Higher hemoglobin levels are an independent risk factor for gestational diabetes

Niina Sissala,Sanna Mustaniemi,Eero Kajantie,Marja Vääräsmäki,Peppi Koivunen

doi:10.1038/s41598-022-05801-y

Abstract

Incidence of gestational diabetes (GDM) has increased rapidly. It poses significant risks for both mother and fetus affecting also negatively their longer-term metabolic heath. We asked whether early pregnancy maternal hemoglobin (Hb) levels, indicative for tissue oxygenation, would affect mother’s metabolic health and fetal outcome. We assessed in FinnGeDi, a Finnish multicenter case–control study for GDM (n = 1828), association of maternal 1st trimester Hb levels with metabolic parameters and perinatal outcome. Our data show that mothers with GDM had higher Hb levels compared to controls (mean difference 1.746 g/L). Hb levels associated positively with pre-pregnancy body mass index (BMI), fasting glucose levels and glucose levels in a glucose tolerance test and systolic and diastolic blood pressure (bp) levels. When assessed in quartiles the highest Hb quartile had more chronic and gestational hypertension and the most adverse outcome of the metabolic parameters, dose-dependency seen in bp, BMI and glucose levels. In a multivariable regression analysis Hb levels remained an independently associated parameter for GDM after adjusting for key covariates (OR 1.019, 95% CI [1.007; 1.031]). In conclusion, higher maternal Hb levels within the normal variation are an independent risk factor for GDM in this population but have little effect on perinatal outcome.

Highlights

Gestational diabetes mellitus (GDM) is an increasingly common public health and clinical problem complicating pregnancy[1,2]
Higher Hb levels in non-pregnant adults have been associated with obesity, adverse metabolism, higher blood pressure levels and increased inflammation[12,13,14], all associated with GDM, suggesting that lower Hb levels within the Hb reference range may associate with healthier maternal metabolism during pregnancy
Characteristics of the study population showed that women with GDM were older than the non-GDM controls and they had more comorbidities during pregnancy, such as pre-eclampsia and gestational hypertension (Table 1)

Summary

Introduction

Gestational diabetes mellitus (GDM) is an increasingly common public health and clinical problem complicating pregnancy[1,2]. The established maternal short-term risks associated with GDM include increased rates of gestational hypertension and pre-eclampsia, and an increased frequency of Caesarean s ections[7]. Higher Hb levels in non-pregnant adults have been associated with obesity, adverse metabolism, higher blood pressure (bp) levels and increased inflammation[12,13,14], all associated with GDM, suggesting that lower Hb levels within the Hb reference range may associate with healthier maternal metabolism during pregnancy. Previous studies with small selected Asian and Turkish populations have associated higher 1st trimester maternal Hb levels with an increased risk for GDM, pre-eclampsia and gestational hypertension[15,16,17,18]. The largest so far study with > 20,000 Chinese non-smoking singleton participants associated higher early pregnancy Hb levels with increased risk for GDM and pre-eclampsia while no information about the newborn parameters were r eported[19]. Increased information about the risks for GDM will eventually lead to better maternal and child health through improved primary prevention

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