Are vitamin C and zinc safe to use during pregnancy?

Safety of Vitamin C and Zinc in Pregnancy

Yes, both vitamin C and zinc are safe to use during pregnancy and are actually recommended as part of routine prenatal supplementation. 1

Zinc Safety and Recommendations

Zinc is considered safe in pregnancy and can be continued throughout pregnancy. 2 The evidence for zinc safety comes from multiple sources:

• Recommended supplementation dose is 8-15 mg per 1 mg of copper as part of standard prenatal care 1, 3
• A retrospective study of 136 women with Wilson's disease documented 282 pregnancies where 118 women were taking zinc throughout pregnancy with favorable maternal and fetal outcomes 2
• Zinc supplementation at therapeutic doses (30 mg/day) cannot be toxic during pregnancy 4
• Zinc plays a critical role in protein synthesis, nucleic acid metabolism, and cell division—all essential for fetal growth and development 4

Evidence on Zinc Efficacy

While zinc is safe, the evidence for routine supplementation benefits is mixed:

• A 2012 systematic review of 20 trials involving over 11,000 births found that zinc supplementation reduced the risk of preterm birth (relative risk 0.86,95% CI 0.75-0.99), though this evidence was graded as low quality 5
• No significant effects were demonstrated on birth weight, length at birth, or head circumference 5
• Zinc supplementation during pregnancy improved vitamin A status in both mothers and infants postpartum, indicating a specific role in vitamin A metabolism 6

Vitamin C Safety and Recommendations

Vitamin C supplementation is safe during pregnancy, though routine supplementation for all pregnant women is not strongly supported by evidence for preventing major pregnancy complications. 7

Safety Profile

• A comprehensive Cochrane review of 29 trials involving 24,300 women found no evidence of harm from vitamin C supplementation during pregnancy 7
• The only adverse effect noted was increased self-reported abdominal pain (RR 1.66,95% CI 1.16-2.37) in one study 7
• Pregnant women require an additional 10-20 mg/day of vitamin C beyond baseline requirements 2

Evidence on Vitamin C Efficacy

The evidence shows limited benefits for routine supplementation:

• No significant reduction in stillbirth, neonatal death, intrauterine growth restriction, preterm birth, or pre-eclampsia with vitamin C supplementation 7
• Vitamin C supplementation was associated with decreased risk of placental abruption (RR 0.64,95% CI 0.44-0.92) and a small increase in gestational age at birth 7
• When vitamin C was given alone (not combined with vitamin E), it reduced the risk of preterm prelabour rupture of membranes (PPROM) (RR 0.66,95% CI 0.48-0.91) 7

Important Caveats and Clinical Considerations

Avoid combining vitamin C with vitamin E during pregnancy, as this combination increased the risk of term PROM (RR 1.73,95% CI 1.34-2.23) 7

Both micronutrients should be part of a comprehensive prenatal vitamin regimen that includes folic acid, iron, calcium, and vitamin D 1, 3

For women with specific medical conditions:

• Women with Wilson's disease should continue zinc therapy throughout pregnancy with appropriate monitoring 2
• Women with BMI >30 kg/m² or diabetes require higher doses of other supplements (like folic acid at 4-5 mg daily) but standard zinc and vitamin C doses 1
• Women with history of bariatric surgery require more intensive monitoring and may need adjusted supplementation 1

Monitoring during pregnancy should include:

• Serum zinc levels as part of comprehensive micronutrient screening at least once per trimester for high-risk women 1
• No specific routine monitoring is required for vitamin C in uncomplicated pregnancies 2