An adequate folic acid dose in pregnancy depends upon eating habits and whether a woman previously delivered a child with birth defects. A family history of children born with neural tube defects (NTD) might also determine folic acid dose in pregnancy. Research shows a link between folic acid dose in pregnancy and the number of babies born with abnormalities of the brain stem or spinal cord, collectively referred to as NTD. Women might not consume enough folic acid through food to protect an unborn child, especially if they adhere to a vegetarian diet.
Health agencies recommend all women of childbearing age who are capable of becoming pregnant should get at least 0.4 milligrams of folic acid each day. This level might not be possible by eating food rich in folate, the natural form of folic acid, because some people do not absorb this B vitamin properly. The recommended dosage might be achieved through fortified foods and vitamin supplements.
A woman who previously delivered a baby diagnosed with NTD might be advised to increase her folic acid dose in pregnancy up to 4 milligrams daily. Other amounts might be suggested by a doctor when birth defects run in the family, with each case considered on its own merits. Most prenatal vitamins contain between 0.4 and 0.8 milligrams of folic acid.
Studies on folic acid in high-risk pregnancies showed 4 milligrams a day of this vitamin reduced the number of babies born with neural tube defects by 70 percent. Daily supplements containing between 0.4 and 0.8 milligrams also lowered the risk for women who previously delivered healthy babies. The Centers for Disease Control advise total folate and folic acid consumption should not exceed 1 milligram a day unless recommended by a physician. Higher doses might complicate diagnosis of a vitamin B12 deficiency, which could cause other health problems.
Neural tube defects include spina bifida and anencephaly. Spina bifida occurs when tissue fails to grow over the spine before birth. Most children born with this condition live to adulthood, but typically suffer learning disabilities and some level of incontinence. Anencephaly happens when the brain stem and bones in the head fail to develop. Most babies born with this condition are stillborn or die soon after they are born.
An adequate folic acid dose in pregnancy might prevent these birth defects. Folic acid helps the body produce red blood cells and promotes the proper division of cells before birth. This vitamin is considered crucial before a woman conceives and during the first few weeks of pregnancy, often before a woman knows she is pregnant. Vitamin supplements and eating food high in folate, such as beef liver, chicken, beans, and some green vegetables, might protect a fetus. Some cereals, rice, and pasta are fortified with folic acid to help meet these nutritional needs.