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Good glycemic control in patients with gestational diabetes mellitus (GDM) is not associated with reduced GDM-associated complications in twin pregnancies, according to a recent study published in the American Journal of Obstetrics & Gynecology.
- Good glycemic control in patients with gestational diabetes mellitus (GDM) does not appear to reduce GDM-associated complications in twin pregnancies.
- GDM is more prevalent in twin pregnancies, but the associated complications might not be as relevant or common as in singleton pregnancies.
- Due to increased metabolic requirements in twin pregnancies, there might be a necessity to set twin-specific fasting and postprandial glycemic targets for GDM management.
- The retrospective cohort study included 105 GDM cases matched with 315 controls. Despite efforts to maintain good glycemic control, there were no significant differences in neonatal morbidity or selected secondary outcomes between patients with and without GDM.
- The study's findings suggest a need for additional research, particularly on maternal diet and average blood glucose levels, to better understand the implications of GDM in twin pregnancies.
Approximately 6% to 10% of pregnancies are impacted by GDM, leading to adverse outcomes such as accelerated fetal growth, macrosomia, and neonatal complications. GDM presents more often in twin pregnancies, but associated complications may be less relevant or common regardless of GDM.
It may be necessary to implement twin-specific fasting and postprandial glycemic targets for GDM in twin pregnancies because of increased metabolic requirements. To evaluate the association between maternal glycemic control and GDM-related complications, investigators conducted a retrospective cohort study.
Participants included patients who gave birth from January 1, 2011, to December 31, 2020, after a twin pregnancy complicated by GDM. A control group of patients with twin pregnancies but not GDM was also included in the analysis, being matched to twin pregnancies with GDM through the institutional perinatal database.
Exclusion criteria included pregestational diabetes, complications by stillbirth, fetal anomaly, preterm birth, monochorionic twin pregnancy complicated by twin-to-twin transfusion syndrome or selective fetal growth restriction, monoamniotic twin pregnancy, and lack of information on glycemic control.
Maternal glycemic control, described by study authors as, “the proportion of fasting and postprandial glucose values within target: fasting level below 5.3 mmol/L (95 mg/dL), 1-hour postprandial glucose below 7.8 mmol/L (140 mg/dL), or 2-hour postprandial glucose below 6.7 mmol/L (120 mg/dL),” was measured at the last 3 clinic visits for patients with GDM.
Neonatal morbidity and small for gestational age (SGA) twin were the primary outcomes of the analysis. Neonatal morbidity included large for gestational age twin, neonatal hypoglycemia, neonatal jaundice, shoulder dystocia or birth trauma, and neonatal intensive care unit admission at term.
Patients with GDM attended visits to a diabetes clinic every 1 or 2 weeks and monitored blood glucose levels using a glucometer 4 times a day. Patients who did not meet the target glucose levels started metformin or insulin treatment.
There were 105 cases matched to 315 controls included in the analysis. Similar characteristics were observed between the 2 groups, but preexisting hypertension and birthweight below the third centile were greater in the GDM group. Patients were aged a mean 26.4±3.1 weeks and GDM diagnosis, with 44.8% needing medical treatment.
Overall, 2-hour postprandial, and any postprandial glucose values were significantly higher in patients with diet-treated GDM compared to this with medically-treated GDM. Composite neonatal morbidity was reported in 32.4% of the GDM group. An SGA newborn was reported in 43.8% of the GDM group and 34% of the non-GDM group.
The distribution of overall, fasting, and postprandial glycemic control did not significantly differ between patients with and without composite neonatal morbidity or selected secondary outcomes. These findings were similar when stratified by diet vs medical treatment.
Glycemic control also did not significantly differ in patients with an SGA newborn vs those without an SGA newborn in the overall study population. However, higher overall and fasting glucose levels were observed among patients with an SGA newborn in the diet-treated GDM subgroup.
Neonatal morbidity risk was not significantly decreased in GDM pregnancies with good glycemic control vs suboptimal control, at 32.1% vs 32.7%, respectively. Increased SGA odds were observed in patients with good glycemic control compared to non-GDM pregnancies, at 49.1% vs 34%, respectively. In diet-treated GDM patients, the risk of SGA was 65.5%.
These results indicated glycemic control is not associated with reduced GDM-related complication risk. Investigators recommended further research on maternal diet and mean blood glucose levels to confirm these findings.
Berezowsky A, Ardestani S, Hiersch L, et al. Glycemic control and neonatal outcomes in twin pregnancies with gestational diabetes mellitus. Am J Obstet Gynecol.2023;229:682.e1-13.doi:10.1016/j.ajog.2023.06.046