During pregnancy, women have increased nutritional requirements because both calories and nutrients (eg, folate, calcium, iron) are preferentially shunted to the developing fetus. To meet these metabolic demands, average women should increase their intake by approximately 350-450 kcal/day in the second and third trimesters.

During the initial prenatal visit, maternal nutrition should be discussed because certain foods and beverages may be harmful for fetal development. In addition, this provides a time to discuss optimal nutrition and common diet concerns, appropriate weight gain, and exercise.

Recommendations for weight gain in pregnancy depend on pre-pregnancy BMI, which is an indicator of baseline maternal fat and nutrient stores.

| Supplementation | • Daily prenatal vitamin • Additional specific supplements as indicated | | --- | --- | | Avoid harmful substances | • Substance abuse counseling • Avoidance of fish with high mercury levels • Moderate caffeine intake | | Food safety | • Avoid undercooked meat, fish & eggs • Clean raw fruits & vegetables • Avoid unpasteurized dairy products |

Lower the BMI requires greater gestational weight gain to maintain a healthy pregnancy.

Inadequate weight gain causes preterm delivery (which occurs when patients can no longer shunt enough nutrients to support the fetus) and low birth weight (ie, small for gestational age infant).

Women with a high prepregnancy BMI (eg, ≥30 kg/m2) and excessive gestational weight gain are at increased risk of cesarean delivery due to higher rates of gestational diabetes mellitus, fetal macrosomia, and labor dystocia.  Obesity also increases the risk of hypertension and preeclampsia due to increased systemic vascular resistance.

one of the causes of inadequate weight gain is Hyperemesis Gravidarum

THESE NUMBERS ARE FOR TERM

Nutrition in pregnancy is addressed at the initial prenatal visit.

• Appropriate weight gain: Women with a normal prepregnancy BMI (18.5-24.9 kg/m2) should gain 11.4-15.9 kg (25-35 lb) during pregnancy. This weight gain is equivalent to increasing caloric intake by 350 kcal/day during the second trimester and 450 kcal/day during the third. Patients following specific diets (eg, vegan) can continue the diet throughout pregnancy as long as it has well-balanced quantities of protein, carbohydrates, and fats (Choice B).
• Vitamin and mineral supplementation: A single, daily prenatal vitamin is recommended for the majority of pregnant women because it fulfills most of the daily vitamin and mineral supplementation requirements. Patients with vitamin or mineral deficiencies require specific supplementation (eg, iron) rather than multiple prenatal vitamins to avoid consuming harmful amounts of other vitamins (eg, vitamin A). Vegans, who are at risk for some vitamin and mineral deficiencies (eg, vitamin B12, calcium, iron) secondary to lack of meat consumption, may require supplementation.
• Avoidance of harmful substances: Patients are counseled on substance abuse (eg, alcohol) and substances to avoid in pregnancy (eg, fish with high mercury levels). Although high caffeine doses can be harmful during pregnancy, moderate intake (ie, 1 or 2 cups of coffee daily) is not.
• Safe handling of food: Some food products are associated with congenital infection and intrauterine fetal demise. Patients are counseled to avoid undercooked meat, fish, and eggs; to thoroughly clean raw fruits and vegetables; and to avoid unpasteurized dairy products.
• Probiotic (eg, Lactobacillus) intake during pregnancy may have some maternal benefits (eg, anti-inflammation, improved glucose metabolism), but data are limited.  However, most studies show no increased risk in adverse fetal outcomes, and patients may continue probiotic use if desired.

By maintaining proper maternal nutrition in pregnancy, patients provide appropriate fetal nutrition and decrease the risk of pregnancy complications (eg, low birth weight, preterm delivery).

Unlike adult anemia, which is commonly due to iron deficiency (eg, inadequate nutrition, blood loss), fetal anemia typically occurs due to fetal red blood cell destruction (ie, hemolysis). Common causes include Rh alloimmunization, which is caused by maternal autoantibodies against fetal red blood cells, and parvovirus B19 infection, which is cytotoxic to fetal red blood cell precursors.

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