August 2016, Volume 66, Issue 8

Case Reports

True knot of umbilical cord: Case report and review of literat

Momna Khan  ( Department of Obstetrics and Gynecology, Aga Khan Maternal and Child Care Centre, Hyderabad. )
Sana Zahiruddin  ( Department of Obstetrics and Gynecology, Aga Khan Maternal and Child Care Centre, Hyderabad. )
Maria Iftikhar  ( Department of Obstetrics and Gynecology, Aga Khan Maternal and Child Care Centre, Hyderabad. )

Abstract

True knot of umbilical cord (TKUC) is a rare abnormality. When it becomes tight, it may lead to the obstruction of the foetal circulation and intrauterine death (IUD). We present two cases of TKUC managed at The Aga Khan University Hospital with two extreme outcomes. A 22 years old primigravida was diagnosed with unexplained intrauterine foetal demise at 28th week gestation. She delivered vaginally after induction and tight TKUC was identified as a cause of IUD. The second patient delivered an alive healthy male baby vaginally who was found to have a lose TKUC.
Keywords: Umbilical cord, True knot, Intrauterine death.

Introduction
The incidence of TKUC is around 0.3-2% of all deliveries.1 Predisposing factors include long cord, polyhydramnios, small foetus, mono-amniotic twins, male foetuses, gestational diabetes mellitus, genetic amniocentesis and multiparty. Most knots are loose with no clinical significance, though there exists an association between cord knots and intrauterine death.2 True knot of umbilical cord is associated with four fold increase risk of intrauterine foetal death.3 A case of "hanging injury" from a tightened true knot of the umbilical cord which resulted in intrauterine foetal demise has been reported from Virgini.4 Similarly Sharma et al presented a case of a 20 years old primigravida who delivered a baby with true knot of umbilical cord.5 Author is presenting two cases of TKUC not diagnosed on antenatal ultrasound.

Case-1
A 22 years old primigravida came in the emergency room with 28 weeks pregnancy and absent foetal movements for one day. She had no comorbids and an uneventful pregnancy. Ultrasound showed (IUD) of 28 weeks gestation with adequate amount of liquor and no gross structural abnormality. All her laboratory investigations were within normal range. She delivered vaginally a dead male foetus of 1.5 kg with a tight TKUC (Figure-1)

Cord was gangrenous 40 cm long and placenta was normal. She did not come for a follow up after discharge.

Case-2
A 24 years old 2nd gravida was admitted at 38 weeks pregnancy with labour pains. Her last baby was delivered by caesarean section 18 months earlier. She had regular antenatal checkups and the antenatal period was uneventful. Her antenatal blood workup and ultrasound were within normal limits. She delivered an alive and healthy male baby of 3.4 kg with Apgar score of 7 and 9 in one and five minutes. There was no excess liquor or meconium staining and blood loss was minimal. The placenta appeared normal. The cord, however, had one knot that was loose (Figure-2)

The cord measured 68cm. This patient was followed two weeks after delivery and the baby was found in good health.

Discussion
The umbilical cord is called the foetal life line.6 Various abnormalities are observed in the morphology and pathology of the umbilical cord but knowledge of them is rather poor.4 A TKUC  may cause foetal hypoxaemia or even IUD.7 Umbilical cord true knots during the second trimester are a very rare cause of abortions7 though it is said that its presence during the third trimester and labour is not associated with increased perinatal morbidity and mortality.8
Some authors believe that 3D power sonography may be helpful in the diagnosis of the umbilical cord knots especially in the 3rd trimester.9 Ramon et al reported characteristics sonographic findings of this condition.10 Study done by Guzikowski et all to assess the role of 2D and 3D ultrasound for diagnosing true knot of the umbilical cord found it a useful modality.6

Conclusion
Although the incidence, predisposing factors and potential outcomes of true umbilical knots have all been reported, the prenatal diagnosis and clinical management of the condition have not yet been clearly determined. Three-dimensional and colour Doppler examination is very important to diagnose a true umbilical cord knot. Perfection of true umbilical cord knot diagnosis and then follow up sonographic imaging and close monitoring until the determination of foetal maturity, is the best way to achieve a good outcome.

Acknowledgement
We acknowledge the valuable input by Dr. Salma Khan for manuscript writing and revision.

References
1. Pinar H, Carpenter M. Placenta and umbilical cord abnormalities seen with stillbirth. Clin Obstet Gynecol. 2010; 53:656-72.
2. Chan JSY, Baergen RN. Gross umbilical cord complications are associated with placental lesions of circulatory stasis and fetal hypoxia. Pediatr Dev Pathol. 2012; 15:487-94.
3. Bosselmann S, Mielke G. Sonographic Assessment of the Umbilical Cord. Geburtshilfe Frauenheilkd. 2015; 75:808-18.
4. Szczepanik ME, Wittich AC. True knot of the umbilical cord: a report of 13cases. Mil Med. 2007; 172:892-4.
5. Sharma B. True Knot of the Umbilical Cord: A Case Report. Global JMed Res. 2013;13:32-4.
6. Guzikowski W, Kowalczyk D, Więcek J. Diagnosis of true umbilical cord knot. Arch medical sci AMS. 2014;10:91-5.
7. Srinivasan A, Graves L. Four true umbilical cord knots. J Obstet Gynaecol Can. 2006; 28:32-5.
8. Bakas P, Papadakis E, Hassiakos D, Liapis A. Second-trimester miscarriage and umbilical cord knot. Case report and review of the literature. Clin Exp Obstet Gynecol. 2013; 40:448-51.
9. Scioscia M, Fornalè M, Bruni F, Peretti D, Trivella G. Fourâ€dimensional and Doppler sonography in the diagnosis and surveillance of a true cord knot. J Clin Ultrasound. 2011; 39:157-9.
10.López Ramón Y Cajal C, Ocampo MartAnez R. Prenatal diagnosis of true knot of the umbilical cord. Ultra Obst & Gyn. 2004; 23:99-100.
 

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