Ponderal index (PI) vs birth weight centiles in the low-risk primigravid population: which is the better predictor of fetal wellbeing?

• Published in: Journal of obstetrics and gynaecology Vol. 32; no. 5; p. 439
• Main Authors: Cooley, S M, Donnelly, J C, Walsh, T, Kirkham, C, Gillan, J, Geary, M P
• Format: Journal Article
• Language: English
• Published: England 01.07.2012
• Subjects: Adult; Apgar Score; Birth Weight; Body Height; Body Mass Index; Body Weight; Female; Fetus - physiology; Gestational Age; Gravidity; Humans; Infant, Newborn; Placenta Diseases - diagnosis; Pregnancy; Pregnancy Outcome; Premature Birth; Prospective Studies; Risk Factors
• ISSN: 1364-6893
• DOI: 10.3109/01443615.2012.667172

Our objective was to compare Ponderal index (PI) with birth weight centiles as predictors of perinatal morbidity and to determine which best reflects the presence of placental disease. We prospectively recruited 1,011 low-risk primigravidas and calculated PI and birth weight centiles following delivery. Perinatal morbidity was defined as: pre-term birth (PTB); fetal acidosis; an Apgar score <7 at 5 min or neonatal resuscitation. Placental disease was defined as chronic uteroplacental insufficiency (CUPI); villous dysmaturity; infection or vascular pathology. Ponderal index was statistically reduced (25.33 vs 27.79 p =0.001) and the incidence of infant birth weight <9th centile was statistically higher (11.1% vs 5.1%; p =0.004) in cases with PTB and in CUPI (26.23 vs 27.84; p =0.001 and 28.2.1% vs 10.4%; p =0.002). Both PI and infant birth weight centile <9th centile for gestational age correlate with PTB, however overall, both are poor predictors of neonatal and placental disease.