Why are vitamins and minerals important for pregnant women?

Pregnant Women Need More Vitamins and Minerals Than Normal People

Because vitamins and minerals help nourish both the pregnant mother and the fetus, insufficient intake may directly harm the fetus. The important vitamins and minerals that pregnant women should receive include:

Iron supplement
Iron is very important during pregnancy because it is a key component of hemoglobin in red blood cells, which transports oxygen to the cells in both mother and fetus. The fetus continuously draws iron from the mother’s blood to produce its own red blood cells and prepares the mother’s body for blood loss during delivery. The recommended iron intake for pregnant women is about 60 mg/day. Doctors usually advise taking iron supplements (hematinic tablets) throughout pregnancy along with iron-rich foods such as liver, sesame, prunes, red meat, spinach, egg yolks, peas, red beans, and seaweed.

However, iron supplements may cause side effects such as nausea and vomiting, especially in the first 4 months of pregnancy (morning sickness). Absorption of iron in the digestive tract is inhibited by calcium and magnesium, so iron should not be taken together with antacids like antacid tablets.

If the mother has low hemoglobin levels, she may become anemic during pregnancy. Even mild blood loss during delivery can cause shock, leading to low birth weight, premature birth, and increased risk of death for both mother and baby.

Iodine
Iodine is crucial for fetal nervous system development. It helps reduce the risk of mental retardation and goiter in the fetus. Pregnant women need adequate iodine because thyroid gland activity increases 2-3 months into pregnancy, and iodine is lost through the kidneys. The required iodine intake is 175 micrograms/day. This amount can usually be obtained from eating seafood and sea salt in moderate amounts.

Excessive iodine intake, especially from large amounts of seafood or seaweed, can suppress the thyroid function of the fetus and cause fetal goiter. This can lead to mental retardation unrelated to genetic defects and other neurological abnormalities. The mother may also develop goiter.

Calcium
Calcium helps build the fetus’s bones and teeth. Adequate calcium intake preserves the mother’s bone density and reduces symptoms like muscle cramps related to muscle and vascular contractions. If the mother’s calcium intake is insufficient, her body will leach calcium from her bones to supply the fetus, which may cause osteoporosis, tooth decay, bone pain, and increase the risk of pregnancy complications such as preeclampsia or premature placental separation. The recommended calcium intake is 1,500 mg/day, equivalent to drinking 4 cartons of cow’s milk daily, preferably low-fat milk.

Calcium-rich foods include milk, yogurt, dried shrimp, sesame seeds, small dried fish, dark leafy greens, soy products, tofu, sardines (avoid canned), kale, broccoli, and oats. Excess calcium intake may cause poor absorption and lead to abdominal pain, bloating, and constipation, so it should be consumed in moderation.

Folic acid / Folate
Folate is important for the development of the nervous system and brain, formation of red blood cells, cell growth, and organ development. It also helps reduce birth defects. Insufficient folate before and during early pregnancy increases the risk of anemia in the mother and fetal birth defects such as skull and spinal abnormalities or spina bifida. Folate also reduces thalassemia (a blood disorder).

The recommended folate intake is about 550 micrograms/day. Doctors usually prescribe folate supplements starting at the first prenatal visit. Women planning pregnancy should begin folate supplements at least one month before conception and continue through the first three months of pregnancy.

Zinc
Zinc regulates cell function, especially cell division and wound healing in skin cells. Only about 1% of the body’s zinc is found in blood plasma, mostly bound to proteins and amino acids. Zinc deficiency may cause fetal growth retardation, low birth weight, and abnormal head circumference. It also slows wound healing in the mother.

Pregnant women should consume about 15 mg of zinc per day, which is typically adequate from a normal diet. Excess zinc intake has no reported abnormalities but may increase appetite loss.

Vitamin A
Vitamin A is important for fetal growth and development of systems such as nervous, heart, lungs, kidneys, eyes, reproductive organs, bones, and the immune system. It reduces maternal mortality and increases infant survival, anemia, and infection risks postpartum.

The required amount is 800 IU/day. Doctors typically prescribe vitamin A in tablet form. However, intake exceeding 10,000 IU/day, especially before 7 weeks gestation, may cause fetal skull and central nervous system abnormalities, including thymus gland issues. Vitamin A deficiency is rare since natural vegetables and fruits contain sufficient amounts. Excess vitamin A is generally not a concern due to limited absorption.

Vitamin C
Vitamin C helps build a strong placenta, reduces premature placental separation, allergy symptoms, and boosts immunity. It also aids iron absorption and acts as an antioxidant. The body needs daily vitamin C intake as it cannot be stored.

Pregnant women require about 70 mg/day (20% more than usual), which can be obtained from normal diet. Excess vitamin C may cause frequent colds, especially in those with allergies.

Energy and Protein
Protein and energy are very important during pregnancy for fetal organ development and maternal tissue repair. Pregnant women should gain about 10-15 kg in weight, including fetus, placenta, amniotic fluid, uterus, and breast tissue. The energy requirement is about 2,500 kcal/day, and protein about 60 grams/day (equivalent to half a chicken).

Eating excessive protein may cause the fetus to grow too large, increasing risks of premature labor, difficult delivery, or cesarean section. High maternal blood sugar during pregnancy can lead to gestational diabetes, causing the fetus to adapt to high glucose levels. After birth, this may result in hypoglycemia in the newborn, increased heart workload, abnormal body temperature, fetal growth retardation, premature birth, or fetal death.

Information provided by Professor Poonsak Suchonwanit