Calcium supplementation may prevent pre-eclampsia risk, study finds

Canada: In women who consume little calcium, both low- and high-dose calcium supplements are useful in preventing pre-eclampsia, says an article published in the BJOG journal. 

Pre-eclampsia risk is decreased by calcium supplementation, although there are still unanswered problems regarding the ideal dosage and target population. In order to determine the effectiveness of high (1 g/day) and low (1 g/day) calcium doses for the prevention of pre-eclampsia, as per baseline pre-eclampsia risk, dietary calcium, co-interventions, and intervention timing, Mai-Lei Woo Kinshella and colleagues performed this study.

Randomized controlled studies of calcium supplementation for women before or during pregnancy to prevent pre-eclampsia were taken into account. Trials using various calcium dosages were also included in the network meta-analysis (NMA). Published data were retrieved by two impartial reviewers. To evaluate the direct and indirect effects, the meta-analysis used random-effects models and the NMA, a Bayesian random-effects model.

The key findings of this study were as follows:

1. The NMA to assess calcium dose comprised 25 trials (N = 15 038), whereas the meta-analysis included 30 trials (N = 20 445 women).

2. Pre-eclampsia was avoided by calcium supplementation equally well at high and low doses.

3. By NMA, the effects of high-dose (vs. low-dose) calcium were the same.

4. Regardless of baseline pre-eclampsia risk, vitamin D co-administration, or time of calcium beginning, calcium was equally efficacious.

5. However, calcium was ineffective in women who had appropriate baseline calcium consumption.

In conclusion, in LMICs and high-income nations, calcium consumption should be monitored both at the population level and individually for women who have low calcium intake. In women with poor calcium consumption, calcium is equally effective at lowering both preterm and term pre-eclampsia. Calcium is a complementary therapy to early multi-factor screening and aspirin usage, which prevent 60% of preterm pre-eclampsia but not the 70% of illness that emerges at term. Future studies should concentrate on the best ways to identify and target women with poor calcium consumption for individualized pre-eclampsia prevention in the second half of pregnancy, both where the average calcium intake is low and where it is not.

Reference: 

Woo Kinshella, M., Sarr, C., Sandhu, A., Bone, J. N., Vidler, M., Moore, S. E., Elango, R., Cormick, G., Belizan, J. M., Hofmeyr, G. J., Magee, L. A., & von Dadelszen, P. (2022). Calcium for pre‐eclampsia prevention: A systematic review and network meta‐analysis to guide personalised antenatal care. In BJOG: An International Journal of Obstetrics & Gynaecology. Wiley. https://doi.org/10.1111/1471-0528.17222