Effect of Glycemic Control During Labor on Neonatal Hypoglycemia Examined

Despite the paucity of evidence available for review regarding glycemic control in mothers with types 1 and 2 diabetes during labor and delivery, the current available evidence may not be of high enough quality to reach a conclusion as to whether or not tight glycemic control is needed, according to a systematic review published in Diabetes Medicine.

Researchers identified and conducted a systematic review of 23 studies (n=2835 women) regarding whether in-target compared with out-of-target glycemic control was associated with a lower risk for subsequent neonatal hypoglycemia in women diagnosed with type 1 diabetes (T1D), type 2 diabetes (T2D), or gestational diabetes (GD). 

All were cohort studies representing women from North America, New Zealand, and Australia.  Not all studies included in the review contained all 3 groups of women, as 7 only included women with T2D, 4 with only women diagnosed with GD, and the remaining 12 included a combination of women with all 3 types of diabetes. 

When studying intrapartum glucose and neonatal hypoglycemia, researchers found no statistically significant difference in 12 of the studies.  Six studies showed a relationship between the two, with 1 study finding a significant correlation in 107 women with T1D (r = 0.33; P <.001).  Five other studies found a relationship in at least 1 analysis performed within the study but not in all analyses performed.  Some studies utilized continuous glucose monitoring, finding a relationship between longer percentage of time with neonatal glucose levels >7 mmol/L and subsequent infant hypoglycemia. Results of these 6 studies reporting a relationship between intrapartum glucose and neonatal hypoglycemia did not adjust for known potential confounders.

Of the 12 studies that did not find a relationship between intrapartum glucose level and neonatal hypoglycemia, 1 included a notably large cohort group of 733 women with gestational diabetes.  Another study included 174 women with T1D (229 pregnancies) and found no relationship between maternal glycemia during labor and neonatal hypoglycemia 3 hours after birth in neonates (r = 0.12; P =.29).  When preterm deliveries were excluded from the analysis, there was still no relationship found.

Researchers concluded that the evidence is inconsistent in finding a relationship between intrapartum glucose levels and neonatal hypoglycemia, or lack thereof. Therefore, conclusions regarding tight glycemic control during delivery cannot be made based upon the current quality of evidence as even studies reporting a positive association did not perform analyses on potential confounding variables that could have influenced the study findings.  High quality studies are needed to either support current guidelines or allow for a more relaxed approach to glycemic control that would result in similar neonatal outcomes.

Reference

Yamamoto JM, Benham J, Mohammad K, Donovan LE, Wood S. Intrapartum glycaemic control and neonatal hypoglycaemia in pregnancies complicated by diabetes mellitus: a systematic review. Diabet Med. 2018;35:173-183.