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The claims that marginal and velamentous insertion of the cord are associated with a high incidence of abortion, low birth weight, premature delivery, fetal malformation, fetal hypoxia and intrauterine fetal death have been investigated. A study of 1000 cases has failed to demonstrate any such association.

We report two cases in which the umbilical cords of fetuses were large on prenatal ultrasound scans. The pregnancies terminated uneventfully, however, and the babies were healthy at birth and on follow-up visits. We discuss the various etiologies of a large umbilical cord and conclude that, although a large cord may suggest the presence of an underlying abnormality, in some instances it may represent a normal finding.

We examined the gross and microscopic anatomy of placental tissues and umbilical cords from six species representing the three living families of the Suina. These species included, of the Suidae, the wart hog (Phacochoerus aethiopicus), the giant forest hog (Hylochoerus meinertzhageni), the domestic pig (Sus scrofa), and the banded pig of Malaysia (Sus scrofa vittatus); of the Tayassuidae, the white-lipped peccary (Tayassu pecari); of the Hippopotamidae, the hippopotamus (Hippopotamus amphibius) and the pigmy hippopotamus (Choeropsis liberiensis). All these species have a diffuse epitheliochorial placenta. The chorion is folded, and has on its surface rows of shallow ripples or villi, interrupted by round, oval or irregularly shaped areolae. Placental capillaries indent the epithelial layer covering the tops and sides of the interareolar villi, but not the columnar cell layer lying in the troughs between these villi or covering the areolae. Cuboidal cells cover the crests of the villi in the Suidae and Hippopotamidae, whereas in the Tayassuidae the epithelium is syncytial in appearance. The similarities in placental structure between the six species are more apparent than the differences. Suidae and Tayassuidae have smooth umbilical cords containing two arteries and one vein; those of the Hippopotamidae are pustule-encrusted and contain two arteries and two veins.

A brief description is given of the morphology of the umbilical cord and some variations encountered. In 95% of normal Thoroughbred foals the cord measures less than 84 cm. Factors which govern cord length are not known. Seven pathological conditions involving the umbilical cord are described. Increased length is the most common abnormality and predisposes to three potentially lethal conditions, strangulation of the cord around the fetus, excessive torsion, and allantochorionic necrosis at the cervical pole.

The helical structure of the human umbilical cord has been studied on 528 full-term cords from normal deliveries, 18 cords from aborted and developmentally normal fetuses with a CR length of 1.2-19.5 cm, 10 cords from monozygotic twins. In order to resolve the discrepancy in the nomenclature of the twist direction, a method has been suggested which takes into account the direction to which the fetus must have rotated to produce the twist. The incidence of the right helical pattern was 64.58%, of the left helical pattern 15.15%, and of the mixed patterns 17.43%; the twists were indeterminate in 1.89% and absent in 0.95% of the cords. Details of the mixed patterns are listed. The number of the uniform right twists ranged from 1 to 29 (7.5) and that of the left twists from 1 to 19 (6.7). There exists an exponential relation between the number of the twists and the ratio between length and thickness of the cords. The twists begin to appear during the early part of the 8th week, and their final number is possibly attained soon after the 9th week of development. In view of the absence of concordance in monozygotic twins, the helical nature of the cord is possibly controlled by factors which may be partly genetic and partly environmental.

In 429 placentae, measurements were made of weight, diameter, shape, eccentricity of the cord and weight and length of the cord, and the results were compared with Apgar score of the infant at birth and its standardized birth weight. There was no evidence that cord eccentricity, placental shape or "thickness", or the dimensions of the cord had any significant relation to the growth of the fetus or its condition at birth. The value of routine recording of crude measurements and qualitative assessments of the placenta in case notes is questioned.

Knowledge of the embryonic developments of the umbilicus and its contents assists the physician in correctly assessing the various anomalies found in this area. Although some will require specialized facilities and care, the majority of these anomalies can be corrected by simple operative means.

Abdominal and obstetric applications of a dynamically focused phased array real time ultrasonic system are described. This work was performed utilising both the Thaumascan (two-dimensional, high resolution, actual time, ultrasound, multi-element array scanner) and the first commercial unit based on this system, the Grumman RT-400. Examples of normal and pathological anatomy are presented from over 300 examinations performed to date, including a series of 28 abdominal aortic aneurysms studied with the RT-400. Following electronic alterations in the Thaumascan with resultant improvement in the grey scale, prospective analyses in 86 obstetric and 23 abdominal examinations were undertaken. These studies indicate that fetal, intra-uterine, and abdominal structures can be rapidly and consistently imaged. The value of real time ultrasonic scanning in obstetric and abdominal examinations is illustrated. The principles of dynamically focused phased arrays are described, and the merits and limitations of these systems are discussed.

To study effect of amniotic fluid volume on umbilical cord length, 939 pregnant women at 24-41 weeks of gestation, including 10 twin cases, 51 preterm premature rupture of the membranes (PROM) and 70 premature delivery cases, were examined for their amniotic fluid volume within a week of delivery by the ultrasound procedure and these 949 newborns were also examined for umbilical cord length and incidence of fetal distress. In the polyhydramnios group (pocket size of more than 8 cm), 8 of 20 infants (40%) had longer cords and 6 infants (30%) had shorter cords, while only one of 49 infants (2%) with oligohydramnios (pocket size of less than 2 cm) had a longer cord and 36 infants (73.5%) had shorter cords than the mean cord length (+/- SD) of the normal group. The 20 twins had significantly shorter cords than those of the normal group (P less than 0.05) and the polyhydramnios group (P less than 0.01). The PROM group showed significantly higher incidence of oligohydramnios (P less than 0.05) and fetal distress (P less than 0.01), which suggests that intrauterine space availability is important for assuring fetal well-being.

Of 211 consecutive thoroughbred foalings, 145 satisfied a set of criteria for normal parturition and foal viability. The fetal membranes from these and from 10 pony foalings have been systematically examined morphologically and quantitatively and the findings compared to those of other authors. Five sites on the allantochorion were consistently devoid of villi. Expulsion usually occurred with the non-villous side outermost. In 24 per cent of allantochorions the non-pregant horn was of equal length or longer than the pregnant horn. These placentae tended to be shed with the villous side outermost. All membranes contained a hippomane in the allantoic cavity. Remnants of the yolk sac placenta and extra-embryonic coelom were always present. Large vestigeal yolk sacs have previously been confused with anomalous twins. In most cases the endometrial cup sites were site recognisable, usually arranged around the umbilical cord attachment. This attachment was found on the dorsal aspect of the uterine cavity either at the junction of the horns or within the pregnant hor; rarely, it was in the non-pregnant horn. A degree of twistng of the umbilical cord is normal. In 6.2 per cent of cords small urachal dilatations were noted, resulting from flight stenosis of the urachal luman at the site of a twist. Ninety-five per cent of cords measured between 36 and 83 cm.

The importance of clinical follow-up of the growth in size of the uterus in the screening of intrauterine underdevelopment of the fetus and also other ovulatory anomalies has been stressed by the authors, and the acceptable standards for uterine heighth and umbilical circumference at the various stages of pregnancy have been assessed. Reference curves establishing the limits that correspond to 10th and 90th percentiles have been determined. An individual diagram that would permit to visualize successive measurements in any pregnant woman has been proposed. The authors have recommanded the use of an index of uterine development the abnormal values of which should be included in the evaluation of risk.