Treatments for gestational diabetes

BACKGROUND

Gestational diabetes (GDM) affects 3% to 6% of all pregnancies. Women are often intensively managed with increased obstetric monitoring, dietary regulation, and insulin. However, there has been no sound evidence base to support intensive treatment. The key issue for clinicians and consumers is whether treatment of GDM improves perinatal outcome.

OBJECTIVES

To compare the effect of alternative treatment policies for GDM on both maternal and infant outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2009) and bibliographies of relevant papers.

SELECTION CRITERIA

Randomised controlled trials comparing alternative management strategies for women with GDM and impaired glucose tolerance in pregnancy.

DATA COLLECTION AND ANALYSIS

Two authors and a member of the Cochrane Pregnancy and Childbirth Group's editorial team extracted and checked data independently. Disagreements were resolved through discussion with the third author.

MAIN RESULTS

Eight randomised controlled trials (1418 women) were included.Caesarean section rate was not significantly different when comparing any specific treatment with routine antenatal care (ANC) including data from five trials with 1255 participants (risk ratio (RR) 0.94, 95% confidence interval (CI) 0.80 to 1.12). However, when comparing oral hypoglycaemics with insulin as treatment for GDM, there was a significant reduction (RR 0.46, 95% CI 0.27 to 0.77, two trials, 90 participants). There was a reduction in the risk of pre-eclampsia with intensive treatment (including dietary advice and insulin) compared to routine ANC (RR 0.65, 95% CI 0.48 to 0.88, one trial, 1000 participants). More women had their labours induced when given specific treatment compared to routine ANC (RR 1.33, 95% CI 1.13 to 1.57, two trials, 1068 participants). The composite outcome of perinatal morbidity (death, shoulder dystocia, bone fracture and nerve palsy) was significantly reduced for those receiving intensive treatment for mild GDM compared to routine ANC (RR 0.32, 95% CI 0.14 to 0.73, one trial, 1030 infants).There was a reduction in the proportion of infants weighing more than 4000 grams (RR 0.46, 95% CI 0.34 to 0.63, one trial, 1030 infants) and the proportion of infants weighing greater than the 90th birth centile (RR 0.55, 95% CI 0.30 to 0.99, three trials, 223 infants) of mothers receiving specific treatment for GDM compared to routine ANC. However, there was no statistically significant difference in this proportion between infants of mothers receiving oral drugs compared to insulin as treatment for GDM.

AUTHORS' CONCLUSIONS

Specific treatment including dietary advice and insulin for mild GDM reduces the risk of maternal and perinatal morbidity. However, it is associated with higher risk of labour induction. More research is needed to assess the impact of different types of intensive treatment, including oral drugs and insulin, on individual short- and long-term infant outcomes.

Gestational diabetes: a review of the treatment options

More than three decades since the original published description of gestational diabetes mellitus (GDM), no consensus exists regarding its implications or management. Targeting fetal macrosomia as the greatest morbidity, treatment strategies for this pregnancy-induced disease of insulin resistance have largely been modeled from therapies proven successful in pregnant women with type 2 diabetes mellitus. Surrounded by a rapidly expanding array of treatment options for insulin-resistant diabetes, potentially legitimate concerns about teratogenicity and fetal metabolic effects have limited clinical trials of insulin analogs and oral antihyperglycemic agents during pregnancy. So far, only insulin lispro and glyburide (glibenclamide) have been tested prospectively in randomized trials of women with GDM. In limited studies, both of these agents have compared favorably with standard insulin regimens, and neither appear to cause any fetal or neonatal harm. Although acknowledged by the American Diabetes Association (ADA) and the American College of Obstetricians and Gynecologists (ACOG), these seminal studies have not yet prompted a recommendation from either organization on how to utilize insulin analogs or oral antihyperglycemic agents in the treatment of GDM. Although they lack an evidence base for many therapeutic strategies for GDM, the current ADA and ACOG guidelines still provide a reasonable set of treatment recommendations.

Fetal subcutaneous tissue thickness (SCTT) in healthy and gestational diabetic pregnancies

OBJECTIVE

To determine reference values of fetal subcutaneous tissue thickness (SCTT) throughout gestation in a healthy population and to compare them with those from a population of pregnant women with gestational diabetes under standard therapy.

METHODS

Three hundred and three women recruited from a high-risk pregnancy clinic were classified as being healthy (n = 218) or as having gestational diabetes (n = 85) on the basis of a negative or positive oral glucose tolerance test, respectively. They were enrolled into the cross-sectional study at 20 weeks' gestation. Ultrasound examinations were performed approximately every 3 weeks until delivery at term. The mid-arm fat mass and lean mass (MAFM, MALM), the mid-thigh fat mass and lean mass (MTFM, MTLM), the abdominal fat mass (AFM) and the subscapular fat mass (SSFM) were evaluated. Time-specific reference ranges were constructed from the 218 healthy women and a conventional Student's t-test was performed to compare SCTT values between the two study groups throughout gestation.

RESULTS

Normal ranges, including 5th, 50th and 95th centiles of the distribution, were generated for each SCTT parameter obtained in each of the two groups of women. Significant differences were found between the two study groups at 37-40 weeks' gestation for MTFM, at 20-22 and 26-28 weeks for MTLM, at 31-34 and 35-37 weeks for MAFM, at 26-28 and 38-40 weeks for SSFM, and at 39-40 weeks for AFM, the mean residual values always being greater in gestational diabetic women than they were in the group of healthy pregnant women.

CONCLUSIONS

We provide gestational age-specific reference values for fetal SCTT. Fetal fat mass values, particularly in late gestation, are greater in women with gestational diabetes compared with healthy women. The reference values may have a role in assessing the influence of maternal metabolic control on fetal state.