Size of trials for evaluation of antenatal tests of fetal wellbeing in high risk pregnancy

A retrospective study of maternity records from 1977-1985 (38,000 deliveries) was conducted to determine the number of stillbirths that might have been prevented by a new method of antenatal assessment. During this period there were 240 stillbirths, 154 of which involved a normally formed fetus who died prior to the onset of labour. After a review of the literature, a set of risk factors were selected relevant to stillbirth. Such factors were found in 60% of the study group, compared with 38% of control patients. Seventy-five of the normally formed 'antepartum stillbirths' occurred in the high-risk group after 31 weeks gestation, so that a perfect method of prediction and treatment, applied from 31 weeks onwards, would potentially have prevented half of the 154 deaths in this study. Since intensive monitoring and the subsequent intervention cannot attain such perfection, an assessment was made, using realistic sensitivity and specificity values and other reasonable assumptions, to show that approximately one third of antepartum stillbirths might have been prevented by a new method for monitoring of all high-risk pregnancies. A sensitivity analysis was used to test this conclusion over a range of possible test performance values. The implications of these findings for clinical trials and cost-utility analysis are discussed.

Simulation of cervical changes in labour: reproducibility of expert assessment

A carefully designed set of simulators showing cervical effacement and dilatation was used to assess the error within and between observers in a group of 36 midwives and 24 obstetricians. No observer was correct in every case. There was no significant difference between the obstetricians and the midwives in assessment of effacement or overall assessment of dilatation. However, midwives were significantly more likely than obstetricians to assess dilatation inaccurately by more than 1 cm. Inaccuracy was greatest in the simulators 5-7 cm dilated. These findings have implications for labour management and teaching.

Umbilical artery Doppler velocimetry as a predictor of fetal hypoxia and acidosis at birth

We studied the relationship between preoperative umbilical artery Doppler waveforms and umbilical vein pO2 and pH at elective cesarean section. An absence of end-diastolic velocities had a strong statistical association with hypoxia and acidosis, and was an accurate clinical test for hypoxia (sensitivity 78%, specificity 98%, positive predictive value 88%, and negative predictive value 98%) and acidosis (sensitivity 90%, specificity 92%, positive predictive value 53%, and negative predictive value 100%). It was also a clinically sensitive indicator of perinatal morbidity and mortality. Most fetuses with no end-diastolic velocities were growth-retarded, but the reverse was not true. The absence of end-diastolic velocities also divided both mature and immature fetuses into high- and low-risk groups for hypoxia and acidosis. In the presence of end-diastolic velocities, only very high S/D ratios (above 4.5) have any association with hypoxia. As a noninvasive test of fetal umbilical vein pO2 and pH, umbilical artery Doppler performs well.

The action of squatting in the early postnatal period marginally increases pelvic dimensions

X-ray pelvimetry was performed on 43 women in the squatting and erect positions within 1 week of delivery. The act of squatting increased the transverse and antero-posterior pelvic dimensions by 1%. The theoretical mechanisms by which posture may affect dimensions are discussed.

A new surgical technique to treat refractory labial fusion in the elderly

An elderly woman with refractory labial fusion was treated by labial separation. The subsequent raw area was covered by a rotational skin flap from the thigh. The flap was deroofed of epithelium proximally and tunnelled subcutaneously. The distal portion emerged to cover the raw clitoral area and this successfully prevented contraction and scarring.

Surgical abortion at twenty weeks: is morality determined solely by the outcome?

A strong body of opinion contends that late terminations of pregnancy are better carried out by surgical methods. We show that the suggested advantages of greater safety and patient acceptance are based on out-of-date or inaccurate (biased) data. The advantages of medical methods are, however, equally unproven. However, we argue that the adverse emotional and symbolic effects of late surgical termination have moral force. We therefore contend that in the absence of strong patient preference, medical termination is the preferable method; and will remain of that opinion unless clear demonstration of the greater safety of surgical methods can be made at some future date.

Audit of medical response to antenatal booking history

A retrospective review of 600 obstetric case-notes, covering the years 1978 to 1984, was performed independently by two assessors. The medical response to 22 risk factors, recorded at booking by the midwife, was assessed. The medical staff recognized 69% of the risk factors recorded at booking and responded appropriately to 82% of these. The standard of care improved over the period studied. The accuracy of our conclusions was greatly enhanced by carrying out each assessment in duplicate with arbitration by a third assessor when necessary, and it is proposed that all audits of medical practice should themselves be audited in this way.

Post-surgical pyoderma gangrenosum of the vaginal vault associated with ulcerative colitis and Behçet's disease; a case report

A case is described in which a patient with ulcerative colitis developed chronic vaginal ulceration around the incision lines after cone biopsy. The ulcers persisted at the vaginal vault after abdominal hysterectomy and removal of a cuff of vagina. Non-specific histological features compatible with pyoderma gangrenosum were found on biopsy. The auto-immune nature of this chronic ulcer is further supported by its rapid response to steroid therapy and the subsequent development of Behçet's syndrome.

A prospective study of the incidence and significance of fetal choroid plexus cysts

Cysts of the choroid plexus of the lateral ventricle can be detected in the fetus during routine scanning at 16-18 weeks' gestation with an approximate incident of one in every 120 pregnancies. It is likely that in a high percentage of cases cysts are bilateral and that their recent discovery is mainly due to improvements in imaging technology. Although the great majority of cases resolve and do not result in any morbidity, five cases of trisomy 18 and one case of trisomy 21 associated with fetal choroid plexus cysts have been reported. In this prospective study, choroid plexus cysts were detected in 42 fetuses, resulting in 40 normal infants and 2 cases of trisomy 18. It is concluded that there may be a relationship between fetal choroid plexus cysts and trisomy 18. In order to obtain a more precise and accurate result, a multi-centre prospective study is being organized.

An experiment of squatting birth

Women throughout the ages have preferred to be delivered with their trunks vertical and most delivery positions illustrated in historical texts show birth in an upright posture with abducted thighs. A consumer attitude study in our hospital showed that patients have considerable interest in alternative birth positions. Squatting has been advocated to prevent caval compression, increase the diameter of the pelvic outlet and, perhaps with least justification, to enlist the force of gravity and thereby facilitate maternal expulsive effort. Despite the extensive literature advocating squatting birth, the suggested advantages of this method have not been examined in any formal, let alone unbiased study. We therefore conducted a randomised trial to examine the effect of squatting on the duration of second stage of labour, the duration of pushing, and several other variables.

The megacystis-microcolon-intestinal hypoperistalsis syndrome: a fatal autosomal recessive condition

We report the cases of two sibs with the megacystis-microcolon-intestinal hypoperistalsis syndrome. The parents are first cousins. These cases further support the view that this syndrome is inherited in an autosomal recessive fashion.

Evaluating new treatments and diagnostic technologies in obstetrics. Practical problems, ethics, and solutions

This article develops arguments for the use of decision theory, rather than intuition, to determine the size of trials. It is wrong to expect doctors to ignore personal preferences in favor of clinical experiments unless the trial is capable of showing differences in treatment effect that would influence clinical practice substantially. It follows from our analysis that if delta (the treatment effect that the trial is designed to detect) is sufficient to alter clinical practice, then the alpha and beta errors of a trial should be equal. This applies even if a new treatment is to be compared with conventional therapy or if a treatment with high "costs" is compared with a less invasive or more inexpensive method.

Is routine antenatal booking vaginal examination necessary for reasons other than cervical cytology if ultrasound examination is planned?

Sixteen ovarian cysts, including one borderline ovarian malignancy, and ten trichomonal vaginal discharges but no cases of cervical incompetence or ectopic pregnancy had been detected at booking vaginal examination in 11,622 consecutive antenatal case records abstracted retrospectively. In an attitude survey of pregnant women 77% believed that vaginal examination was reassuring, 55% found it unpleasant, and 18% thought it could cause miscarriage. This, and a review of the literature, suggests that routine vaginal examination if ultrasound is planned has few advantages beyond the taking of a cervical smear.

Should maternal alpha-fetoprotein estimation be carried out in centers where ultrasound screening is routine? A sensitivity analysis approach

We describe a case of small, open spina bifida that was detected on the basis of maternal serum alpha-fetoprotein levels but consistently missed on careful ultrasound examination. This prompted us to reexamine the policy (adopted by an increasing number of departments) of relying exclusively on ultrasound examination for the detection of spinal lesions. In this article we therefore analyze the number of additional cases of spina bifida that could be detected by offering maternal serum alpha-fetoprotein screening in addition to a routine ultrasound examination. Our calculations are made on the basis of published assessments of the performance of these tests and on the assumptions about test independence. We test our conclusions against a wide variety of test performance values in a detailed sensitivity analysis. The final decision to carry out maternal serum alpha-fetoprotein testing is a value judgment, but this decision should be based on realistic numeric estimates of the potential benefits and hazards of this procedure.

Use of a computer to take booking histories in a hospital antenatal clinic. Acceptability to midwives and patients and effects on the midwife-patient interaction

An interactive computer system was used by midwives to acquire a full patient history at the first antenatal visit. The clinical efficacy of the system had been previously established. The present evaluation examined the effects of computer use on the interview process and on midwife-patient communications, and its acceptability to midwives and patients. Data included video recordings of 32 conventional interviews and of 63 interviews in which the computer was used, each with associated questionnaires assessing patients' reactions. Midwives' views were obtained through a structured discussion session. Computer use had no effects on patients' reactions to the interview, and midwives were enthusiastic. Detailed analysis of the video recordings using established quantitative techniques did not reveal any negative psychologic effects that would preclude the use of nurse-patient interactive computers. However, midwives were inclined to give less information to patients, especially when they were new to the computer, and to use more closed questions and leading questions. The findings have important implications for the future use of similar computer systems. These are presented in the form of guidelines for future systems design and implementation.