Diet should be the primary source of vitamins and minerals, and women with multifetal pregnancies should consult with their health care providers about the special diets recommended for multifetal pregnancies. Several studies have shown that incorporating multivitamin-mineral supplementation into the care of women expecting twins and higher-order multiples can have a positive impact on the woman’s health and the pregnancy outcome. To date, there have been no vitamin-mineral supplementation studies with twin or higher-order multiple pregnancies.
It is known that women with multifetal pregnancies are at greater risk for vitamin and mineral deficiency, particularly of folic acid and iron. Deficiencies may occur because of the large and early increase in tissue mass for example, in blood volume, uterus, placenta, total fetal weight which usually occurs sooner than in a singleton pregnancy. A prenatal vitamins - mineral supplement will likely help women expecting twins and higher-order multiples achieve sufficient amounts of vital nutrients.
Currently, it is believed that the amount of supplemental folic acid recommended in multifetal pregnancies is the same as that for singleton pregnancies 600 µg daily. There is conflicting literature regarding whether or not folic acid taken periconceptionally before becoming pregnant is associated with increasing the chance of a multifetal pregnancy. The woman with her health care providers such as perinatologist, obstetrician, registered dietitian-nutritionist, and or medical internist should discuss the amount and timing of supplementation fully.