Singleton birthweight by gestational age following in vitro fertilization in the United States.
BACKGROUND
Assisted reproductive technology has been reported to account for a disproportionate higher number of low birthweight infants, even in singleton births. Low birthweight infants occur from preterm birth, decreased intrauterine growth, or both. It is unclear whether infants conceived by in vitro fertilization (IVF) have a reduced intrauterine growth rate or intrauterine growth restriction. Growth-restricted newborns have higher perinatal morbidity and are at increased risk for adult-onset illnesses. To date, there are no national standards for birthweight percentiles by gestational week, allowing for fetal growth assessment of singletons conceived by assisted reproductive technology in the United States.


OBJECTIVE
The objective of the study was to establish US singleton IVF reference standards using birthweight percentiles by gestational age for singleton live births resulting from IVF in the United States.


METHODS
We studied birthweight by completed weeks of gestation for 93,443 singleton IVF births reported to the Society for Assisted Reproductive Technologies, 2006-2010. The third to 97th birthweight percentiles per completed week of gestation for weeks between 24 and 42 were calculated and were compared with recently published birthweight percentiles by gestational age for 3,812,730 US singleton births in 2011.


RESULTS
Smoothed birthweight for gestational age charts and curves were created for all US IVF singletons and female-male singletons from 24 to 42 weeks. Over the span of 31-41 weeks of gestation, the 10th, 50th, and 90th birthweight percentile values of IVF singletons were comparable with recently published birthweight percentile values of US singletons. At 40 completed weeks of gestation, the 10th, 50th, and 90th birthweight percentiles of all IVF singletons were 3078, 3506, and 4053 g, as compared with corresponding 3005, 3499, and 4057 g of US singletons. The 10th, 50th, and 90th birthweight percentile values for female and male IVF singletons were also comparable with US female and male singletons.


CONCLUSIONS
Birthweight percentiles per completed week of gestation of IVF and US singletons are approximately equal from 31 until 41 completed weeks, suggesting that intrauterine growth is not reduced in IVF singleton infants.
Section of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Louisiana State University School of Medicine, New Orleans, LA; The Fertility Institute of New Orleans, New Orleans, LA. Electronic address: finooo@charter.net.
Richard P
RP
Dickey
Department of Epidemiology, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA.
Xu
X
Xiong
Department of Obstetrics and Gynecology, Tulane University, New Orleans, LA.
Gabriella
G
Pridjian
The Fertility Institute of New Orleans, New Orleans, LA.
Monica C
MC
Klempel
D000328:Adult; D001724:Birth Weight; D005260:Female; D005307:Fertilization in Vitro; D047109:Fetal Development; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D012016:Reference Values; D014481:United States
birthweight; female; gestational age; in vitro fertilization; male; singleton