Spontaneous umbilical artery thrombosis diagnosed in the third‐trimester: A case report

We present a case of spontaneous umbilical artery thrombosis diagnosed antenatally with ultrasonography in the third trimester.

Hospital.The mother provided written informed consent for the publication of the case detail.
A 22-year-old pregnant woman, G4P0, was admitted because of abdominal pain at 30 +1 weeks of pregnancy.Her past three pregnancies were all unplanned pregnancies and had ended with terminations in the first trimester.She had not used clexane during the pregnancy.The results of prenatal examination during pregnancy were normal.Ultrasound examination during the second trimester showed the normal number of umbilical vessels.The patient had no relevant medical history.Ultrasound pre-admission revealed a single umbilical artery and an abnormal hyperechoic mass measuring 3.2 × 0.8 cm inside the umbilical cord on transverse ultrasonography.Doppler ultrasound around the mass showed that the umbilical artery systolic to diastolic ratio was 2.92 and the peak velocity of systolic blood flow in the middle cerebral artery was 62.04 cm/s.Doppler ultrasound of the distal umbilical artery showed that the systolic to diastolic ratio was 2.29 and the peak systolic velocity was 23.04 cm/s (Figure 1).Pelvic examination showed that the cervix was dilated by 5 cm.She received corticosteroid therapy for fetal lung maturation after admission.The cardiotocogram was discontinuous and unsatisfactory because she was experiencing severe uterine contractions at that time.A male infant of normal appearance weighing 1480 g was delivered by vaginal delivery.The Apgar score was 4 at 1 min and 9 at 5 min.Cord blood pH test failed because the blood was coagulated.The placenta weighed 320 g, was discoid in shape and 15 × 14.5 × 2.5 cm in size.The umbilical cord had a paracentral insertion with a length of 85 cm, and was dark red in color.Thrombosis of umbilical cord vessels is rare, with an incidence of about 0.08% of pregnancies. 2Venous thromboses are more common than arterial thromboses.[4] The pathogenesis and mechanism of umbilical vascular thrombosis are not yet fully understood.Current thinking holds that anatomical cord dysplasia, abnormal length of the umbilical cord, or unusual Wharton jelly morphology may present a higher risk for occlusion of the umbilical cord.Diseases such as pregestational diabetes, hypertensive disorders, or thrombophilia, which may affect the state of the maternal circulation, are also potential factors in umbilical vascular thrombosis. 5 addition, umbilical artery thrombosis may also be related to infection, coagulation dysfunction, and smoking.Umbilical artery thrombosis can cause fetomaternal transfusion, intrauterine growth restriction, fetal death, meconium in the amniotic fluid, acute fetal distress during labor, neonatal organ infarction, and cerebral palsy. 6trasound is the first choice for prenatal detection of umbilical artery thrombosis.Ultrasound makes prenatal diagnosis of umbilical artery thrombosis possible by evaluating the cross section of the umbilical cord.When an umbilical artery is embolized and the blood flow is blocked, it is easy to misdiagnose this as a single umbilical artery.This requires doctors with wide clinical experience.They should compare the previous ultrasound results with the current images to avoid misdiagnosis.Klaritsch et al. 7 reported the characteristic ultrasound finding of umbilical artery thrombosis, the occluded artery in parallel with the remaining artery and surrounded by the umbilical vein, which appeared like "an orange grabbed by a hand".Umbilical artery thrombosis is rare and there is no consensus on clinical treatment.In view of the possible harm, the management of umbilical artery thrombosis may include planned elective delivery by cesarean section following antenatal corticosteroid therapy for fetal lung maturation. 8The local neonatal treatment level should be considered.When ultrasound detects a single umbilical artery for the first time in the third trimester, umbilical artery thrombosis should be strongly suspected.
In the case presented here, the patient was admitted to hospital because of preterm labor.The ultrasound showed a single umbilical artery as a result of an absence of blood flow in one of the two umbilical arteries, which prompted us toward a diagnosis of umbilical artery thrombosis.Due to the dilatation of the cervix, the woman gave birth by vaginal delivery soon after admission.Amniotic fluid culture was positive for Escherichia coli.
Placental pathologic examination revealed chorioamnionitis and umbilical artery thrombosis.The cause of the thrombosis may have been intrauterine infection.For umbilical artery thrombosis, most experts recommend cesarean section, but this patient had a vaginal delivery because of the rapid progress of labor after admission.
The umbilical cord had two arteries and one vein.The diameter of it near the fetus was 4 cm with an unusual Wharton jelly morphology (Figure2).The amniotic fluid was clear but a sample culture of it was positive for Escherichia coli.Pathologic examination of the cord and placenta revealed severe chorioamnionitis, one umbilical artery thrombosis with segmental vascular wall infarction and degenerative changes in the vascular wall of the umbilical artery (Figure3).Thorough evaluation of coagulant activity in the patient revealed no evidence of thrombophilia.Blood tests revealed no evidence of antiphospholipid syndrome or systemic lupus erythematosus.The F I G U R E 1 (a) Ultrasound image of umbilical artery thrombosis.An abnormal hyperechoic mass measuring 3.2 × 0.8 cm inside the umbilical cord on transverse ultrasonography.(b) Doppler ultrasound around the mass showed that the umbilical artery systolic to diastolic (S/D) ratio was 2.92 and the peak velocity of systolic blood flow in the middle cerebral artery (PSV) was 62.04 cm/s.(c) Doppler ultrasound of the distal umbilical artery showed that the S/D ratio was 2.29 and the PSV was 23.04 cm/s.F I G U R E 3 Microscope image of umbilical artery thrombosis; upon microscopic examination, a thrombosis was found in the umbilical artery.

F I G U R E 2
General image of umbilical cord.Unusual Wharton jelly morphology of the umbilical cord.babyunderwent blood culture and sputum culture in the neonatal intensive care unit and the results were negative.Coagulation function test was also normal and examination of antinuclear antibodies was negative.