Poster Presentation Australasian Diabetes in Pregnancy Society and Society of Obstetric Medicine Australia and New Zealand Joint Scientific Meeting 2021

Metformin use in Gestational Diabetes Mellitus; A Tertiary Hospital Experience. (#100)

Nishanthi S Pannila 1 , Lipi Chakravorty 1 , Christina Morrissey 1 , Melanie S Burkhardt 1 2 3 , Emily J Gianatti 1 , Krishnamurthy Chikkaveerappa 1
  1. Fiona Stanley Hospital, Perth, WA, Australia
  2. Department of Clinical Psychology and Neuropsychology, Fiona Stanley Fremantle Hospital group , Perth, WA, Australia
  3. Medical School, University of Western Australia, Perth, WA, Australia

Introduction: The use of metformin in the treatment of Gestational Diabetes Mellitus (GDM) is variable in Australia and worldwide. There is strong evidence that metformin is safe and efficacious during pregnancy in the short term1. During the COVID -19 pandemic, Fiona Stanley Hospital (FSH) offered women metformin as an alternative to insulin where clinically appropriate.

Aim: The aim of this study was to describe the clinical characteristics of the women receiving different treatments, and assess the efficacy and safety of metformin therapy in women with GDM.

Method: We retrospectively analysed the medical records of 157 women with GDM requiring pharmacotherapy at our site over nine months. Women were allocated to four treatment groups: metformin monotherapy (Group A), insulin monotherapy (Group B), metformin added to insulin (Group C), insulin added to metformin (Group D).

Results: There was no difference in the mean age (p= 0.30) and ethnicity (p=0.75) of the four treatment groups. Women commenced on insulin therapy (Group B) had higher body mass index (BMI) (p=0.03) and were more likely to have previous history of GDM (p≤0.01). 83 women with GDM were treated with metformin monotherapy during the study period. However, 60% of them needed addition of insulin to achieve glucose control.  66% of women reached optimal blood sugar control with less than maximum dose of metformin. 13% of the women experienced gastrointestinal side effects, however, there were no unplanned reviews or unplanned admissions noted during the study period. This group was commenced on therapy later in the pregnancy leading to shorter mean treatment duration (6.42 weeks) compared to other groups (11.16, 11.58 and 14.62 weeks for Groups B, C and D respectively) Group D were able to avoid insulin for a mean duration of 3.58 weeks when on metformin alone.

Among the four groups there were no significant difference in neonatal complications (p=0.47), birth weight (p= 0.80) and Neonatal intensive care unit (NICU) (p=0.92) admissions. Fewer total maternity complications (p≤0.01) were noted in Group A but this was driven by lower postpartum haemorrhage rates.

Conclusions

The metformin treated group had lower BMI and were at later gestational stage when metformin was commenced and there were no significant differences in neonatal outcomes as compared to the insulin group. However, 60% of women required addition of insulin and 13% had gastrointestinal side effects.

 

  1. Reference: Metformin versus insulin for the treatment of gestational diabetes Rowan, Janet A ; Hague, William M ; Gao, Wanzhen ; Battin, Malcolm R ; Moore, M Peter The New England journal of medicine, 08 May 2008, Vol.358(19), pp.2003-15