Largest Triplet Research Articles

The association of birth weight discordance and ponderal index in triplet gestations

AL INDEX IN TRIPLET GESTATIONS ROBIN B. KALISH, GEETA SHARMA, LOUIS G. KEITH, DEBBIE J. RHEA, ISAAC BLICKSTEIN, Weill Medical College of Cornell University, Obstetrics and Gynecology, New York, NY Northwestern University, Gynecology, Chicago, IL Matria Healthcare Inc., Department of Clinical Research, Marietta, GA Kaplan Medical Center, Obstetrics and Gynecology, Rehovot, Israel OBJECTIVE: Our objective was to determine the association of the ponderal index with birth weight discordance in triplets. STUDY DESIGN: We analyzed data from triplets delivered at 28-37 weeks for birth weight discordance (> 25%difference between the heaviest and lightest triplet). Three categories of discordance (low skew, symmetrical, and high skew) were classified according to the relative position of the middle triplet. Birth weights and the ponderal index (birth weight/length 3) of all concordant and discordant triplet groups were compared. RESULTS: Of 752 triplet sets included, 184 (24.5%) were discordant. Total triplet birth weight was higher in the concordant compared to all discordant categories. As opposed to birth weight, where only the middle triplet differed according to discordance pattern, the ponderal index for the largest triplet was significantly higher in the low skew discordant group compared to the concordant and other discordant triplet groups. In contrast, the ponderal indexes for the smallest and middle triplets were similar among the discordant groups. CONCLUSION: Discordance in triplet pregnancies exhibits different patterns of mass (birth weight) versus size (ponderal index). Our findings suggest that it may be the size of the largest triplet that determines the presence or absence of discordance in triplet gestations.

Birth weight discordance and adverse fetal and neonatal outcomes among triplets in the United States

Objective To examine the association between intratriplet birth weight discordance, fetal and neonatal mortality, and smallness for gestational age. Methods The 1995–1997 Centers for Disease Control and Prevention’s Matched Multiple Birth file was used for this analysis. Birth weight discordance was calculated as the difference in birth weight between the largest and the smallest triplet’s weight and expressed as percentage of the largest triplet’s weight. For the middle-weight triplet, we also used the largest triplet’s weight as a reference in calculating percentage birth weight discordance, which was then grouped into quintiles. Results Among 15,511 triplet live births and fetal deaths (at least 20 weeks’ gestation), 35% had less than 10% birth weight discordance, 19.3% had 10–15%, 16.4% had 15–21%, 15.2% had 21–29%, and 14.1% had 29% or more. After controlling for confounders, the risk of fetal death associated with quintile V was significantly higher than that associated with quintile I for smallest (odds ratio [OR] 10.88; 95% confidence interval [CI] 4.87, 26.56), middle (OR 22.6; 95% CI 11.05, 46.3), and largest (OR 2.41; 95% CI 1.01, 5.89) triplets. Smallest and middle triplets in quintile V were more likely than quintile I triplets to be born small for gestational age (OR 26.0; 95% CI 17.1, 39.9 for smallest, and OR 13.4; 95% CI 8.01, 22.3 for middle). Birth weight discordance quintile was not associated with smallness for geatational age among largest triplets nor consistently with neonatal mortality among smallest, middle, or largest triplets. Conclusion Increasing birth weight discordance was associated with increased risk of fetal death and smallness for gestational age. A birth weight discordance threshold of at least 29% should alert obstetricians for appropriate decision making.