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First trimester isolated maternal hypothyroxinaemia: adverse maternal metabolic profile and impact on the obstetrical outcome
Author(s) -
Furnica Raluca M.,
Gruson Damien,
Lazarus John H.,
Maiter Dominique,
Bernard Pierre,
Daumerie Chantal
Publication year - 2017
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.13301
Subject(s) - medicine , euthyroid , pregnancy , body mass index , gestational diabetes , obstetrics , thyroid function , overweight , gestational age , gestation , thyroid , endocrinology , genetics , biology
Summary Background Isolated maternal hypothyroxinaemia ( IH ) is defined as low maternal FT 4 (<5th percentile) and normal thyroid‐stimulating hormone. There is concern on its potential negative effects on the mother and offspring. Objective We aimed to evaluate the prevalence of IH and to assess the consequences of hypothyroxinaemia on the maternal and foetal outcomes. Subjects and methods From a total of 1300 consecutive pregnant women recruited during the prenatal screen (mean gestational age, 11·8 weeks), thyroid function parameters were assessed in 879 women. After exclusion of women with T4 supplements, with twin pregnancies and with diabetes, data from 783 women were included. Maternal and neonatal outcomes in 55 selected women with IH and negative thyroid auto‐antibodies without thyroid disorders or pregnancy achieved through assisted reproductive techniques were compared with a selected euthyroid control group ( N = 165). Results Among the 783 non diabetic singleton pregnant women, 68 women (8·7%) were identified with IH . When compared to the selected euthyroid controls, selected women with hypothyroxinaemia had significantly increased body mass index ( BMI ) in preconception ( P = 0·003), in the first trimester ( P = 0·004) and at the time of delivery ( P = 0·001). At term, foetal breech presentation and caesarean section rate were significantly higher ( P = 0·006 and P = 0·026, respectively) than in the euthyroid controls. A significant increase in macrosomia was also noted ( P = 0·026). Conclusion The prevalence of hypothyroxinaemia in early pregnancy was of 8·7%. IH is associated with an increased maternal BMI and is related with a risk of breech presentation, a significant increase in macrosomia and caesarean sections. Screening should consider overweight as risk factor for hypothyroxinaemia.