Mostyn P. Embrey

THE UNFAVOURABLE CERVIX AND INDUCTION OF LABOUR USING A CERVICAL BALLOON

WITH extension of the indications for operation, mostly on the grounds of suspected placental insufficiency, the artificial induction of labour plays an ever increasing role in obstetric practice. Unfortunately it is not invariably free of hazard, nor is it always successful (Barnes, 1965). Success is governed in particular by the state of the cervix (Garrett, 1960). When the cervix is well effaced and more than two fingers dilated, simple rupture of the membranes is nearly always satisfactory and rapid in initiating labour. But if the cervix is long, tight and undilated labour may be long delayed if it follows at all. The “failed surgical induction” is an all too frequent source of worry to the obstetrician even when oxytocin infusions supplement the procedure. As the attendant risks of foetal anoxia and intrauterine infection increase with delay he may feel that he has only exchanged one set of difficulties for another. Because of the risk of failure of induction of labour many obstetricians when confronted with a tightly closed cervix prefer to delay rupture of the membranes. Although it is less frequently used than it was at one time, induction of labour by the introduction of an oesophageal bougie or stomach tube, or by a large balloon, is still preferred by a few obstetricians when the cervix is unfavourable, especially in premature cases. Some content themselves with digital separation of the membranes, while others (Faris and Kahlenberg, 1954; Lennon, 1957; Eastmar,, 1960) recommend that time should be taken in attempts to “ripen” the cervix with oxytocin infusions. We have not been altogether satisfied with any of these methods. Simple stripping of the membranes is often ineffective. Induction of labour by bougie or large balloon of the Queen Charlotte’s Hospital type is apt to be slow and may be complicated by displacement of the presenting part or prolapse of the umbilical cord. The efficacy of the oxytocin infusion in ripening the cervix is still a matter of controversy. At the best, it is a time-consuming method and makes big demands on staff and patient alike. On the other hand, we have been impressed by the efficacy of rupture of the membranes when the cervix is ripe and we have therefore explored other methods of bringing about effacement and commencing dilatation of the cervix. The following simple method has given promising results.

THE EFFECT OF PROSTAGLANDINS ON THE HUMAN PREGNANT UTERUS

Observations were made in 15 patients in late pregnancy (36-42 weeks) and in 5 in early pregnancy in order to study the effects of intravenous infusion of pure prostaglandins on the mobility of the human pregnant uterus. Uterine contractibility was recorded by means of the Oxford Tocograph. Using both the E prostaglandins and those of the F series, stimulation of myometrial contractility was observed. The oxytocic properties of the E prostaglandins were particularly marked and reliable. In late pregnancy, and at term, the response was characterized by an increase in both the frequency and amplitude of contractions, without -- in the dosage used -- any appreciable increase in tone. Hypertonus was a feature of the response during the early months of pregnancy. Slow in action, the induced level of uterine activity tended to persist or recur for long after the infusion was discontinued and, particularly in the case of prostaglandin E2, was often followed by the successful induction of labor. On the basis of this study, it appears that the effect of prostaglandins in bringing about termination of pregnancy may be indirect.

THE EFFECT OF PROSTAGLANDINS ON HUMAN PREGNANT MYOMETRIUM IN VITRO

A study was undertaken to determine the effects of PGs (prostaglandins) F1alpha F2alpha E1 and E2. A total of 54 muscle strips of the myometrium from 29 uteri of women undergoing cesarean section at or near term were used in the study. On upper myometrial strips PGF1alpha in the 50-100 ng./ml. range produced mild stimulation and PGF2alpha in the 50-100 ng./ml. range produced strong and consistent contractions. Effects of the F prostaglandins were more variable on lower segment myometrial strips. Effects of PGE2 in the 80-100 ng./ml. range were more variable. This substance produced strong consistent contractions of upper segment muscle. Other PGE substances produced moderate spasmogenic responses to no response. These findings contrast with previously reported behavior of PGs on nonpregnant myometrium tissue whose contractility is usally stimulated by PGFs and inhibited by PGEs. Selectivity of action was noted in that the lower segment was relatively inactive in comparison with upper segment muscles.

A COMPARISON OF THE OXYTOCIC EFFECTS OF SYNTHETIC VASOPRESSIN AND OXYTOCIN

WHEN, many years ago, the two principles of the posterior lobe of the pituitary gland were separated, the terms “vasopressin” and “oxytocin” were introduced to indicate the essential action of each. It therefore came as a surprise to find that in one respect the names were misleading, for vasopressin had, on the intact human non-pregnant and early pregnant uterus, an oxytocic action greater than that of oxytocin (Moir, 1934, 1944). Other more recent workers, for example Schild et al. (1951), have corroborated this finding. Although the evidence in favour of this paradoxical effect seemed convincing, there has been, hitherto, a lingering suspicion that the observed actions might be explained by an incomplete separation of the two pituitary fractions. With the advent of pure synthetic preparations of both posterior lobe hormones we have now put this possibility to the test and compared the effects of synthetic oxytocin and synthetic arginine-vasopressin on the human non-pregnant and pregnant uterus. Records of uterine contractility were obtained by the conventional means of inserting a small rubber bag in the uterus and recording the variations of intrauterine pressure on a kymograph. In early pregnancy, the observations were made when a therapeutic abortion was deemed necessary, and the recordings obtained either immediately before, or immediately after, the operation. Before going further it is necessary to digress in order to explain an elementary matter with regard to the standardization of the two principles. In brief, an oxytocic unit relates to a specific effect, under standard conditions, of the test substance on the isolated rat uterus; a vasopressor unit relates to a specific effect, under stated conditions, on the blood pressure of the rat. There is no relationship between the two different units; hence it would be meaningless to claim that one substance has less or more action on the uterus than the other, when the measurement of dosage in one case is oxytocic and in the other vasopressor. One can, however, compare the two substances with regard to their uterine action when the dose chosen is one which would be reasonably used in clinical work and which would fall short of producing undesirable side effects. It is in this sense that the two products are now compared.

Premature rupture of the membranes.

PREMATURE rupture of the membranes is defined for the present purpose as spontaneous rupture occurring before the recognizable onset of labour, and this communication deals with 1,052 patients in whom this complication was observed in the Obstetric Department of Southmead Hospital, Bristol, in the two years 1949-50. The diagnosis, in each case, depended on clinical evidence, without recourse to chemical tests for the escape of liquor a d . A small number of questionable cases had to be eliminated, but otherwise there was no selection of clinical material.

THE EFFECTS OF INTRAVENOUS OXYTOCIN ON UTERINE CONTRACTILITY

The recording unit of the tocograph is calibrated (before each study) so that in the resulting record the intensity of each contraction

A NEW MULTICHANNEL EXTERNAL TOCOGRAPH

11 can be measured (in mm. Hg) by its elevation above the base line. The base line represents the uterine tone and a minute scale denotes the INTENSITY ur ACTIVITY THE continuous intravenous infusion of oxytocin, recommended first by Theobald and associates (1 948) and soon by Hellman ( 1949) is nowadays established in obstetric practice as a means of inducing labour or augmenting the contractions of inert labour. With the passage of time, the technique has become more or less standardized, yet there are many variations of detail (Theobald, 1959; Ryan, 1960) and, even now, little precise guidance regarding the optimum dosage, the uterine response to it and, i n particular, any relationship between the response and success in clinical events. The following investigation was undertaken as the first part of a study designed to supply such in for mation.

VULVAL CARCINOMA COMPLICATING CONDYLOMATA ACUMINATA

A FUNDAMENTAL difFiculty in the elucidation of the problems of abnormal uterine action is that of satisfactorily recording and assessing uterine motility, and it is natural that many experimental investigations have been directed to this end. The earlier attempts at obtaining a graphic record of uterine contractions have been reviewed elsewhere (Embrey, 1940; Murphy, 1947) and need not be detailed, but briefly such recording may be by internal or external means. Internal Tocography. This has mostly been eEected by the introduction of a hydrostatic balloon or metreurynter between the membranes and the uterine wall connected with a pressure recording apparatus. The method has been much used and to good purpose by Bourne and Burn (1927) and Moir (1932, 1935), whose works in this connexion are well known. It enables changes in uterine pressure to be accurately recorded and is applicable not only in labour but it can be adapted for use in the puerperium. More recently changes in intra-uterine pressure have been recorded by directly tapping the amniotic sac-which is itself the intra-uterine balloon-and connecting it to a manometer. Alvarez and Caldeyro (1950) achieved this by abdominal paracentesis, while Williams and Stallworthy (1952) punctured the amniotic sac per vaginam. A disadvantage of these methods is that they can only be employed during or immediately preceding labour. External Tocography. The recording of uterine contractility by an apparatus applied to the maternal abdomen is of course indirect and cannot quantitatively measure uterine pressure, but it has the advantage that there is no trespass of the genital canal and so avoids the inherent objection of internal recording. External tocographs have been of several types. In Dodek’s apparatus (1932) movements of a plunger applied to the abdomen were transmitted to a recording tambour by a pneumatic system. Moir (1935) used a modification of this apparatus in which the method of recording was hydraulic, and similar apparatus has been employed by the writer. In recent years mechanical and mechanoelectrical recorders have received more attention. Murphy’s (1947) publications have popularized the Lorand tocograph. This is a mechanical clockwork instrument, in which the actuating plunger projects a fixed distance from its base. Using it Murphy claims to estimate uterine tone as well as contractions and distinguishes hypertonic and hypotonic types of uterine activity. The multichannel strain gauge tokodynamometer of Reynolds, Heard, Bruns, and Hellmann (1948), and Reynolds, Hellmanii and Bruiis (1948) employs a mechano-electrical device. A non-adjustable plunger actuates a strain gauge and by suitable electronic magnification produces a graphic record. Three strain gauges enable the activity of different parts of the uterus to be studied simultaneously. The apparatus is necessarily both complicated and costly; but it has been used by Reynolds with good effect, and from this work he has derived his concept of coordinated uterine activity with a “gradient of activity” and “fundal dominance” The recording of uterine contractions by measuring changes in electrical potential (Dill and

A SIMPLIFIED INTERNAL TOCOGRAPH

THERE are surprisingly few recorded instances of carcinoma of the vulva occurring as a result of malignant metaplasia in condylomata acuminata. A few references to the subject are made by Gernian authors. Among them Treite (1941) quotes the views of Kehrer (1929) when dealing briefly with the subject of malignant metaplasia in benign papillomata; he suggests that persistent mechanical irritation and concomitant vulvitis are predisposing factors in the malignant degeneration of benign papillomata and that malignant metaplasia occurs less frequently with condylomata acuminata than with other papillomata because of the lower age incidence. Dcscribing a recent case, Charlewood and Shippel (1953) suggest that the condition may be more frequent in negroes than whites. The following is a brief record of a very large carcinoma of the vulva arising in a pre-existing mass of condylomata acumina in a young white woman. CASE HISTORY A 33-year old, para-2, very obese (18 stone) and of low intelligence, presented in October, 1957 complaining of a swelling of the vulva. She stated that a mass of warts had been present at the vulva for 11 years, that it had been getting bigger for 3 years, while there had been some bloodstained discharge for 3 months. The menses were regular and normal.

HAEMANGIOPERICYTOMA OF THE UTERUS AS A CAUSE OF HAEMOPERITONEUM

IN the experiments to be detailed elsewhere in this Journal two different methods of tocography were employed. In a few cases, early in the puerperium, the external tocograph previously described (Embrey, 1955) was used. Mostly, however, the records were obtained in the second week of the puerperium by an internal method, using a recently developed modification of the original recorder. The instrument, as now modified, provides the facility of both internal and external recording of uterine motility. METHOD The principle of the internal method employed is to record graphically the pressure changes in a small intra-uterine balloon. This means of recording was first used as long ago as 1872 by Schatz, who introduced a large colpeurynter into the parturient uterus outside the membranes and measured the pressure with a mercury manometer. The method was later used to good purpose by Bourne and Burn (1927), who introduced a small rubber balloon (8 ml.) between the membranes and the uterine wall, and subsequently was modified by Moir (1932) for recording the contractions of the puerperal uterus. While not differing from these wellknown and well-proven methods in principle, the tocograph to be described uses a simplified system of recording which, without any sacrifice of accuracy, obviates some of the inconveniences usually associated with internal tocography. The intra-uterine balloon of 8 ml. capacity is connected by polyvinylchloride tubing to a