Michigan State University, East Lansing, Estados Unidos de América
Introduction: The multiple birth rate has increased dramatically in recent decades, due to a delay in childbearing and the increased use of infertility treatments. Infants of multiple births are at greatly increased risk for adverse perinatal outcomes, including prematurity, low birthweight, and growth restriction, as well as long-term perinatally-related health sequelae. Body: Four factors have been shown to result in the best improvements in multiple births: increasing length of gestation, increasing the rate of intrauterine growth, improving maternal nutritional status, and enhancing prenatal care. For twins, optimal length of gestation is 37-39 weeks (1); twins born at this gestation average 30-35% greater rate of fetal growth than twins born at less than 32 weeks (2); BMI-specific weight gain guidelines have been shown to improve length of gestation, birthweight, and birthweight-forgestation (3, 4); and a specialized program of prenatal care is associated with improved outcomes in multiple gestations, including reduced maternal and infant morbidity and healthcare costs (5). The use of diabetic-based diet regimen of at least 3,500 calories/day for twins, as 20% of calories from protein, 30-40% of calories from fat, and 40-50% of calories from carbohydrate has been shown to be therapeutic in terms of improving fetal growth, length of gestation, and reducing maternal and infant complications. Weight gain guidelines for underweight, normal weight, overweight, and obese women, targeted at 20 weeks, 28 weeks, and 38 weeks, have also been shown to be associated with longer length of gestation, higher birthweights, and reduced complications. These guidelines were adopted in 2009 by the Institute of Medicine as the first national weight gain guidelines for twin pregnancies in the United States. Conclusions: Perinatal outcomes in multiple pregnancies can be greatly improved through nutritional and prenatal care interventions, target to maternal BMI status and plurality. References: 1. Luke B, Brown MB, Alexandre PK, Kinoshi T, O’Sullivan MJ, Martin D, Misiunas RB, Nugent C, van de Ven C, Newman RB, Mauldin JG, Witter FR. The cost of twin pregnancy: Maternal and neonatal factors. Am J Obstet Gynecol 2005; 192:909-15. 2. Hediger ML, Luke B, Gonzalez-Quintero VH, Witter FR, Mauldin J, Newman RB. Fetal growth rates and very preterm birth of twins. Am J Obstet Gynecol 2005; 193:1498-507. 3. Luke B, Min S-J, Gillespie B, Avni M, Witter FR, Newman RB, Mauldin JG, Salman AF, O’Sullivan MJ. The importance of early weight gain on the intrauterine growth and birthweight of twins. Am J Obstet Gynecol 1998; 179(5):1155-61. 4. Luke B, Hediger ML, Nugent C, Newman RB, Mauldin JG, Witter FR, O’Sullivan MJ. Body mass index-specific weight gains associated with optimal birth weights in twin pregnancies. J Reproductive Med 2003; 48:217-224. 5. Luke B, Brown MB, Misiunas R, Anderson E, Nugent C, van de Ven C, Burpee B, Gogliotti S. Specialized prenatal care and maternal and infant outcomes in twin pregnancy. Am J Obstet Gynecol 2003; 189:934-8.