Relationship Between Thyroid Function Tests and Birth Parameters at 41-Week-And-Above Pregnancies: A Prospective...

Area of Science:

• Obstetrics and Gynecology
• Endocrinology
• Perinatal Medicine

Background:

• Limited research exists on the association between thyroid hormones in late-term pregnancies (≥41 weeks) and key obstetric outcomes.
• Investigating these relationships is crucial for understanding potential risks and optimizing maternal-fetal care in advanced gestation.

Purpose of the Study:

• To examine the correlation between thyroid hormones (TSH, FT4) and birth timing, labor duration, fetal distress, PROM, and maternal hemogram.
• To compare these parameters between pregnancies at ≥41 weeks (late-term) and 37-38 weeks (control).

Main Methods:

• A cohort of 68 nulliparous women were divided into a late-term group (≥41 weeks, n=37) and a control group (37-38 weeks, n=31).
• Thyrotropin (TSH), free thyroxine (FT4), hemoglobin, and hematocrit levels were measured.
• Outcomes including birth type, labor duration, fetal distress, PROM, and postpartum hemogram changes were analyzed.

Main Results:

• Lower FT4 levels were significantly associated with fetal distress (p < 0.05) and a negative linear relationship with newborn weight (p < 0.05), indicating higher weight with lower FT4.
• No significant differences were found between groups for TSH/FT4 values, birth types, labor duration, or postpartum hemogram changes (p > 0.05).
• No significant relationship was observed between TSH/FT4 and PROM, labor duration, or hemogram changes (p > 0.05).

Conclusions:

• Thyroid hormone levels (TSH/FT4) may play a role in the mature and late-mature stages of pregnancy.
• FT4 levels show a potential association with fetal distress risk, birth type, and newborn weight.
• Further research is warranted to elucidate the clinical significance of these findings in late-term pregnancies.