If a mother's cervix is not well applied to the presenting part, her baby's cord can prolapse when her membranes rupture, especially if his head is high, or she has a transverse lie, a breech, a face presentation, or twins. The cord is said to be presenting when it lies below the presenting part, inside her intact membranes. Both prolapse and presentation can obstruct the circulation in it, and so endanger his life. Other presenting parts press less firmly on his cord than does his head, but don't let this delay you.
Fig. 19-6 TREATING PROLAPSE OF THE CORD BY FILLING THE BLADDER. A, the head pressing on the cord. B, the patient's bladder has been filled through a catheter, and the cord is now free. A full bladder also inhibits contractions of the uterus.
PROLAPSE AND PRESENTATION OF THE CORD PROLAPSE. ALWAYS do a vaginal examination immediately a mother's membranes rupture spontaneously, unless: (1) She is [lt]36 weeks and is not having contractions, and you are considering non-operative management. Or, (2) her baby's head is well down (not more than 2/5 above the brim).
If you find a prolapsed cord, DON'T take your hand out of her vagina!
Instead, push his head (or breech) off the cord. While you are holding his head, ask an assistant to insert a Foley catheter and fill her bladder with 500 ml of Ringer's lactate or saline. A full bladder will keep his head away from the cord and inhibit the contractions of her uterus.
Listen to his heart, to find out if he is still alive. It may still be beating, even if his cord is not (cord spasm). Assess his size, and try to exclude gross congenital abnormalities, particularly hydrocephalus.
Remove your fingers, and apply a pad to her perineum, so that the cord remains in her vagina. Turn her on to her side with the foot of her bed raised. Or put her into the knee-elbow position (19-2). Set up an isoprenaline infusion (M 19.6). Put her on a trolley, and take her to the theatre for section as soon as possible. Don't pass a stomach tube; instead give her an antacid. Don't empty her bladder until you are ready to incise her parietal peritoneum.
Always section her unless: (1) She is fully dilated and the head is only 2/5 or less above the brim (unusual). If so, apply forceps (if you are experienced with them because they are quicker), or a vacuum extractor. (2) Prolapse of the cord complicates the delivery of a second twin with a cephalic presentation. If there is no CPD, you can usually apply a vacuum extractor, or do a breech extraction preceded by internal version if necessary.
PRESENTATION OF THE CORD. If you feel the cord vaginally when she has intact membranes, observe carefully for the fetal heart changes which indicate cord compression (M 18.56): (1) Put her into the head-down or knee-chest position. Nurse her with the foot of her bed raised for 24 hours. This will nearly always allow it to rise above his head. Or, (2) before 37 weeks, try external version. Turning him may draw the cord from under the presenting part. Or,(3) section her, unless he is dead or too small to survive.
Fig. 19-7 HOW TWINS PRESENT. In 40% of cases both twins are cephalic. In 21% the second twin is a breech. In 14% the first twin is a breech. In 10% of cases both twins are breeches. In all remaining cases one or other twin, or occasionally both, are transverse.