Influence of birth weight on fetal cardiac indices at 35–37weeks' gestation

• Published in: Ultrasound in obstetrics & gynecology 2021-02, Vol.57 (2), p.266-272
• Main Authors: Semmler, J, S Abdel‐Azim, Anzoategui, S, Zhang, H, Nicolaides, K H, Charakida, M
• Format: Article
• Language: English
• Subjects: Birth weight; Cardiac function; Childbirth & labor; Continuity (mathematics); Diabetes mellitus; Eclampsia; Fetuses; Gestation; Gestational diabetes; Gynecology; Heart; Hypertension; Low-birth-weight; Morphology; Obstetrics; Oxygenation; Perfusion; Physiological responses; Physiology; Placenta; Population studies; Pregnancy; Regression analysis; Regression models; Ultrasonic imaging; Ultrasound; Uterus; Veins & arteries; Ventricle; Weight
• ISSN: 0960-7692; 1469-0705
• DOI: 10.1002/uog.23522

ObjectiveEchocardiographic studies have reported that fetuses with low birth weight, compared to those with normal birth weight, have globular hearts and reduced cardiac function. Dichotomizing continuous variables, such as birth weight, may be helpful in describing pathology in small studies but can prevent us from identifying physiological responses in relation to change in size. The aim of this study was to explore associations between fetal cardiac morphology and function and birth weight, as a continuous variable, as well as uterine artery (UtA) pulsatility index (PI), as an indirect measure of placental perfusion, and the cerebroplacental ratio (CPR), as an indirect measure of fetal oxygenation.MethodsThis was a prospective study of 1498 women with singleton pregnancy undergoing routine ultrasound examination at 35 + 0 to 36 + 6 weeks' gestation. Pregnancies complicated by pregestational or gestational diabetes mellitus, chronic hypertension, pregnancy‐induced hypertension or pre‐eclampsia were excluded from the analysis. Conventional and more advanced echocardiographic modalities, such as speckle tracking, were used to assess fetal cardiac function in the right and left ventricles. The morphology of the fetal heart was assessed by calculating the right and left sphericity indices. In addition, the PI of the UtA, umbilical artery (UA) and fetal middle cerebral artery (MCA) was determined and the CPR was calculated by dividing MCA‐PI by UA‐PI. Multiple linear regression models were used to assess determinants of fetal echocardiographic parameters.ResultsThe study population included 146 (9.7%) small‐for‐gestational‐age (SGA) fetuses with birth weight