The second stage of labour: durational dilemmas.

The optimal management of prolonged second stage of labour remains a confused area of thought and action. This confusion is particularly evident when epidural analgesia is also being used. A review of the literature indicates that prolonged duration of the second stage, i.e. from full dilation of the cervix until delivery, with or without epidural analgesia, has little adverse effect on perinatal outcome. More attention should be paid to the expulsive phase of the second stage and greater efforts made to reduce unnecessary interventions.

Monitoring epidural analgesia in the parturient.

Appropriate monitoring during obstetric epidural analgesia consists of: 1. Indirect BP and pulse monitoring before epidural insertion, frequently after every dose, and intermittently thereafter. 2. The aspiration test before all injections. 3. Frequent clinical monitoring for signs of intravascular injection during administration of small intermittent doses (not more than 3-5 ml at a time). 4. Frequent clinical monitoring for sympathetic, sensory and motor signs indicating upward extension of the block. 5. Frequent monitoring of the fetal heart rate (FHR) and other signs of fetal welfare. In many instances continuous tocogram with fetal heart rate (CTG) monitoring is useful. We do not believe CTG use is mandatory for epidural analgesia in the uncomplicated pregnancy, but we do advocate that it (and other appropriate fetal monitoring techniques) be used when risk factors or complications, either fetal or maternal, are present or suspected. The anaesthetist should be familiar with fetal monitoring techniques, their use and interpretation. He or she should be prepared to recommend their use when it is considered appropriate to do so.

Severe preeclampsia: is vasodilation therapy with hydralazine dangerous for the preterm fetus?

Increasing experimental and clinical evidence points to a subset of severe preeclamptic women who are hypovalemic with a low cardiac index and a high systemic vascular resistance, and in whom vasodilatory therapy may cause precipitate falls in maternal perfusion pressure, unless anticipated by prior correction of the hypovolemia. Since there is a paucity of adequately controlled clinical trials with appropriate definitions of hypotension or perinatal outcome, the consequences of such episodes for the preterm fetus are unknown. Epidemiologic evidence, using a logistic regression analysis model, is reviewed, which points to an association between a hypotensive episode following a commonly used drug, hydralazine, and a worse perinatal outcome in a study of severely hypertensive women delivered less than 32 weeks. An estimate of this risk, using the odds ratio, is 5.97 (95% confidence interval 1.84 to 19.35).

Outcome of pregnancies complicated by severe hypertension and delivered before 34 weeks; stepwise logistic regression analysis of prognostic factors.

The outcome is described for 106 patients with severe hypertension in pregnancy requiring delivery between 26 and 34 weeks. Management was with methyldopa, hydralazine when required and delivery by caesarean section when indicated. Most patients were delivered for cardiotocographic fetal distress or unstable maternal blood pressure. Eighty-five babies (80%) survived and were well at follow-up at 1 year; the perinatal mortality was 123/1000 total births. One patient had postpartum eclampsia, one had pulmonary oedema and one had transient renal failure, but all mothers left hospital well. Stepwise logistic regression analysis showed that the primary positive factor for survival of a healthy baby was gestational age, which was strongly correlated with birthweight. The need for caesarean section as an emergency, hypotension after parenteral hydralazine, intrauterine growth retardation, and severe proteinuria were adverse factors. Intraventricular haemorrhage had a major adverse effect on neonatal survival; it was predisposed to by prolonged maternal hypertension and by low gestational age.

Haemorheological consequences of oestrogen and progestogen therapy.

A clinical investigation was undertaken of the haemorheological effects of short-term administration of synthetic sex hormones. In a randomised controlled investigative trial, groups of 20 women taking ethynyloestradiol, norethisterone, combined norgestrel and ethynyloestradiol or no therapy had their blood viscosity and its major determinants measured before and after 3 months of treatment. Oestrogens and progestogens, singly or in combination, were found to cause a rise in blood viscosity. Oestrogens did so by raising haematocrit and plasma fibrinogen, parameters that are similarly raised in other conditions such as pregnancy and following surgery when venous thromboembolism is common. The synthetic progestogen, on the other hand, raised the blood viscosity by increasing the haematocrit and decreasing erythrocyte deformability, parameters that are similarly altered in occlusive arterial disease. The combined preparation raised blood viscosity by altering all three parameters. These observations indicate the pathways whereby various synthetic oestrogens and progestogens in oral contraceptives or replacement therapy may be associated with different types of cardiovascular pathology.

Early seizures indicate quality of perinatal care.

An analysis of antepartum, intrapartum, and postpartum variables was performed in a retrospective controlled study of 34 normally formed term infants who had perinatal asphyxia and subsequently displayed generalised seizures within 48 hours of birth. The aim was to identify any association, firstly between these variables and seizures, and secondly between these variables and subsequent morbidity and mortality among the seizure group. Maternal age greater than 35 years, duration of labour, meconium stained liquor, abnormal intrapartum fetal heart rate trace, and operative delivery were associated with seizures. A low Apgar score at five minutes, and intermittent positive pressure ventilation at birth of longer than 10 minutes were associated with subsequent morbidity and mortality. A striking relation between poor intrauterine growth and either death or handicap in the asphyxia group emphasised the value of growth measurements as a predictor of outcome. The overall incidence of seizures was 1.6 per 1000 term deliveries. There was a significant correlation between the seizure incidence and the intrapartum mortality rate. The incidence of seizures secondary to asphyxia in term infants, occurring less than 48 hours after delivery, may be a valuable index of the quality of perinatal care.