What are the management and delivery recommendations for a pregnancy with a hypercoiled umbilical cord?

Management of Hypercoiled Umbilical Cord in Pregnancy

In pregnancies with isolated hypercoiled umbilical cord without fetal growth restriction or abnormal Doppler findings, expectant management with increased fetal surveillance is appropriate, with delivery timing based on standard obstetric indications; however, when hypercoiling is associated with fetal growth restriction and abnormal umbilical artery Doppler studies, delivery timing should follow established protocols for FGR management.

Understanding Hypercoiled Umbilical Cord

• A hypercoiled umbilical cord is defined as more than 1 coil per 5 cm (coil index >0.3 coils/cm), compared to the normal coil index of 0.2 ± 0.1 coils/cm 1
• Hypercoiling is present in approximately 21% of pregnancies and represents a chronic condition established in early gestation 1
• The condition can cause umbilical cord blood flow restriction leading to fetal vascular malperfusion, which in severe cases may result in intrauterine fetal demise 2, 3

Risk Assessment and Associated Complications

Key adverse outcomes associated with hypercoiled cords include:

• Fetal demise occurs in 37% of cases with overcoiled cords 1
• Fetal intolerance to labor in 14% of cases 1
• Intrauterine growth restriction in 10% of cases 1
• Association with umbilical venous thrombosis, thrombosis of chorionic plate vessels, and cord stenosis 1

Surveillance Protocol

For hypercoiled cord with normal fetal growth and normal Doppler:

• Weekly non-stress testing after viability is suggested 4
• Serial growth ultrasounds every 3-4 weeks to monitor for development of growth restriction
• Umbilical artery Doppler assessment should be performed if growth restriction develops 4

For hypercoiled cord with fetal growth restriction:

• Once FGR is diagnosed, serial umbilical artery Doppler assessment should be performed to assess for deterioration 4
• With decreased end-diastolic velocity (flow ratios >95th percentile) or severe FGR (EFW <3rd percentile), weekly umbilical artery Doppler evaluation is suggested 4
• Weekly cardiotocography testing after viability for FGR without absent/reversed end-diastolic velocity (AEDV/REDV), with increased frequency when complicated by AEDV/REDV 4

Atypical Hemodynamic Pattern Recognition

Critical finding in hypercoiled cords with FGR:

• An "atypical" hemodynamic pattern may occur showing normal impedance to flow in the utero-placental district but abnormal venous umbilical cord pulsatility with flow velocity higher than the umbilical artery 5
• The ductus venosus may show reduction of forward flow and/or reverse flow during atrial contractions despite normal placental Doppler 5
• This pattern indicates high hypoxic risk even without signs of placental insufficiency 5

Delivery Timing Recommendations

For isolated hypercoiled cord without FGR or abnormal Doppler:

• Delivery at 39-40 weeks following standard term delivery guidelines
• Consider delivery at 38-39 weeks if additional risk factors are present

For hypercoiled cord with FGR and normal umbilical artery Doppler:

• Delivery at 38-39 weeks of gestation when EFW is between 3rd and 10th percentile 4

For hypercoiled cord with FGR and abnormal umbilical artery Doppler (decreased diastolic flow but no AEDV/REDV):

• Delivery at 37 weeks of gestation is recommended (GRADE 1B) 4
• This also applies to severe FGR with EFW <3rd percentile 4

For hypercoiled cord with FGR and AEDV:

• Delivery at 33-34 weeks of gestation is recommended (GRADE 1B) 4
• Doppler assessment up to 2-3 times per week is recommended 4

For hypercoiled cord with FGR and REDV:

• Delivery at 30-32 weeks of gestation is recommended (GRADE 1B) 4
• Hospitalization, antenatal corticosteroids, and heightened surveillance with cardiotocography at least 1-2 times per day is suggested 4

Mode of Delivery Considerations

Cesarean delivery should be strongly considered when:

• FGR is complicated by AEDV/REDV of the umbilical artery, as growth-restricted fetuses with these findings have 75-95% rates of intrapartum fetal heart rate decelerations requiring cesarean delivery 4
• The atypical hemodynamic pattern with severe venous system alterations is present 5
• Early-onset IUGR with "brain sparing," severe reverse flow in ductus venosus, and absent diastolic flow in umbilical arteries is documented 5

Vaginal delivery may be attempted when:

• Hypercoiling is isolated without FGR or abnormal Doppler findings
• Continuous electronic fetal monitoring during labor is mandatory given the 14% risk of fetal intolerance to labor 1

Antenatal Corticosteroids and Neuroprotection

• Antenatal corticosteroids are recommended if delivery is anticipated before 33 6/7 weeks or between 34 0/7 and 36 6/7 weeks in women at risk of preterm delivery within 7 days who have not received a previous course (GRADE 1A) 4
• Intrapartum magnesium sulfate for fetal neuroprotection is recommended for pregnancies <32 weeks of gestation (GRADE 1A) 4

Critical Pitfalls to Avoid

• Do not assume normal placental function based solely on normal uterine artery Doppler - hypercoiled cords can cause fetal vascular malperfusion independent of placental insufficiency 5
• Do not delay delivery in the presence of abnormal venous Doppler findings - the atypical hemodynamic pattern indicates high hypoxic risk 5
• Do not underestimate the risk of acute decompensation - hypercoiling is associated with both chronic effects (growth restriction) and acute effects (fetal intolerance to labor and fetal demise) 1

Counseling for Future Pregnancies

• Rare cases of recurrent second trimester fetal demise due to hypercoiled cords have been reported, suggesting a possible genetic etiology in a subset of cases 2, 3
• In cases of recurrent pregnancy loss with documented hypercoiling, genetic counseling and consideration of early surveillance in subsequent pregnancies may be warranted 2, 3