Brian M. Casey

Background: To examine the incidence of overt hypothyroidism 1 and 5 years after pregnancies where screening before 21 weeks identified subclinical hypothyroidism (SH) or hypothyroxinemia (HT). Methods: Secondary analysis of two multicenter treatment trials for either SH or HT diagnosed between 8 and 20 weeks gestation. Current analyses focus only on individuals randomized to the placebo groups in the two parallel studies. SH was diagnosed with thyrotropin (TSH) ≥4.0 mU/L and normal free T4 (fT4) (0.86–1.9 ng/dL). HT was diagnosed with normal TSH (0.08–3.99 mU/L) but fT4 p < 0.001) and year 5 (15.6% vs. 2.6%, p < 0.001) for participants with SH compared with those with HT. This progression was more common in individuals with TSH values >10 mIU/mL. Baseline TPO level >50 IU/mL in participants with SH was associated with higher rates of hypothyroidism at year 1 (26.7% vs. 6.5%, odds ratio [OR] = 5.3 [confidence interval (CI) 2.6–10.7]) and year 5 (30.5% vs. 7.5%, OR = 5.4 [CI: 2.8–10.6]) compared with those with TPO levels ≤50 IU/mL. For participants with HT, no differences in overt hypothyroidism were seen at 1 year related to baseline TPO level >50 IU/mL (1/10 (10%) vs. 6/218 (2.8%), OR = 3.9 [CI: 0.43–36.1]), but more participants with TPO levels >50 IU/mL developed hypothyroidism by year 5 (2/10 (20%) vs. 4/218 (1.8%), OR = 13.4 [CI: 2.1–84.1]). Conclusion: SH is associated with higher rates of overt hypothyroidism or thyroid replacement therapy within 5 years of delivery than is HT when these conditions are diagnosed in the first half of pregnancy.

Objective The main purpose of this article is to evaluate whether identification and treatment of women with mild gestational diabetes mellitus (GDM) during pregnancy affects subsequent maternal body mass index (BMI), anthropometry, metabolic syndrome, and risk of diabetes. Study Design This is a follow-up study of women who participated in a randomized controlled treatment trial for mild GDM. Women were enrolled between 5 and 10 years after their index pregnancy. Participants underwent blood pressure, height, weight, and anthropometric measurements by trained nursing personnel using a standardized approach. A nurse-assisted questionnaire regarding screening and treatment of diabetes or hypercholesterolemia, diet, and physical activity was completed. Laboratory evaluation included fasting serum glucose, fasting insulin, oral glucose tolerance test, and a lipid panel. Subsequent diabetes, metabolic syndrome, obesity, and adiposity in those diagnosed with mild GDM and randomized to nutritional counseling and medical therapy (treated) were compared with those who underwent routine pregnancy management (untreated). Multivariable analyses were performed adjusting for race/ethnicity and years between randomization and follow-up visit. Results Four-hundred fifty-seven women with mild GDM during the index pregnancy were included in this analysis (243 treated; 214 untreated) and evaluated at a median 7 years after their index pregnancy. Baseline and follow-up characteristics were similar between treatment groups. Frequency of diabetes (9.2 vs. 8.5%, p =0.80), metabolic syndrome (32.2 vs. 34.3%, p =0.63), as well as adjusted mean values of homeostasis model assessment for insulin resistance (2.5 vs. 2.3, p =0.11) and BMI (29.4 vs. 29.1 kg/m², p =0.67) were also not different. Conclusion Identification and treatment of women with mild GDM during pregnancy had no discernible impact on subsequent diabetes, metabolic syndrome, or obesity 7 years after delivery.