Jeremy N. Oats

Incidence and Severity of Gestational Diabetes Mellitus According to Country of Birth in Women Living in Australia

Gestational diabetes mellitus (GDM) was diagnosed in 1928 of 35,253 (5.5%) tested pregnancies at the Mercy Maternity Hospital in Melbourne between 1979 and the end of 1988. Compared with women born in Australia and New Zealand, the incidence of GDM was significantly greater in women born on the Indian subcontinent (15%); in women born in Africa (9.4%), Vietnam (7.3%), Mediterranean countries (7.3%), and Egypt and Arabic countries (7.2%); and in Chinese (13.9%) and other Asian (10.9%) women. There was no significant difference for women born in the United Kingdom and northern Europe (5.2%), Oceania (5.7%), North America (4.0%), or South America (2.2%). With the World Health Organization criteria as a guide to the severity of hyperglycemia, compared with mothers born in Australia and New Zealand, there were significant increases in the incidences of the more severe grades of GDM in parturients born in the Mediterranean region, Asia, the Indian subcontinent, Egypt, and Arabic countries. The incidence of GDM increased significantly in all racial groups, rising from 3.3% during 1979–1983 to 7.5% during 1984–1988.

Preeclampsia in Twin Pregnancy‐Severity and Pathogenesis

The incidence of preeclampsia in a consecutive series of 642 twin pregnancies was 25.9% compared with 9.7% in singleton pregnancies (p less than 0.001); in primiparas it was 35.2% and in multiparas 20.4% (p less than 0.001). Preeclampsia in twin pregnancies was more commonly of early onset (p less than 0.001) and the maternal disease more severe as assessed by the incidences of severe hypertension (p less than 0.001), proteinuria (p less than 0.004), and eclampsia (p less than 0.01). There were 1 maternal and 12 perinatal deaths. Oestriol excretion before the emergence of preeclampsia was lower in patients with severe compared with milder preeclampsia (p less than 0.05) as was plasma glucose concentration (p less than 0.05). Mean birth and placental weights according to gestation, tended to be lower in the severe group compared with uncomplicated cases and those with milder preeclampsia, as were also the placental-fetal weight ratios. The similarity of results with those already reported for singleton pregnancy suggested a similar pathogenesis for preeclampsia in twin and singleton pregnancies.

The Long‐Term Follow‐up of Women with Gestational Diabetes

Summary: Four hundred and forty‐seven women who had gestational diabetes have been retested at intervals from 1 to 12 years following diagnosis; 49 (11%) were found to be diabetic and 35 (7.8%) had impaired glucose tolerance using the WHO criteria. An abnormal glucose tolerance test in the puerperium and obesity at the time of retesting had significant associations with abnormal glucose tolerance at follow‐up. However, the best predictive factor of the likelihood of the development of significant hyperglycaemia was the recurrence of gestational diabetes in a subsequent pregnancy, since 28% of these women were diabetic and a further 4% had impaired glucose tolerance at the time of follow‐up. These findings indicate that the criteria used for the diagnosis of gestational diabetes at the Mercy Maternity Hospital, Melbourne (1‐hour ≥ 9 mmol/1 together with a 2‐hour ≥ 7 mmol/1) are appropriate for an Australian population.

Glucose Tolerance in Twin Pregnancy

Summary: Over a 10‐year period, 50 g oral glucose tolerance tests were performed in 288 patients with twin pregnancies and 20,030 with singleton pregnancies. In multiple pregnancies the fasting blood glucose value was significantly reduced (P<0.001), but the values at 1, 2 and 3 hours were not significantly different from those in singleton pregnancies. The incidences of both gestational diabetes (5.6%) and gestational hypoglycaemia (3.9%) in twin pregnancies were more than double those in singleton pregnancies (2.5% and 1.7%, respectively) (P<0.01). As the risk of perinatal death is increased in these patients, glucose tolerance tests should be performed in all patients with twin pregnancies.

Quality of survival of infants with critical fetal reserve detected by antenatal cardiotocography

During the 8-year period 1973 to 1980, antenatal cardiotocographic monitoring was performed on 3,006 high-risk pregnancies selected from a total obstetric population of 37,856 patients. A critical fetal reserve was detected in 72 patients (2.3%) whose pregnancies resulted in 20 perinatal deaths and 52 infants who survived the neonatal period; 45 of these infants have been assessed at ages ranging from 2 months to 8 years, 9 months. Growth was below the tenth percentile in 25.0% for weight, 23.3% for length, and 22.5% for head circumference at the review examination. Neurological abnormalities were detected in 12 infants but the abnormality was major in only four, including one who has familial interstitial polyneuropathy. The quality of survival of infants delivered of pregnancies complicated by critical fetal reserve is satisfactory; 93.2% had no neurological impairment likely to interfere with quality of life and indeed 13.5% had superior intelligence. Cardiotocographic evidence of critical fetal reserve does not signify that the fetus is doomed; delivery by cesarean section is indicated if the fetus is viable and has no ultrasonic evidence of untreatable major malformation.

The Emergence of Diabetes and Impaired Glucose Tolerance in Women Who Had Gestational Diabetes

Diabetes mellitus is a common medical disorder that leads to significant morbidity and mortality. In the Australian community it is estimated that 3.4% of the population over 24 years of age suffer from the disease (Glatthaar etal., 1985). A number of factors, particularly hormonal, act during pregnancy to increase blood sugar levels but pregnant women with normal pancreatic function can maintain these levels within the normal range. The small proportion of women who are unable to do this develop gestational diabetes. Following the removal of the fetus and placenta this glucose intolerance usually disappears, but in some patients it re-emerges at a later date (Kuhl etal., 1984).

Labour‐Onset Pre‐Eclampsia

Summary: In a consecutive series of 1,201 singleton pregnancies with preeclampsia, the onset occurred during labour in 290 (24.1 %). There was no difference between the primparous and parous patient in this respect (25.9% v 20.7% P < 0.10). The tendency for pre‐eclampsia to develop during labour increased with advancing maturity of the pregnancy and seldom occurred before 38 weeks of gestation; this was again equally true of the primiparous and parous patient, as was the incidence of severe hypertension (diastolic pressure > 110mm Hg) (36.1% v 34.1%). The high incidences of severe hypertension (35.5%), proteinuria (41.7%), and eclampsia (2.1%), and the I maternal death testified to the severity of the disease process and the need for aggressive management. After delivery, the clinical signs tended to subside rapidly, but the early third stage of labour was a time of maternal risk, irrespective of whether ergometrine or Syntocinon was the oxytocic agent administered. Analysis of perinatal results showed that the risk to the fetus was minimal.

Timely Diagnosis by Cardiotocography of Critical Fetal Reserve Due to Fetofetal Transfusion Syndrome

Summary: In a review of 90 twin pregnancies monitored by antenatal cardiotocography there were 8 cases of subsequently proven fetofetal transfusion syndrome. In 2 of these evidence of severe fetal stress had indicated immediate delivery; the 4 babies survived in circumstances that were perilous. In 1 case there was no evidence of critical fetal reserve but the recipient twin died, this probably representing an acute fetofetal transfusion during labour. In the 5 milder cases with no evidence of stress on cardiotocography, all babies survived and they required minimal or no treatment for problems relating to the fetofetal transfusion. In multiple pregnancy the cardiotocograph offers the additional bonus of detection of fetal compromise due to fetofetal transfusion.

Nonstressed antepartum cardiotocography in patients undergoing elective cesarean section—Fetal outcome

In a prospective study of 409 patients monitored with nonstressed antepartum cardiotocography and delivered by elective cesarean section, cardiotocography was requested for 170 because of clinical indications. This group had higher incidences of abnormal cardiotocography (p less than 0.001), fetal growth retardation (p less than 0.001) and neonatal deaths (p less than 0.025) than had the group without such requests, suggesting that clinicians effectively selected the high-risk pregnancy for testing of fetal well-being. Cardiotocographic evidence of critical reserve was found in 17 of 170 patients (10%) tested for a clinical indication and in none of the 239 patients in the control group. Patients with abnormal cardiotocography results had significantly higher incidences of cord arterial blood pH less than 7.26 (p less than 0.05) and Apgar scores of less than 6 at 1 minute (p less than 0.001), showing that an abnormal cardiotocogram is indicative of a fetus at risk of having hypoxia.

Antepartum cardiotocography--an audit.

Summary: Between 1981 and 1986, 9,840 women were monitored by antepartum nonstressed cardiotocography (CTG). A satisfactory fetal reserve pattern was detected in 91%, a reduced reserve pattern in 8% and a critical reserve pattern in 1%. The incidences of fetal growth retardation, Apgar score < 6 at 1 minute, perinatal mortality and Caesarean section all increased significantly (p < 0.001) as the degree of cardiotocographic fetal reserve worsened. Intrauterine growth retardation and/or low urinary oestriol excretion was associated with a highly significantly increased incidence of abnormal CTG traces (14.2%, p < 0.001).