure?

Most Common Complication of Percutaneous Umbilical Blood Sampling (PUBS)

The most common complication of Percutaneous Umbilical Blood Sampling (PUBS) is bleeding from the umbilical cord puncture site, which occurs in a significant percentage of cases but rarely requires immediate intervention. 1, 2

Complications of PUBS: Frequency and Severity

PUBS (also known as cordocentesis or funipuncture) involves ultrasound-guided needle insertion into the umbilical cord vessels to obtain fetal blood samples for diagnostic or therapeutic purposes. The procedure carries several potential complications:

Common Complications:

• Bleeding from puncture site: Most frequent complication 2
• Fetal bradycardia: Occurs in approximately 9.4% of cases, more common with repeated and prolonged punctures 3
• Hematoma formation at cord: Seen in about 1.5% of cases, especially when puncturing a free loop of cord 3

Serious but Less Common Complications:

• Procedure-related fetal death: Approximately 0.9-1% of cases 3
• Preterm premature rupture of membranes (PPROM): Can lead to preterm delivery
• Infection: Potential for vertical transmission of maternal infection

Risk Factors for Complications

The risk of complications increases significantly with:

1. Duration of procedure exceeding 10 minutes: Associated with higher rates of fetal death (8.96%) and bradycardia (20.73%) 3
2. More than 3 puncture attempts: Associated with 33.33% fetal death rate 3
3. Presence of fetal hydrops: Significantly increases complication rates (6.3% vs 2.0% without hydrops) 4
4. Operator experience: Less experienced operators have higher complication rates
5. Underlying fetal condition: Pathological pregnancies have higher mortality rates (11.24%) compared to presumed healthy fetuses (0.58%) 3

Recommendations to Minimize Complications

To reduce the risk of complications during PUBS:

• Procedure should be performed by highly experienced physicians at specialized perinatal centers 1
• Limit the number of punctures to a maximum of 3 3
• Keep procedure duration under 10 minutes 3
• Consider maternal anesthesia (used in 70% of cases in Japan) 2
• Carefully select appropriate cases, as risk is directly related to the severity of the underlying condition 1
• Optimal timing is between 17-40 weeks gestation 1

Clinical Perspective

Despite these complications, PUBS remains a valuable procedure with a high success rate (97-98%) 2. The overall mortality rate is approximately 5%, but mortality directly attributable to the procedure is around 1% 3. The risk-benefit ratio must be carefully considered for each case, particularly in fetuses with non-immune hydrops fetalis where the complication rate is significantly higher.

Important Caveat

It's worth noting that complications are more common when PUBS is performed for therapeutic purposes rather than purely diagnostic ones 1. This is an important consideration when counseling patients about the risks associated with the procedure.