Trimester-specific thyroid hormone reference ranges in Sudanese women

Area of Science:

• Endocrinology
• Reproductive Health
• Clinical Chemistry

Background:

• Trimester-specific reference ranges for thyroid hormones are crucial for monitoring pregnancy health.
• No established ranges exist for TSH, FT3, and FT4 in pregnant Sudanese women.
• This study addresses this gap by establishing these ranges.

Purpose of the Study:

• To establish trimester-specific reference ranges for TSH, FT3, and FT4 in healthy pregnant Sudanese women.
• To compare these ranges with those of non-pregnant women.

Main Methods:

• A longitudinal study of 63 pregnant women in Khartoum, Sudan.
• Inclusion of an age- and parity-matched control group of non-pregnant women.
• Measurement of TSH, FT3, and FT4 levels throughout pregnancy and in controls.

Main Results:

• Trimester-specific median (5th-95th centile) ranges were established for TSH, FT3, and FT4.
• TSH levels increased across trimesters, while FT3 and FT4 were highest in the first trimester.
• Pregnant women showed significantly lower TSH, FT3, and FT4 levels compared to non-pregnant controls (P < 0.001).

Conclusions:

• This study provides the first trimester-specific reference ranges for TSH, FT3, and FT4 in pregnant Sudanese women.
• Pregnancy appears to suppress TSH, FT3, and FT4 levels in healthy women.
• These findings are vital for accurate thyroid function assessment during pregnancy in this population.