Birth weight in a large series of triplets

Abstract

BackgroundTriplets are often born premature and with a low birth weight. Because the incidence of triplet births is rare, there are relatively few studies describing triplet birth weight characteristics. Earlier studies are often characterized by small sample sizes and lack information on important background variables such as zygosity. The objective of this study is to examine factors associated with birth weight in a large, population-based sample of triplets registered with the Netherlands Twin Register (NTR).MethodsIn a sample of 1230 triplets from 410 families, the effects of assisted reproductive techniques, zygosity, birth order, gestational age, sex, maternal smoking and alcohol consumption during pregnancy on birth weight were assessed. The resemblance among triplets for birth weight was estimated as a function of zygosity. Birth weight discordance within families was studied by the pair-wise difference between triplets, expressed as a percentage of the birth weight of the heaviest child. We compare data from triplets registered with the NTR with data from population records, which include live births, stillbirths and children that have deceased within days after birth.ResultsThere was no effect of assisted reproductive techniques on triplet birth weight. At gestational age 24 to 40 weeks triplets gained on average 130 grams per week; boys weighed 110 grams more than girls and triplets of smoking mothers weighted 104 grams less than children of non-smoking mothers. Monozygotic triplets had lower birth weights than di- and trizygotic triplets and birth weight discordance was smaller in monozygotic triplets than in di- and trizygotic triplets. The correlation in birth weight among monozygotic and dizygotic triplets was 0.42 and 0.32, respectively. In nearly two-thirds of the families, the heaviest and the lightest triplet had a birth weight discordance over 15%. The NTR sample is representative for the Dutch triplet population that is still alive 28 days after birth.ConclusionBirth weight is an important determinant of childhood development. Triplet status, gestational age, sex, zygosity and maternal smoking affect birth weight. The combined effects amount to a difference of 364 grams between monozygotic girl triplets of smoking mothers compared to dizygotic boy triplets of non-smoking mothers of the same gestational age. Birth weight in triplets is also influenced by genetic factors, as indicated by a larger correlation in monozygotic than in di- and trizygotic triplets.

Study of a Population of Triplet Pregnancies: Maternal and Neonatal Outcomes

“…The optimal gestational age at birth for triplet pregnancies is reported to be 34-35 weeks, at a weight of 1,900-2,200 g [19]. The mean gestational age at delivery in our study was 31.8 weeks, with a mean birth weight of 1590 g. These values are comparable with data in the literature [20][21][22][23][24].…”

Effects of Chorionicity and Zygosity on Triplet Birth Weight

“…In 2008, all mothers of triplets received the second NTR survey, Questionnaire 2 (Q2). Q1; Q2 included items about the triplet pregnancy, birth, and additional triplet characteristics (Lamb et al, 2011).…”

Weight Growth of Triplet Infants From Birth to Twelve Years of Age

“…However, since the mothers reported the growth of their children retrospectively based on records, there is no age-related dropout in our data. Data on zygosity, maternal smoking, previous obstetric outcome, and maternal weight gain during pregnancy are also lacking in this study, and it has been suggested that these factors are associated with weight growth (Lamb et al, 2011;Luke et al, 2002;Ooki & Yokoyama, 2003;Vogazianos et al, 2005).…”