Maternal thyroid function, prepregnancy obesity and gestational weight gain-The Generation R Study: A prospective...

Area of Science:

• Reproductive Endocrinology
• Maternal-Fetal Medicine
• Thyroidology

Background:

• Maternal obesity and excessive gestational weight gain are significant risk factors for adverse pregnancy outcomes.
• Thyroid hormones play a crucial role in regulating metabolism and body weight in adult populations.

Purpose of the Study:

• To investigate the association between maternal thyroid function, specifically thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels, in early pregnancy with maternal prepregnancy body mass index (BMI) and gestational weight gain.
• To explore potential differences in these associations based on thyroid status (hypothyroidism/hyperthyroidism).

Main Methods:

• A population-based prospective cohort study involving 5726 mothers.
• Maternal TSH and FT4 levels were measured in early pregnancy (13.5 weeks gestation).
• Maternal weight was recorded before pregnancy and during each trimester to assess BMI and gestational weight gain.

Main Results:

• Elevated maternal TSH levels were significantly associated with higher prepregnancy BMI and greater total gestational weight gain.
• Conversely, higher maternal FT4 levels were linked to lower prepregnancy BMI and reduced gestational weight gain.
• Maternal hypothyroidism correlated with increased prepregnancy BMI and early pregnancy weight gain, while hyperthyroidism showed opposite associations.

Conclusions:

• Early pregnancy thyroid function, indicated by TSH and FT4 levels, is associated with maternal prepregnancy BMI and gestational weight gain.
• These findings highlight the importance of monitoring thyroid function during pregnancy.
• Further research is warranted to elucidate the maternal and fetal consequences of these associations.