Declining Insulin Requirements in Late Pregnancy: A Cause for Concern? [07D

Abstract

INTRODUCTION: There is conflicting data on whether diminishing insulin requirement at the end of pregnancy is a sign of placental insufficiency. This study gathered descriptive data on women with diminishing insulin requirement and their obstetric and neonatal outcomes. METHODS: This was a retrospective cohort study of women who received antenatal care between November 2017 and May 2019 in a clinic of endocrinologists and obstetricians. We hypothesized that women with a declining insulin requirement would have increased rates of placental dysfunction-related complications (oligohydramnios, IUGR, abnormal dopplers, non-reassuring antepartum testing, or a cesarean delivery for non-reassuring fetal heart tracing). RESULTS: Our cohort consisted of 157 women: 30 Type 1, 43 Type 2 and 84 gestational diabetics. Twenty-one (13%) experienced a drop in insulin with an average decline of 28% starting at 34 weeks. There was no significant difference in complications related to placental dysfunction (33% vs 24%; P=.37). There was a significantly increased rate of polyhydramnios (43% vs. 9%; P<.01). Women who experienced a decline in insulin delivered one week earlier (median 36w4d vs. 37w4d; P<.01). NICU admissions rates were higher (62% vs. 33%; P<.01) independent of gestational age, and were secondary to respiratory distress (52% vs. 24%; P<.01) as there were no differences in rates of treated hypoglycemia. CONCLUSION: We found no relationship between a decline in insulin requirement and placental function-related complications. Interestingly, we found higher rates of polyhydramnios and NICU admissions for respiratory distress regardless of gestational age, suggesting a decline in insulin requirement has a greater impact on the neonate after delivery.