Role of Vitamin A in Pregnancy
Vitamin A plays essential roles in fetal development, vision, epithelial cell maintenance, immune function, reproduction, growth, and development during pregnancy, with both deficiency and excess posing significant risks to maternal and fetal outcomes. 1, 2
Functions of Vitamin A During Pregnancy
Vitamin A contributes to several critical processes during pregnancy:
- Fetal development: Essential for morphological and functional development of multiple organ systems 3
- Vision: Maintains ocular integrity and prevents night blindness 1, 3
- Cellular differentiation: Supports normal differentiation and maintenance of epithelial cells 1
- Immune function: Enhances T-cell function and overall immune response 1, 2
- Reproduction: Supports reproductive health and fetal growth 1
- Epigenetic regulation: Recently discovered to have important roles in fetal development through epigenetic mechanisms 1
Vitamin A Requirements in Pregnancy
Pregnancy increases vitamin A requirements due to:
- Active transfer of vitamin A to the developing fetus 1
- Hemodilution during pregnancy that can lower maternal vitamin A levels 1
- Increased metabolic demands of pregnancy 3
Most authorities recommend additional vitamin A intake during pregnancy:
- The American College of Obstetricians and Gynecologists recommends pregnant women avoid excess vitamin A (particularly in retinol form) and opt for beta-carotene forms 2
- Pregnant women should receive adequate vitamin A through diet or supplements in the form of beta-carotene 4
- The German Nutrition Society recommends a 40% increase in vitamin A intake for pregnant women 4
Risks of Vitamin A Imbalance
Vitamin A Deficiency
- Night blindness 3, 5
- Weakened immune function and increased susceptibility to infections 6
- Anemia 6
- Impaired fetal lung development and maturation 4
- Bone anomalies 5
- Epithelial cell problems 5
Vitamin A Excess
- Teratogenic effects, particularly in the first 60 days after conception 3, 5
- Central nervous system deformities 5
- Hypercalcemia 6
- Psychiatric symptoms 6
Sources and Supplementation
Food Sources
- Beta-carotene (provitamin A): Orange and dark green vegetables 4
- Fortified beverages: Represent 20-40% of daily supply 4
- Vitamin A-rich foods: Pregnant women are generally advised to avoid vitamin A-rich liver and liver foods 4
Supplementation Guidelines
- Beta-carotene is the essential source of vitamin A for pregnant women 4
- Routine prenatal vitamin A supplementation for prevention of maternal and infant morbidity is not universally recommended 3
- In regions where vitamin A deficiency is a public health issue, supplementation is recommended to prevent night blindness 3
- One tablet daily of beta-carotene with a meal is recommended before, during, and/or after pregnancy 7
Monitoring and Special Considerations
- Regular monitoring of vitamin A levels throughout pregnancy is recommended 2
- Vitamin A deficiency is more common in developing countries, while excess is more common in developed countries 5
- A clinical study showed almost 1/3 of women with short birth intervals or multiple births had plasma retinol levels below 1.4 μmol/l, indicating borderline deficiency 4
- Serum vitamin A levels vary throughout pregnancy, with deficiency being the main concern (24.98% of cases in one study) 8
- The rate of vitamin A deficiency was highest in early pregnancy (38.22%) compared to late pregnancy (35.13%) 8
Practical Recommendations
- Maintain balanced vitamin A intake during pregnancy through diet rich in beta-carotene sources
- Avoid excessive vitamin A supplementation, particularly in retinol form
- Consider beta-carotene supplementation if dietary intake is inadequate
- Regular monitoring of vitamin A status throughout pregnancy
- Consult healthcare provider for personalized recommendations based on individual risk factors
Maintaining optimal vitamin A status during pregnancy is crucial for maternal health and fetal development, with careful attention to avoiding both deficiency and excess.