INTRODUCTION

Umbilical cord twisting with stricture is an often unrecognized cause of intrauterine fetal demise early in gestation. The rate of occurrence and cause of this condition are not known. We report a case of a 21-week gestation complicated by elevated Toxoplasma and parvovirus titers that ended because of umbilical cord stricture.

CASE REPORT

A 27-year-old G6P2 mother spontaneously aborted a 21-week infant weighing 260 g. She had two prior uncomplicated term spontaneous deliveries followed by three spontaneous abortions at 6, 6, and 4 weeks, respectively. The mother had received appropriate antenatal care. She had elevated titers for Toxoplasma and parvovirus, and an ultrasound showed an enlarged heart, excessive pericardial fluid, and an abnormal umbilical cord. She was sent for a consultation with a perinatologist and spontaneously aborted in the interim. An autopsy was performed. The significant postmortem findings were those of a macerated, hydropic fetus with a 61 cm umbilical cord (normal for age: 33 cm) (Figure 1a–c). The cord was dark red and fleshy with 57 twists that were tighter toward the fetal end (Figure 1c). The last 1 cm of cord at the fetal junction was thin, stenotic, and pale. Microscopically, most of the umbilical cord had dilated vessels and ample Wharton's jelly (Figure 1d). The umbilical cord at the level of the umbilicus showed an absence of Wharton's jelly and complete vessel occlusion at the stricture (Figure 1e). The placenta showed focal chorionic villi necrosis and thrombosis (Figure 1f). The heart was minimally enlarged, and no Toxoplasma or viral inclusions were identified in any fetal tissue.

Figure 1.

 

Full figure and legend (120K)

DISCUSSION

The cause of excessive umbilical cord twisting and stricture is unknown. It has no predilection for race, parity, gestational age, or fetal sex.¹ The mother often describes a period of increased fetal movement followed by complete cessation of fetal activity. The diagnosis of cord stricture is then assumed after death. The postmortem findings are, as in this case, a macerated fetus with a long umbilical cord with excessive twisting. Coarctation of the cord can occur anywhere along its length, but it occurs most commonly at the extreme fetal end.¹

A degree cord twisting is normal and may provide protection from compressive forces. Less spiraled cords are associated with an increased rate of complications.² Moderately twisted cords have been associated with a more favorable blood gas profile, less fetal entanglement, and better neonatal outcomes.³ With excessive twisting, the protective effects are lost, and the risk of fetal hypoxia abounds. A normal degree of twisting can be differentiated from excessive, pathologic twisting by counting the number of twists and dividing by the cord length in centimeters. Using this method, an umbilical cord coiling index was developed which demonstrates an average of 0.2 twists/cm of cord length.² Twisting that is significantly in excess of the average increases the risk of an adverse outcome. Histologically, fibrosis of the cord distinguishes true, established twisting and stricture from that which may have occurred during delivery or with post delivery handling.

Several explanations for cord twisting and stricture exist. Fetal activity is clearly a necessary component. Some suggest an accentuation of the natural narrowing of Wharton's jelly toward the fetus permits excessive movement, while others concede that fetal motion and twisting cause a focal diminution of Wharton's jelly.⁴ The sequence of events remains elusive, but it is generally accepted that cord twisting occurs early in gestation, while the fetus has room to move. Complications develop as the fetus grows and requires increased placental perfusion.

An accurate antenatal diagnosis of umbilical cord abnormalities presents a significant challenge. Umbilical cord ultrasonography and Doppler flow velocimetry have recently shown promise in the antenatal detection of umbilical cord morphologic abnormalities.^5,6 However, the utility of these techniques early in gestation, when the complications of cord twisting often occur, is questionable.⁷ A sudden change in fetal activity or physiologic signs warrants consideration of this uncommon condition. A careful assessment of the cord, particularly at the fetal end, should follow.

References

1. Tavares Fortuna JF, Lourdes Pratas M. Coarctation of the umbilical cord: a cause of intrauterine fetal death. Int J Gynaecol Obstet 1978;15(5):469–473. | PubMed |
2. Strong Jr. TH, Jarles DL, Vega JS, Feldman DB. The umbilical coiling index. Am J Obstet Gynecol 1994;170(1 Part 1):29–32. | PubMed |
3. Bender HG, Werner C, Karsten C. The influence of umbilical cord structure on the course of pregnancy and parturition (author's translation). Arch Gynakol 1978;225(4):347–362. | PubMed |
4. Benirschke K. Obstetrically important lesions of the umbilical cord. J Reprod Med 1994;39(4):262–272. | PubMed |
5. Sherer DM, Abulafia O, Anyaegbunam AM. Intra- and early postpartum ultrasonography: a review. Part I. Obstet Gynecol Surv 1998;53(2):107–116. | PubMed |
6. Sherer DM, Abulafia O, Anyaegbunam AM. Intra- and early postpartum ultrasonography: a review. Part II. Obstet Gynecol Surv 1998;53(3):181–190. | PubMed |
7. Marsal K. Intrauterine growth restriction. Curr Opin Obstet Gynecol 2002;14(2):127–135. | PubMed |