Pregnancy and the Use of Nutritional Supplements - Women's Health Update

Townsend Letter for Doctors and Patients,  Jan, 2002  by Tori Hudson

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Pregnancy and birthing are normal physiological processes that can be positively supported through adequate rest, preventive nutrition, and the avoidance of harmful substances. Minimizing stress, getting plenty of low-impact exercise and fresh air, and sleeping well are important factors leading to a positive overall experience of pregnancy and birth. The important thing to remember is that each pregnancy is unique, and although there are certain universal factors to consider, the most important preventive medicine is the mother's own relationship to her body and her emotional and physical connection to the child she is carrying.

During pregnancy hormone secretion changes radically, causing the physical and emotional changes experienced by most women fairly early in the first trimester. Estrogen and progesterone levels are about 100 times higher than usual during pregnancy, dropping immediately after birth to prepregnancy levels, as prolactin (the pituitary hormone) is produced to stimulate the production of breast milk. Throughout pregnancy the placenta produces a hormone called relaxin, which softens the connective tissues and ligaments that support the uterus, allowing it to expand. The production of endorphins (morphine-like hormones that are the body's natural painkillers and tranquilizers) is increased during pregnancy and continues to rise during labor when it reaches peak levels. (1) These hormonal changes can lead to the experience of "morning sickness" or nausea in the first trimester, especially when there are nutritional deficiencies as well.

Nearly all pregnant women can benefit from nutritional and multivitamin supplementation one year before and all during pregnancy, and throughout labor, delivery, and breast-feeding. The effects of poor nutrition during pregnancy can be seen in the increase of birth defects during times of famine. (2) But a standard Western diet (high in fats, salt, sugar, and low in complex carbohydrates) also lacks necessary essential vitamins and minerals needed during pregnancy and breast-feeding, leading to a "compromise in an offspring's health." (3) The appropriate diet is well-balanced and varied, and includes fresh fruits, vegetables, whole grains, legumes, beans and fish, with a limit on refined sugars, processed foods, and saturated fats. Organically grown produce, meats, and poultry are preferable, or at least carefully washed produce to remove agricultural chemicals. (4)

In an observational study involving 76 healthy pregnant women, 78% had "one or more glaring nutritional deficiency." (5) Another study showed an "overall apparent protective effect of pen-conceptual multivitamin use" for prevention of certain pregnancy-related illnesses and birth defects. (6) Of especial importance are folate (folic acid) and calcium intake, since the requirement for both of these substances (one a vitamin, the other a mineral) doubles during pregnancy.

"The fetus, the neonate, and the pregnant woman have an increased requirement for folic acid and vitamin B12, and are more likely to suffer from a deficiency of these vitamins." (7) Nutrients such as folic acid, vitamin B6 and B12 all have been correlated with prevention of the more common negative pregnancy outcomes, such as spontaneous abortion, placental abruption, pre-term delivery, low infant birth weight, and neural tube defects (e.g. spina bifida and anencephaly). (8) Supplementation with calcium, the only mineral whose requirement doubles during pregnancy, (9) has been positively correlated with prevention of pregnancy hypertension (10) and preeclampsia, (11,12) preterm delivery, (13) and low birth weight, (14) as well as puerperal psychosis (postpartum depression). (15) Magnesium supplementation has also been shown in studies to reduce the complications of pregnancy and improve the health of the infant. (16)

Nutritional Supplements

Folic Acid

Folate is the only vitamin, whose requirement doubles in pregnancy. (17) Deficiencies of folic acid have been linked in studies to low birth weight infants and neural tube defects. According to one controlled study, women at high risk (having previously given birth to babies with neural tube defects) given folate supplementation, showed a 72% protective effect compared to the placebo group. (18) In one study, a group of pregnant women given folate supplementation gave birth to infants with increased birth weight and Apgar scores, and had a decreased incidence of fetal growth retardation and maternal infections. (19) Other studies also showed significant prevention with supplementation. (20-23) Because of firmly-established connections between deficiencies of folic acid and low birth weight infants and neural tube defects, the US Public Health Service recommends that all women of childbearing age take daily folic acid supplementation to reduce their risk of congenital birth defects.

Dietary folic acid is a mixture of folates in the form of polyglutamates, which are readily destroyed by cooking. Higher levels of dietary folate intake has been shown in some cases to decrease the incidence of neural tube defects, but women hereditarily predisposed to such defects may need to take in more folic acid through supplements in order to reach optimal levels. (24) Folic acid can be found in green leafy vegetables, nuts and whole grains, liver, watercress, parsley, and dandelion. With artificial supplementation, care must be taken, because large doses of folic acid have been associated with a decrease in zinc absorption, a mineral required for proper fetal growth and immunity, (25) as well as maternal infection and abnormally slow fetal heart rate. (26)