Calcemia, Vitamin D and seasonal influences in preeclampsia in Goma

Background: The etiology of preeclampsia remains less well known. It is noted that low vitamin D levels are associated with a high risk of preeclampsia (PE). Calcium (Ca2+) levels during pregnancy appear to be involved in pregnancy-induced hypertension. Recent studies indicate that serum calcium levels may have a role in preeclampsia. Vitamin D promotes absorption of proper concentration of calcium in the blood which helps to lower blood pressure. The complications associated with calcium deficiency during a normal pregnancy are numerous and have not been extensively studied in Goma.

Objective: To assess blood calcium levels (ionic and total) in preeclamptic women and to analyse the seasonal influence on preeclampsia in Goma.

Method: A prospective case-control study (without matching) of 190 pregnant women without cardiovascular or endocrine diseases for a case-control ratio of 1∶1 was conducted in six hospitals in Goma. Blood ionogram was performed by an automated system directly after blood sampling and vitamin D was measured using enzyme-linked immunosorbent method.

Results: The mean ionised calcium level in preeclamptic woman was 1.24±0.16 mmol/L (0.48-1.59) compared to 1.27±0.17 mmol/L (0.88-2.30) in normal pregnant woman (p=0.214). A slight negative correlation between blood calcium and blood pressure was observed in pregnant women. Low vitamin D levels were associated with preeclampsia. Hypovitaminosis D in the preeclamptic group was more observed during the rainy season than during the dry season. Pregnancies complicated by PE were from fertilisations occurring during the rainy season while the dry season was characterised by a high admission of preeclamptics.

Conclusion: The study found that preeclamptic women in Goma had hypocalcemia. There was also a weak negative correlation between blood pressure and serum calcium levels. The majority of preeclamptics were diagnosed during the dry season, while conception with a PE complication occurred during the rainy season. As this is a first study in this area for the Great Lakes region of Africa, a more in-depth study with a larger sample size is desired.