Rupture

It is not surprising that short cords may avulse from the placenta during descensus, particularly during a precipitous delivery. The cord may rupture completely or partially, and it may bleed or form hematomas. Bahary et al.

(1965) reported a severely anemic newborn whose marginally inserted short cord (24 cm) had ruptured during descensus. They believed that velamentous cord insertion was the most frequent antecedent of this complication. Rhen and Kinnunen (1962) lost a fetus with a 50-cm cord before labor due to a ruptured umbilical vein. It occurred spontaneously after tumultuous movements by the fetus. Foldes (1957) reported a stillbirth after rupture in which the normally long cord was wound tightly around the neck. These authors reviewed older literature of this rare event. Bleeding from the injured cord after amniocentesis has been recorded by ultrasonography (Romero et al., 1982); and the development of a cord hematoma following in utero transfusion, with bradycardia secondary to arterial spasm, was observed by Moise et al. (1987).

Such experiences and the question as to how much traction may be applied to the cord during delivery have stimulated systematic studies on the tensile strength of the umbilical cord (e. g., Crichton, 1973). Crichton tested 200 normal term umbilical cords without having their blood drained. He thus obtained a nearly normal distribution of breaking weights. Most cords ruptured when 12 pounds were applied, the extremes being 4 and 24 pounds. There was no correlation with fetal weight, length of cord, or placental weight. Although the cord ruptured most often (22.5%) at the site of its placental attachment, rupture could occur anywhere (Siddall, 1925). It must be said, however, that spontaneous complete rupture is an uncommon event; most ruptures are partial and cause local hematomas or hemorrhage. Leinzinger (1972) reported such a case in association with hydramnios and reviewed the relevant literature, but the case reported by Golden (1973) must not be cited as one of umbilical cord rupture. In his patient the cord separated when traction was applied to it after the child was delivered; the hematoma was at the site of detachment, and there was an adjacent IUD (Lippe’s loop). The photograph he supplied suggests that the cord was either marginal or in a velamentous insertion, a finding that is frequently made when lUDs remain during pregnancy. The IUD was certainly not within the amnionic sac and had nothing directly to do with the traumatic postnatal cord separation. More likely, the cord ruptured through velamentous vessels.

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