Early adequate maternal weight gain is associated with fewer small for gestational age triplets

Objective: To examine whether the recommended weight gain during the first 24 weeks reduces the frequency of SGA triplets. Study design: We used data collected by the Women's Health Division of Matria Healthcare, Inc (Marietta, GA). We studied the frequency of SGA triplets (birth weight <10^th percentile by triplet standards) by weight gain, parity, and pregravid BMI category. Adequate weight gain was defined as >16.2 kg at 24 weeks and BMI categories were defined as underweight (<19.8), normal (19.8-26), and obese (BMI>26). Results: We studied 2890 triplet sets. Adequate weight gain reduces the frequency of SGA triplets, irrespective of pregravid BMI category and parity, except for obese nulliparous women. However, the reduced frequency of SGA infants was significant only in underweight nulliparas (OR 0.3, 95% CI 0.1, 0.9). Conclusion: Higher pregravid BMI and parity seem to reduce the occurrence of SGA triplets. However, lean mothers, especially nulliparas, may be the most important target population for nutritional intervention in triplet pregnancies.