Blood Glucose in Pregnant Non-diabetic Women During Treatment With Betamethasone for Fetal Lung Maturation

Antenatal corticosteroid administration is an important treatment to reduce the incidence of neonatal respiratory distress syndrome, and improve neonatal outcomes of babies born premature.

Administration of betamethasone however also affects the maternal glucose homeostasis, and it is well-known that in pregnant women with diabetes, the administration of glucocorticoids can lead to significant maternal hyperglycemia, and hypoglycemia in the neonate, unless the insulin dosage is adjusted accordingly. Administration of betamethasone also affects the glucose homeostasis in pregnant non-diabetic women. However, only few studies have investigated the changes in the blood glucose levels in non-diabetic pregnant women, and a more accurate depiction of the glycemic response to betamethasone can be obtained by continuous glucose monitoring.

Recruitment of participants will occur upon their arrival with symptoms of threatened preterm birth, when it is decided to start treatment with betamethasone for fetal lung maturation.

To measure blood glucose levels in the pregnant women, a continuous glucose monitor (CGM) will be used.

Further, blood samples will be collected on days 1-6 after inclusion, for measurement of: Insulin, blood glucose, 3-hydroxybutyrat, HgbA1c, CRP and leucocytes.

Urine dipstick test for ketones and glucose will be performed twice daily. After delivery, a blood sample will be extracted from the umbilical cord for measurement of Ph, base-excess, glucose, insulin c-peptide and inflammatory markers.

Information on hypoglycemia and/or the need for early feeding of the infant after birth will be recorded.

Perspectives:

The results of this study will help us understand how the administration of betamethasone affects maternal blood glucose levels. If it is found, that administration of betamethasone causes significant hyperglycemia in the pregnant women, it may be important to measure and treat hyperglycemia during betamethasone treatment, to ensure the effect of betamethasone and prevent neonatal complications due to hypoglycemia.

Inclusion criteria

• Pregnant in gestational week 24+0 - 34+0 admitted with symptoms of threatened preterm birth:

• Premature contractions and shortening of the cervix, or
• Preterm premature rupture of membranes.
• Treatment with betamethasone for fetal lung maturation is planned, or started (maximum 4 hours before inclusion)
• Age over 18 years
• Read and understand Danish

Exclusion criteria

• Multiple pregnancy
• Diabetes
• Pre-existing maternal use of medications that affect glucose metabolism