Oraekwe OI*, Egbo BI*, Kalu SA**, Nduka EC***.
(* Senior Registrar, ** Registrar, *** Head of Department. Department of Obstetrics and Gynaecology, Federal Medical Centre, Umuahia, Abia State, Nigeria.)
True umbilical cord knot is an uncommon form of umbilical cord accident. It carries a significant risk of adverse perinatal outcome. We present a case of a true umbilical knot in a 30 year old booked primigravida who had an emergency cesarean section on account of intrapartum fetal heart rate abnormality. Antenatal diagnosis of true knot remains a challenge especially in resource poor settings.
True umbilical cord knot is a rare but important cause of perinatal morbidity and mortality. It affects 0.3-2.1 % of all pregnancies,[1-3] with a perinatal mortality rate as high as 11%. True knots form when the fetus rotates in utero which occurs mostly between 9 and 28 weeks of gestation. Antenatal diagnosis of a true knot remains a challenge because there is no specific clinical feature attributed to the condition. Obstetric complications associated with this condition include cord compromise, fetal acidosis, low Apgar score at the first minute, higher risk of cesarean delivery and intrauterine fetal death. Despite the consequences, the prenatal management of this condition is yet to be determined.
A 30 year old primigravida, booked for antenatal care at Federal Medical Center, Umuahia at a gestational age (GA) of 12 weeks, on 20-12-2016. The index pregnancy was desired and spontaneously conceived. The booking weight was 64 kg; height was 1.64 m; blood pressure was 120/80 mm of Hg; hemoglobin concentration was 11.3 g/ dl, and urinalysis showed no abnormality.
Her hemoglobin genotype is AA and blood group is O rhesus D positive. The venereal disease research laboratory test was nonreactive and she tested negative to human immunodeficiency virus I and II. The index pregnancy remained unremarkable and ultrasonography done at 24 weeks GA revealed normal findings. Color Doppler ultrasonography was not done because it was not a routine antenatal investigation in the hospital. She was not a known hypertensive or a diabetic. Following the onset of labor pain on 26-06-2017 at a GA of 39 weeks, examination revealed a young lady in painful distress, afebrile, not pale and anicteric. There was no pedal edema. The pulse rate was 90 beats per minute (bpm), full volume and regular. The blood pressure was 120/80 mm of Hg. The heart sounds I and II were heard and there was no murmur. The respiratory rate was 24 cycles per minute and the breath sound was vesicular. The abdomen was enlarged and moved with respiration. The symphysio-fundal height was 38 cm. The lie was longitudinal and presentation was cephalic with the head 5/5 palpable per abdomen. The fetal heart rate was 164 bpm. Vaginal examination revealed cervical dilatation of 5 cm with the vertex at station 0-3. There was no cord prolapse. She was admitted into the labor ward where immediate intrauterine fetal resuscitation was commenced using intranasal oxygen at 6 liters per minute, intravenous normal saline at 30 drops per minute and she was placed on left lateral position. About an hour later the fetal heart rate however remained persistently elevated ranging from 168 to 175 bpm, necessitating an emergency cesarean section. Outcome was a male neonate which weighed 3.2 kg, with an Apgar score 9 and 10 in the first and fifth minute respectively. There was no retroplacental clot. The umbilical cord length was 70 cm with no gangrene. There was no gross fetal abnormality. The estimated blood loss was 400 ml. A true knot was found 40 cm from the placental insertion of the cord (Figure 1). The postoperative period was unremarkable and the woman was subsequently discharged on the 5th postoperative day.
Figure 1. The umbilical cord with a true knot.
The umbilical cord, which is an essential connection between the mother and the fetus, provides the baby with essential metabolites while transferring waste products back to the mother. Occasionally the cord is prone to a number of intrinsic or accidental disorders which may disrupt the cord morphology, decrease the blood flow in the cord and ultimately result in fetal compromise. There are about 30 conditions which can result in cord accidents and true umbilical knot is one such. Risk factors for this condition include excessively long cord, polyhydramnios, monoamniotic twin gestation, male fetuses, amniocentesis, obesity, gestational diabetes mellitus, advanced maternal age, small for gestational age fetus and multiparity.[5,7] The male baby was the only predisposing factor noted in our case.
In the antenatal period, the suspicion of a true knot can be entertained with difficulty by visualizing the ‘hanging noose sign’ on a gray-scale ultrasonography, however, the confirmation requires a color Doppler three-dimensional view.[1,4] This difficulty was shown by normal ultrasonographic findings noted in our case.
Most true knots are loose with no adverse pregnancy outcome except when they are tight, and this rarely occurs prior to the onset of labor. Our case had uneventful antenatal period, however, with onset of labor the true knot probably became tight manifesting as persistent fetal heart tachycardia. The good fetal outcome was due to immediate intrauterine resuscitation and timely abdominal delivery.
True umbilical knot is a rare but important cause of perinatal death. Even though its antenatal diagnosis has been advocated, this raises the question whether the women with the diagnosis should be allowed to labor or not. However for women with diagnosis of fetal heart rate abnormality in labor, true umbilical knot should be entertained as a possible cause and timely intervention may avert fetal demise.
- Kumar SS, Priya BA. True umbilical cord knot. Indian Journal of Health Sciences and Biomedical Research KLEU 2015; 8(2): 136-8.
- Kotingo EL, Allagoa DO. True umbilical cord knot, nochal cord and cord round body with favourable obstetric outcome in an unbooked elderly nullipara: a case report and literature review. International Journal for Research in Health Sciences and Nursing 2016; 2(2): 25-31.
- Airas U, Heinonen S. Clinical significance of true umbilical knots: a population-based analysis. Am J Perinatol. 2002;19(3):127-32.
- Bohîlțea RE, Turcan N, Cîrstoiu M. Prenatal ultrasound diagnosis and pregnancy outcome of umbilical cord knot-debate regarding ethical aspects of a series of cases. Journal of Medicine and Life 2016; 9(3): 297-301.
- Räisänen S, Georgiadis L, Harju M, Keski-Nisula L, Heinonen S. True umbilical cord knot and obstetric outcome. International Journal of Gynecology and Obstetrics 2013; 122(1): 18-21.
- Bangal VB, Shinde KK, Gavhane SP, Borawake SK , Chandaliya RM. Twisting of the umbilical cord causing intrauterine fetal death. International Journal of Biomedical and Advance Research IJBAR 2012; 3(8): 656-9.
- Khan M, Zahiruddin S, Iftikhar M. True knot of umbilical cord: case report and review of literat. J Pak Med Assoc 2016; 66(8): 1037-8.
- Szczepanik ME, Wittich AC. True knot of the umbilical cord: a report of 13 cases. Military Medicine 2007; 172(8): 892-4.
Oraekwe OI, Egbo BI, Kalu SA, Nduka EC. True Umbilical Knot With a Live Baby. JPGO 2017. Volume 4 No.9. Available from: http://www.jpgo.org/2017/09/true-umbilical-knot-with-live-baby.html