A Follow-up Study of Peripheral Neurological and Biochemical Involvement in Gestational and Overt Diabetes Mellitus

'Hyperglycaemia in pregnancy' (HIP) is one of the most common antenatal complications, affecting about one in six pregnancies globally. HIP is sub-classified into two categories, namely 'gestational diabetes mellitus' (GDM) and 'overt diabetes mellitus' (ODM). Pregnancy is characterised by the accumulation of adipose tissue and a growing placenta, acting as endocrine organs, thus intensifying the hyperglycaemic environment and building up oxidative stress by dysregulation of metabolic pathways, instigating peripheral neuropathy.

Due to paucity in existing literature on neurological influences of GDM and ODM, this follow-up study was planned to detect subclinical peripheral neuropathy by nerve conduction studies (NCS) and its correlation with biochemical parameters among them.

Thirty-nine pregnant women were divided into three groups: control, GDM and ODM. The NCS (sural and ulnar nerves) and biochemical parameters, that is, fasting plasma glucose (FPG), glycated haemoglobin (HbA1c), serum fasting insulin, homeostatic model assessment of insulin resistance (HOMA-IR), serum chromium, serum N-carboxy-methyl lysine, total cholesterol, low-density lipoprotein, triglycerides and high-density lipoprotein, were recorded during different stages of gestation, that is, 24-28 weeks (first visit), 32-38 weeks (second visit) and 6-12 weeks after parturition (third visit).

Nerve conduction studies reveal significant alterations in diabetic pregnant groups compared to control pregnant women, particularly in sensory latencies and amplitudes of the sural and ulnar nerves. Significant hyperglycaemia (FPG, HbA1c), hyperinsulinaemia, and elevated HOMA-IR in GDM and ODM groups confirm insulin resistance and poor glycaemic control during pregnancy and postpartum. Chromium levels were markedly lower in diabetics (p = .001).

This study necessitates ongoing metabolic and neurological monitoring in GDM and ODM after childbirth. Early screening and focused interventions, including micronutrient supplementation and lifestyle modifications, may help avert progression to overt neuropathy and mitigate long-term complications.