The timing of delivery in diabetic pregnancy: a 10-year review

Antenatal management of gestational diabetes mellitus can improve neonatal outcomes

OBJECTIVE

Pregnancies complicated with gestational diabetes mellitus (GDM) are at a higher risk for caesarean and instrumental deliveries as well as adverse neonatal outcomes such as fetal overgrowth, hypoglycaemia and neonatal intensive care admission. Our primary objective was to describe neonatal outcomes in a sample that included term infants of both GDM mothers and mothers with normal glucose tolerance (NGT).

DESIGN AND SETTING

this cross-sectional study included 599 term babies born between September and October 2010 at Royal Prince Alfred Hospital, Sydney, Australia. Maternal and neonatal data were collected from medical records and a questionnaire. Glycaemic control data was based on third trimester HbA1c levels and self-monitoring blood glucose levels (BGL). Univariate associations between GDM status and maternal demographic factors, as well as pregnancy outcomes, were estimated using χ(2) tests and t-tests, as appropriate.

FINDINGS

of 599 babies, 67(11%) were born to GDM mothers. GDM mothers were more likely to be overweight/obese and of Asian ethnicity. Good glycaemic control was achieved in most GDM mothers. GDM babies were more likely to have been induced (p=0.013) and delivered earlier than non-GDM mothers (p<0.001), and they were also more likely to be breastfed within one hour of birth.

CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

in this study, GDM infants were more likely to be induced and delivered earlier but otherwise they did not have significantly different neonatal outcomes compared to infants of NGT mothers. This can be attributed to the good GDM control by lifestyle modification and insulin if necessary. The role of labour induction in GDM pregnancies should be further investigated. Midwives have an important role in maternal education during pregnancy and in the postnatal period.

Obstetric complications due to autoantibodies

Autoimmune diseases are most common and most active in young women; it is therefore not uncommon for obstetricians and physicians to encounter pregnant women with these conditions, and knowledge of the potential maternal, foetal and neonatal complications is essential for good clinical management. The most common maternal autoimmune endocrine conditions in pregnancy are insulin-dependent diabetes mellitus and thyroid disease. Other relatively common non-endocrine autoimmune conditions include systemic lupus erythematosus and anti-phospholipid syndrome. Much rarer autoimmune conditions include autoimmune thrombocytopenia, rheumatoid arthritis, myasthenia gravis and Addison's disease. In this chapter, we discuss autoimmune endocrine conditions and briefly mention some non-endocrine conditions of particular importance.

Is cellular fibronectin a biological marker for pre-eclampsia?

Cellular fibronectin (cFn) appears to be an important factor in the regulation of cell-cell interactions. It is mostly synthesised by endothelial cells and its increased circulating values are thought to correspond to the endothelial damage. As pre-eclampsia is considered a pathology of endothelial cells, our study was intended to see if this circulating protein is increased during pre-eclampsia and to determine from which moment in pregnancy these changes occur. We studied cFn longitudinally in 198 consecutive pregnant patients, with or without pathologies associated to pregnancy. We measured the cFn concentrations by ELISA four times during pregnancy with the monoclonal antibody A 134. The values of cFn increased throughout the normal pregnancy, but a significant increase was observed only after the 36th week of pregnancy (P<0.0001). The values of doubling time of cFn gradually decreased, being inverse to cFn concentrations. The values of cFn were significantly higher (3.53 microg/ml; P=0.0009) in the third trimester in the group of women who developed pre-eclampsia, as compared to normals (2.23 microg/ml). cFn could not be used as a predictor of pre-eclampsia, because the clinical symptoms of this pathology were already present at the time of measurement. Our data represent the first longitudinal study showing the increase of cFn values throughout normal and pre-eclamptic pregnancies.

Factors affecting fetal weight distribution in women with type I diabetes

OBJECTIVE

To identify factors independently affecting fetal weight in women with type I diabetes.

DESIGN

Prospectively recorded data in consecutive women with type I diabetes, between 1975-1992.

SETTING

Simpson Memorial Maternity Hospital, Edinburgh. Population Three hundred and two pregnancies with type I diabetes identified before pregnancy, with antenatal care and delivery in the Simpson Memorial Maternity Hospital, a singleton pregnancy, and the same diabetic physician.

METHODS

Normal ranges for birthweight were established for the total hospital population. All cases and the total population had pregnancy dating by ultrasound. The relation between standardised birthweight and explanatory variables was investigated using correlation analysis, t tests and chi2 tests as appropriate, and subsequently using multiple linear regression.

RESULTS

Standardised birthweight in cases, compared with the reference population, showed a unimodal, approximately normal distribution, markedly shifted to the right (mean + 1.26 SD). The most predictive variable was glycated haemoglobin concentration at 27-33 weeks, which explained 6.3% of the birthweight variance, while smoking explained 2.7% and maternal weight 2.0%. There was a trend towards a negative relationship with glycated haemoglobin concentration at 6-12 weeks. Smoking and glycated haemoglobin concentration were strongly intercorrelated.

CONCLUSIONS

Most of the variance in standardised birthweight remains unexplained, but glycated haemoglobin concentration at 27-33 weeks is the most powerful explanatory variable. Possible reasons why there is not a stronger relationship between markers of maternal glycaemia and birthweight are discussed.

Pregestational Diabetes Mellitus and Pregnancy

In a pregnancy complicated by diabetes the foetus is at increased risk of congenital malformations, macrosomia and stillbirth. For the mother, diabetes complications (retinopathy nephropathy) may worsen, and in this group there is a higher incidence of hypertension, pre-eclamptic toxaemia and intrauterine growth restriction. However, women with good control who are free of diabetic complications can expect a normal outcome.

Outcome of diabetic pregnancy with spontaneous labour after 38 weeks

One hundred and forty-eight patients with well controlled insulin dependent diabetes that were allowed to labour spontaneously from 1981 to 1994 were reviewed. There were 2 perinatal deaths, giving a perinatal mortality rate of 13.5/1000. One hundred and twenty-four patients (84 per cent) had a normal vaginal delivery, 13 (9 per cent) forceps delivery and 11 (7 per cent) caesarean section. Twenty-one infants (14 per cent) required admission to a Special Care Baby Unit. One third of infants weighed 4 Kg or more, however there was only 1 case of shoulder dystocia. We compared these results with those of the general hospital population of 1987. The 2 main differences are; 1) the Caesarean section rate in labour was higher for this diabetic group than for the general hospital population, 7 per cent versus 3.4 per cent, 2) the birth weight was heavier, 33 per cent of infants of the diabetic group weighed 4 Kg or more versus 18 per cent of the general hospital population. The other parameters were comparable. We conclude that conservative management of pregnancy in well controlled diabetic women is advantageous, resulting in a high vaginal delivery rate without an increase in shoulder dystocia, and a low perinatal morbidity and mortality rate.

Prevalence of polyhydramnios in the third trimester in a population screened by first and second trimester ultrasonography

AIMS

To determine the prevalence of polyhydramnios in a routine antenatal population, in which first and second trimester ultrasound screening for fetal abnormality had been performed and to examine the outcome in these pregnancies.

METHODS

A retrospective analytical survey of all obstetric ultrasound examinations performed in a university teaching hospital over a thirty-six month period. Polyhydramnios was defined as either the measurement of a single deepest pool of liquor > 8 cm (AFV) or according to the amniotic fluid index, the sum of a four quadrant measurement > 24 cm (AFI). Using the stated definitions, polyhydramnios was diagnosed in 37 women, 16 of whom had a raised AFI. The main outcomes of interest included the mode of onset of labour and mode of delivery (rates of spontaneous and induced labour, cesarean section deliveries), birth weight, presence or absence of fetal anomalies, and the perinatal outcome.

RESULTS

The prevalence of polyhydramnios in this study is lower (0.15% AFI > 24 cm and 0.36% AFV > 8 cm) than in previous studies. The association between polyhydramnios, maternal diabetes mellitus (10.8%), fetal abnormalities (5.4%) and fetal macrosomia (10.8%) was also lower than in past reports. There was a better overall fetal outcome compared with previous studies and no perinatal deaths were seen.

CONCLUSIONS

In this study, the prevalence of polyhydramnios in the third trimester was lower than in previous studies, as well as being associated with a better prognosis. This may have been the result of a combination of several factors. These include the introduction of multi-level ultrasound screening for fetal abnormality, and the improved care of diabetic women, and mothers with rhesus iso-immunisation.

Fetal growth in diabetic pregnancy

In summary, fetal macrosomia occurs in almost one third of diabetic pregnancies regardless of class. Abnormal fetal fat stores lead to difficult labor, dystocia, and birth injury as well as postnatal metabolic transition. The abnormal body fat distribution at birth may destine some of these infants to lifelong obesity. Abnormal fetal growth in diabetic pregnancy appears to occur with any elevations in maternal glucose levels, however modest. Detection of macrosomia is therefore a major goal of diabetic pregnancy management.

Diabetes

There is now strengthening evidence that meticulous control of maternal carbohydrate and fat metabolism before and during pregnancy in women with diabetes mellitus had positive benefits for the offspring, not only by reducing the incidence of congenital malformations, but also by diminishing fetal loss, reducing immediate neonatal complications and, in the long term, reducing unnecessary obesity, improving neuropsychological development and reducing the emergence of diabetes in the offspring at a relatively early age. Women who develop GDM are at a significant risk of developing NIDDM, and prevention of obesity, consumption of a high-fibre diet and possibly prophylactic hypoglycaemic therapy may reduce this otherwise inevitable progression, which will affect at least 50%.