Improved maternal glycaemic control for type 1 diabetes in pregnancy following transition between automated insulin delivery systems: a case report — ASN Events
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Improved maternal glycaemic control for type 1 diabetes in pregnancy following transition between automated insulin delivery systems: a case report (#130)

Alia N Tun Ismail 1 2 , Michael Do 1 2 , Mina Toumas 1 2 , Elizabeth Fletcher 1 2 , Nima Mathew 1 2 , David Simmons 1 2 3
  1. Campbelltown Hospital, Campbelltown, NSW, Australia
  2. Macarthur Diabetes Service, Campbelltown Hospital, Campbelltown, NSW, Australia
  3. School of Medicine, Western Sydney University, Campbelltown, NSW, Australia

Aim

To describe the effect of transitioning between hybrid automated insulin delivery (AID) systems on glycaemia during pregnancy for a woman with type 1 diabetes mellitus (T1DM).

Methods

We report the case of a woman with long-standing T1DM switching between two AID systems during pregnancy due to persistent hyperglycaemia. Continuous Glucose Monitor (CGM) metrics, including time in range (TIR), mean glucose, coefficient of variation (CV), and total daily insulin requirements (TDD), were reviewed before and after pump transition. Maternal and neonatal outcomes were assessed.

Results

X is a 30-year-old female gravida 3 parity 1 with a previous third trimester stillbirth. Preconception and from early pregnancy, insulin delivery was via AID using Medtronic MiniMed 780G pump and Guardian 4 sensor. She attended the preconception clinic with pre-pregnancy TIR36%, CV 42.5%, mean glucose ≈9.8mmol/L and TDD 48.2 units. 

Despite intensive multidisciplinary care and insulin titration, glycaemia remained suboptimal during the first and second trimesters, with TIR consistently <60%, mean glucose ≈8.7 mmol/L, CV 31.9% and increasing insulin requirements of up to 93.5 units TDD. Growth ultrasounds showed a large-for-gestational-age fetus with abdominal circumference and estimated fetal weight greater than 99th centile as well as polyhydramnios.

At 29+4 weeks gestation, X transitioned to the YpsoPump/Dexcom G6/CamAPS AID. Within 3 days following transition, TIR improved to 80%, mean glucose decreased to ≈6.0 mmol/L andglycaemic variability reduced (CV 25%). Although TDD continued to increase to a peak of 115.4 units during pregnancy, she sustained near-euglycaemia through late gestation. 

A live male infant was born at 36+6 weeks via emergency caesarean section due to failure to progress following induction of labour. Pregnancy outcomes included macrosomia (4470g), neonatal hypoglycaemia (1.2mmol/L) and postpartum haemorrhage.

Conclusion

This case demonstrates in a high risk and high anxiety pregnancy (with prior stillbirth and current fetal excess growth), how switching AID resulted in rapid and marked improvement in glycaemia. Existing health insurance and 4-year pump replacement timing allowed this switch to occur. Individual variability in response to closed-loop algorithms emphasises the need for subsidised, timely access to personalised diabetes technology before and during pregnancy.