Vitamin B6, which is pyridoxine, does not require supple mentation in most gravidas (Salam, 2015). For women at high risk for inadequate nutrition, a daily 2-mg supplement is rec ommended. As discussed on page 174, vitamin B6, when com bined with the antihistamine doxylamine, is helpful in many cases of nausea and vomiting of pregnancy.
Vitamin C allowances during pregnancy are 80 to 85 mg/ d
Table 9-5). A reasonable diet should readily provide this amount, and supplementation is not necessary (Rumbold, 2015). Maternal plasma levels decline during pregnancy, whereas cord-blood levels are higher, a phenomenon observed with most water-soluble vitamins.
Vitamin D is a fat-soluble vitamin. After being metabolized to its active form, it boosts the eiciency of intestinal calcium absorption and promotes bone mineralization and growth. Unlike most vitamins that are obtained exclusively from dietary intake, vitamin D is also synthesized endogenously with exposure to sunlight. Vitamin D deiciency is common during pregnancy. his is especially true in high-risk groups such as women with limited sun exposure, vegetarians, and ethnic minoritiesparticularly those with darker skin (Bodnar, 2007). Maternal deiciency can cause disordered skeletal homeostasis, congenital rickets, and fractures in the newborn (American College of Obstetricians and Gynecologists, 2017k). Vitamin D supplementation to women with asthma may decrease the likelihood of childhood asthma in their fetuses (Litonjua, 2016). The Food and Nutrition Board of the Institute of Medicine (2011) established that an adequate intake of vitamin D during pregnancy and lactation was 15 �g/d (600 IU/d). In women suspected of having vitamin D deficiency, serum levels of 25-hydroxyvitamin D can be obtained. Even then, the optimal levels in pregnancy have not been established (De-Regil, 2016).
Although researchers continue to study the ideal nutritional regimen for the pregnant woman and her fetus, basic tenets for the clinician include: 1.
Advise the pregnant woman to eat food types she wants in reasonable amounts and salted to taste.
2.
Ensure that food is amply available for socioeconomically deprived women.
3.
Monitor weight gain, with a goal of approximately 25 to 35elb in women with a normal BMI.
4.
Explore food intake by dietary recall periodically to discover the occasional nutritionally errant diet.
5.
Give tablets of simple iron salts that provide at least 27 mg of elemental iron daily. Give folate supplementation before and in the early weeks of pregnancy. Provide iodine supplementation in areas of known dietary insuiciency.
6.
Recheck the hematocrit or hemoglobin concentration at 28 to 32 weeks' gestation to detect signiicant anemia.
TABLE 9-6. Some Contraindications to Exercise During Pregnancy
Significant cardiovascular or pulmonary disease Significant risk for preterm labor: cerclage, multifetal gestation, significant bleeding, threatened preterm labor, prematurely ruptured membranes Obstetrical complications: preeclampsia, placenta previa, poorly controlled diabetes or epilepsy, morbid obesity,
Summarized from American College of Obstetricians and Gynecologists, 2017g.