Is fetal cerebral vascular resistance affected by the presence of nuchal cord(s) in the third trimester of pregnancy?

OBJECTIVE

To assess whether fetal cerebral vascular resistance is affected by the presence of nuchal cord(s) in the third trimester.

METHODS

A set of 115 patients with well-established dates and singleton, appropriate for gestational age (GA), non-anomalous fetuses with nuchal cord(s) diagnosed with prenatal color Doppler imaging, between 28 and 41 weeks and 115 controls matched for GA, were studied. Patients with hypertension, diabetes and autoimmune conditions were excluded. Doppler indices were obtained from the umbilical artery (UA) and the fetal middle cerebral artery (MCA) upon initial diagnosis of the nuchal cord.

RESULTS

Of 115 GA-matched pairs of pregnancies, 103 fetuses had a single nuchal cord and 12 a double nuchal cord. No significant differences were noted in patient age, gravidity, parity, sonographically estimated fetal weight (SEFW), and growth centile at ultrasonographic diagnosis. Mean UA systolic/diastolic ratio (S/D) was 2.28 +/- 0.32 and 2.36 +/- 0.33 (P = 0.03) and UA resistance index (RI) 0.55 +/- 0.06 and 0.57 +/- 0.06 (P = 0.02) among study and controls, respectively. Mean fetal MCA S/D and RI did not differ significantly between the two groups (fetal MCA S/D 5.01 +/- 1.28 and 5.04 +/- 1.71 (P = 0.86), and mean fetal MCA RI 0.78 +/- 0.06 and 0.78 +/- 0.05 (P = 0.88)). No significant differences were noted in GA at delivery, incidence of meconium-stained amniotic fluid, birth weight, mode of delivery, neonatal gender, 1 and 5 minute Apgar scores, or UA pH and base excess, between study and control patients.

CONCLUSION

Fetal cerebral vascular resistance is not affected by the presence of nuchal cord(s) in the third trimester of pregnancy.