Thyroid functions of women taking oral contraceptives

Contraception. 1974 Mar;9(3):305-14. doi: 10.1016/0010-7824(74)90021-3.


PIP: A study to assess thyroid status and excessive weight gain among women taking oral contraceptives found a correlation between the percentage of free thyroxine and weight gain. Serum percentage of iodine uptake, total thyroxine, free thoraxine, and weight changes in 38 women taking combination oral contraceptives and 27 taking low dosage progestagens were studied. No change in the absolute free thyroxine levels were observed, although combination oral contraceptives caused an increase in total thyroxine and a decrease in the percentage of free thyroxine. Changes occurring in percentage of free and total thyroxine could be related to increases in thyroxine binding proteins. Low dosage progestogens showed no change in any of the thyroid tests studied. A lowering of the 24-hour uptake by the thyroid gland and weight gain with combination oral contraceptives were observed.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Body Weight
  • Contraceptive Devices
  • Contraceptives, Oral / pharmacology*
  • Drug Combinations
  • Ethinyl Estradiol / pharmacology
  • Female
  • Humans
  • Iodine Radioisotopes / metabolism
  • Megestrol / pharmacology
  • Norgestrel / pharmacology
  • Parity
  • Thyroid Function Tests
  • Thyroid Gland / drug effects*
  • Thyroid Gland / metabolism
  • Thyroxine / blood


  • Contraceptives, Oral
  • Drug Combinations
  • Iodine Radioisotopes
  • Norgestrel
  • Ethinyl Estradiol
  • Megestrol
  • Thyroxine