Time course of metabolic status in pregnant women: The Japan Environment and Children's Study

We aimed to evaluate the metabolic status of pregnant women by assessing metabolic biomarkers of participants in the Japan Environment and Children's Study, a nationwide, multicenter, pregnancy and birth cohort.

Pregnant women aged 14-50 years were studied in 15 centers across Japan. Clinical information was obtained using self-administered questionnaires. Blood samples were taken during the first two trimesters to measure metabolic biomarkers. Samples were divided into seven groups according to the weeks of pregnancy.

Among 82,972 pregnant women, 43 had only type 1 diabetes, 78 had only type 2 diabetes, 2,315 had only gestational diabetes and 354 had only dyslipidemia. Glycated hemoglobin, total cholesterol, low-density lipoprotein cholesterol and triglyceride across all the percentiles increased as prepregnancy body mass index increased, whereas high-density lipoprotein cholesterol levels across all the percentiles decreased as body mass index increased. Glycated hemoglobin was high in participants with type 1 diabetes or type 2 diabetes only, but not in those with gestational diabetes or hyperlipidemia only. Participants with type 2 diabetes or dyslipidemia only had high triglyceride in the first trimester, which then decreased in the second trimester. Participants with type 2 diabetes only also showed low high-density lipoprotein cholesterol, whereas participants with dyslipidemia only showed high total cholesterol and low-density lipoprotein cholesterol throughout.

Metabolic biomarkers were affected by blood sample timing and underlying metabolic disease. The Japan Environment and Children's Study will clarify the influences of metabolic status during pregnancy on the health and development of the offspring in future studies.