Effect of oral contraceptives on Serum magnesium levels

Int J Fertil. 1974;19(4):224-6.


Serum magnesium levels were determined by atomic absorption apectrophotometry in 224 Nigerian women attending the post-partem Family Planning Clinic of University College Hospital, Ibadan. The concentrations of serum magnesium in 44 control subjects were similar to those of 87 women who had been fitted with the Lippes loop. Serum magnesium levels were significantly lower (P smaller than 0.001) in 28 women taking Ovral 28 and in 65 women taking Norlestrin Fe in comparison with the control group.

PIP: Considering the possibility that magnesium may be involved in the development of thromboembolism in humans, serum magnesium determinations were done in a group of 224 women attending the Post-Partum Family Planning Clinic of University College Hospital in Ibadan, Nigeria. Of these, 44 had been given no therapy, 87 had been fitted with Lippes loops, 28 were taking Ovral 28, and 65 were taking Norlestrin Fe. Those taking Ovral 28 had done so for an average of 9 months and those taking Norlestrin Fe, for 6 months. Magnesium concentrations were determined by atomic absorption spectrophotometry on serum deproteinized by a lanthanum-trichloroacetic acid diluent. Those fitted with Lippes loops had concentrations similar to the control group. Those taking the oral contraceptives had significantly lower levels (p less than .001) than the control group. Type of oral contraceptive or length of use was not correlated with serum magnesium levels. Results gave lower values than reported by others. In theory, the reduction in serum magnesium in women taking oral contraceptives would be associated with decreased clotting time and increased frequency of thromboembolic episodes.

MeSH terms

  • Adolescent
  • Adult
  • Contraceptives, Oral / pharmacology
  • Depression, Chemical
  • Ethinyl Estradiol / pharmacology*
  • Female
  • Humans
  • Intrauterine Devices
  • Magnesium / blood*
  • Middle Aged


  • Contraceptives, Oral
  • Ethinyl Estradiol
  • Magnesium