Dynamic ultrasonographic imaging of the third stage of labor: new perspectives into third-stage mechanisms.

Objective: Dynamic ultrasonographic imaging of the third stage of labor was performed to document ultrasonographic findings and to present new perspectives into third-stage mechanisms.

Study Design: Twenty-five normal deliveries and five with prolonged third-stage labor were studied.

Results: Normal third-stage labor could be divided into four phases: (1) latent phase, characterized by thick, placenta-free wall and thin, placenta-site wall; (2) contraction phase, with thickening of placenta-site wall (from < 1 cm to > 2 cm); (3) detachment phase, in which the placenta completes its separation and detaches; and (4) expulsion phase, with a sliding movement of the placenta.

Indomethacin and amniocentesis-induced changes in fetal flow velocity waveforms.

The effect of genetic amniocentesis on flow velocity waveforms in the fetal aorta and the umbilical artery, and fetal heart rate and their correlation with uterine contractions was examined in 75 pregnant women who underwent this procedure. Forty-three were untreated and 32 were pretreated with indomethacin. Median maternal age was 36 years and median gestational age was 18 weeks.

Extremely large number of twists of the umbilical cord causing torsion and intrauterine fetal death.

Extremely large number of twists of the umbilical cord causing torsion of the entire length of the umbilical cord was found in two cases of intrauterine fetal death. It was twisted in one case 35 times and in the other 20 times. No additional pathology, such as stricture or abnormality of the Wharton's jelly, was found.