Growth perturbations in a phenotype with rapid fetal growth preceding preterm labor and term birth.
The variability in fetal growth rates and gestation duration in humans is not well understood. Of interest are women presenting with an episode of preterm labor and subsequently delivering a term neonate, who is small relative to peers of similar gestational age. To further understand these relationships, fetal growth patterns predating an episode of preterm labor were investigated. Retrospective analysis of fetal biometry assessed by serial ultrasound in a prospectively studied sample of pregnancies in Santiago, Chile, tested the hypothesis that fetal growth patterns among uncomplicated pregnancies (n = 3,706) and those with an episode of preterm labor followed by term delivery (n = 184) were identical across the time intervals 16-22 weeks, 22-28 weeks, and 28-34 weeks in a multilevel mixed-effects regression. The hypothesis was not supported. Fetal weight growth rate was faster from 16 weeks among pregnancies with an episode of preterm labor (P < 0.05), declined across midgestation (22-28 weeks, P < 0.05), and rebounded between 28 and 34 weeks (P = 0.06). This was associated with perturbations in abdominal circumference growth and proportionately larger biparietal diameter from 22 gestational weeks (P = 0.03), greater femur (P = 0.01), biparietal diameter (P = 0.001) and head circumference (P = 0.02) dimensions relative to abdominal circumference across midgestation (22-28 weeks), followed by proportionately smaller femur diaphyseal length (P = 0.02) and biparietal diameter (P = 0.03) subsequently. A distinctive rapid growth phenotype characterized fetal growth preceding an episode of preterm labor among this sample of term-delivered neonates. Perturbations in abdominal circumference growth and patterns of proportionality suggest an altered growth strategy pre-dating the preterm labor episode.
Lampl
Michelle
M
Department of Anthropology, Emory University, Atlanta, Georgia, USA. mlampl@emory.edu
Kusanovic
Juan Pedro
JP
Erez
Offer
O
Gotsch
Francesca
F
Espinoza
Jimmy
J
Goncalves
Luis
L
Lee
Wesley
W
Gomez
Ricardo
R
Nien
Jyh Kae
JK
Frongillo
Edward A
EA
Romero
Roberto
R
D000328:Adult; D001699:Biometry; D015331:Cohort Studies; D005260:Female; D047109:Fetal Development; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age / Q000254:growth & development*; D007752:Obstetric Labor, Premature; D010641:Phenotype; D011247:Pregnancy; D012189:Retrospective Studies; D047929:Term Birth; D016216:Ultrasonography, Prenatal; D055815:Young Adult