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Ultraschall Med 2022; 43(03): 298-303
DOI: 10.1055/a-1205-0411
Original Article

Antenatal Detection of True Knot in the Umbilical Cord – How Accurate Can We Be?

Pränataler Nachweis eines echten Nabelschnurknotens – Wie treffsicher sind wir?
Alina Weissmann-Brenner‡
1   Obstetrics and Gynecology, Chaim Sheba Medical Center, Ramat Gan, Israel
2   Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
,
Noam Domniz‡
1   Obstetrics and Gynecology, Chaim Sheba Medical Center, Ramat Gan, Israel
2   Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
,
Tal Weissbach
1   Obstetrics and Gynecology, Chaim Sheba Medical Center, Ramat Gan, Israel
2   Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
,
Shalev Mazaki-Tovi
1   Obstetrics and Gynecology, Chaim Sheba Medical Center, Ramat Gan, Israel
2   Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
,
Reuven Achiron
1   Obstetrics and Gynecology, Chaim Sheba Medical Center, Ramat Gan, Israel
2   Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
,
Boaz Weisz
1   Obstetrics and Gynecology, Chaim Sheba Medical Center, Ramat Gan, Israel
2   Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
,
Eran Kassif
1   Obstetrics and Gynecology, Chaim Sheba Medical Center, Ramat Gan, Israel
2   Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Abstract

Background Umbilical cord knot (UCK) is associated with increased risk of fetal death, but is usually diagnosed only after delivery. Our objective was to examine the accuracy of prenatal ultrasound in the diagnosis of UCK and the outcomes of these pregnancies.

Methods A prospective study was performed on 56 patients in which UCK was suspected during a routine level-II anatomical scan (study group). Data included demographics, pregnancy outcome, and short-term neonatal follow-up. The control group included pregnant women with normal pregnancy without UCK in a 4:1 ratio matched for gestational age at delivery.

Results True knot was observed postnatally in 54 out of 56 fetuses (detection rate of 96.4 %). Gestational age at diagnosis of UCK was 22.1 ± 3.1 weeks. The female to male ratio was 1:1 in both groups. Maternal age and parity were significantly higher in pregnancies with UCK compared to controls. The mean gestational age at delivery was 37.1 weeks of gestation in the UCK group. There was no difference in the birthweight percentile. 47 patients (87 %) underwent induction of labor. There were no differences in the rate of cesarean section or Apgar scores. No neonate with UCK needed ventilation. None suffered from seizures and none needed brain imaging. There were no cases of fetal or neonatal death in the pregnancies with UCK.

Conclusion There is a high detection rate of UCK during targeted scan of the umbilical cord performed during the level-II anatomical scan. Careful pregnancy follow-up and early term delivery may result in excellent obstetrical outcomes.

Zusammenfassung

Hintergrund Der Nabelschnurknoten (UCK) ist mit einem erhöhten Risiko für intrauterinen Fruchttod verbunden, wird jedoch normalerweise erst nach Entbindung diagnostiziert. Unser Ziel war es, die Genauigkeit des pränatalen Ultraschalls bei der Diagnose des UCK und das Schwangerschafts-Outcome zu untersuchen.

Methoden Eine prospektive Studie wurde an 56 Patienten durchgeführt, bei denen ein UCK während eines routinemäßigen anatomischen Scans der Stufe II (Studiengruppe) vermutet wurde. Die Daten umfassten demografische Daten, den Schwangerschaftsausgang und eine kurzfristige Nachbeobachtung von Neugeborenen. Die Kontrollgruppe umfasste schwangere Frauen mit normaler Schwangerschaft ohne UCK in einem Verhältnis von 4:1, mit Matching nach Schwangerschaftswoche bei Entbindung.

Ergebnisse Echte Knoten wurden postnatal bei 54 von 56 Föten beobachtet (Nachweisrate 96,4 %). Das Gestationsalter bei Diagnose des UCK betrug 22,1 ± 3,1 Wochen. Die Weiblich:Männlich-Ratio betrug in beiden Gruppen 1:1. Das mütterliche Alter und die Parität waren bei Schwangerschaften mit UCK im Vergleich zu den Kontrollen signifikant höher. Das mittlere Gestationsalter bei Entbindung betrug in der UCK-Gruppe 37,1 Schwangerschaftswochen. Bei der Perzentile des Geburtsgewichts gab es keinen Unterschied. Bei 47 Patienten (87 %) wurde die Geburt eingeleitet. Es gab keine Unterschiede in der Kaiserschnittrate oder bei den Apgar-Scores. Keines der Neugeborenen mit UCK musste beatmet werden. Keines litt unter Krampfanfällen, noch war eine Hirn-Bildgebung erforderlich. Bei den Schwangerschaften mit UCK gab es keine Fälle von fetalem oder neonatalem Tod.

Schlussfolgerung Es gibt eine hohe Detektionsrate von UCK bei der gezielten Untersuchung der Nabelschnur, die bei der anatomischen Level-II-Untersuchung durchgeführt wird. Eine sorgfältige Betreuung der Schwangerschaft und eine frühe Entbindung können zu einem hervorragenden geburtshilflichen Outcome führen.

Key words

true knot - induction of labor - cesarean section - umbilical cord


Publication History

Received: 02 November 2019

Accepted: 02 June 2020

Article published online:
16 July 2020

© 2020. Thieme. All rights reserved.

Georg Thieme Verlag KG
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Letter to this article:

Letter to the Editor Regarding the Article: “Antenatal Detection of True Knot in the Umbilical Cord – How Accurate Can We Be?”Ultraschall Med 2024; 45(01): 87-88
DOI: 10.1055/a-2072-0241

 

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