Effects of contraceptives on serum trace elements, calcium and phosphorus levels

Women on different contraceptive methods have been linked with the development of various diseases and possible changes in serum trace elements and vitamins of women on contraceptives have been postulated. Therefore, the relationship between contraceptive use and trace elements needs to be investigated.

This is a cross-sectional randomized study. After informed consent was obtained, blood samples were collected from a total of 100 women of child-bearing age on different contraceptive methods: 50 on oral contraceptives, 25 on injectables and another 25 on intra-uterine device. Blood samples were also collected from another 50 age-matched non-contraceptive users to serve as control. Serum was analysed using atomic absorption spectrophotometer for zinc, copper manganese, iron, selenium, cadmium, lead and magnesium while colorimetric method was used for phosphorus and calcium. Body mass index (BMI) was calculated as weight in kilogram/height in meter squared. Results obtained from laboratory analysis and anthropometric measurements were analysed using computer SPSS package.

The mean serum zinc, selenium, phosphorus and magnesium levels obtained from subjects on contraceptives were significantly lower (p < 0.01, p < 0.05, p < 0.05 and p < 0.05 respectively) than those of the control group. However, the mean serum copper iron, calcium and cadmium levels were significantly higher (p < 0.05) in participants on contraceptive when compared with the control group. Manganese and lead levels were similar in participants and control groups. Correlation analysis shows significant association between some trace elements and the duration of contraception and body mass index of the participants.

The study showed and confirmed reduced levels of trace elements in women on contraceptives. The reduction is proportional to the duration of contraceptive use.