The association between fetal and neonatal circulation in preterm born intrauterine growth restricted infants.

Schmitz, D.M. (2014) The association between fetal and neonatal circulation in preterm born intrauterine growth restricted infants. thesis, Medicine.

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Abstract

Background: Intrauterine growth restriction (IUGR) is a condition where a fetus fails to reach its intrinsic growth potential in utero. It is a common complication during pregnancy and occurs in both preterm and full term infants. In IUGR infants, redistribution of the fetal blood to the vital organs represents a compensatory mechanism to prevent fetal damage, indicating a relative sparing of the growth of the fetal head in a suboptimal environment. This may have important effects on both fetal and neonatal circulation. It is unknown whether neonatal circulation is still affected by IUGR. Objective: To determine the associations between fetal Doppler ultrasound measurements and the neonatal circulation in preterm born IUGR infants during the first 5 days after birth. Our second aim was to compare whether the associations between fetal blood flow patterns and postnatal distribution of the oxygenation differed between preterm and term IUGR infants. Methods: During pregnancy, IUGR fetuses were considered for inclusion if they had an abdominal circumference below the 10th percentile or a deflecting growth. Mothers were monitored at the Department of Obstetrics and Gynecology in the UMCG between May 2012 and April 2014. The parents received information about the study and decided whether they wanted to join. Prenatally, flow patterns of IUGR fetuses were measured by Doppler ultrasound. Pulsatility indices (PI) of the umbilical artery, middle cerebral artery, and ductus venosus were determined weekly. Only the last measurement before birth was used for analyses. After birth, we included IUGR infants (<42 weeks gestational age) whose parents gave written informed consent. We included only live-born neonates and singleton pregnancies, and excluded fetuses or infants with chromosomal or syndromal abnormalities and congenital infections. We performed multisite near-infrared spectroscopy (NIRS) measurements 2 hours per day continuously in the first 5 days of life. NIRS values were used as outcome measures; cerebral, renal and abdominal tissue oxygen saturation (rSO2), transcutaneous SO2 (SpO2), and fractional tissue oxygen extraction (FTOE = (SpO2 - rSO2) /SpO2). Correlation coefficients (Spearman’s ρ) between z-score of the last PI measurements before birth and NIRS measurements after birth on different days were calculated. In a previous study we calculated correlation coefficients in term IUGR infants. Results: We included 42 IUGR infants (21 preterm/21 term born), with a median gestational age of 31.3 weeks (interquartile range IQR 28.5–33.2), and 38.6 weeks (IQR 37.7–39.1), respectively. The median birth weight in preterm infants was 1100 grams (IQR 770–1510), in term infants 2420 grams (IQR 2027–2645). In preterm born IUGR infants we found the strongest positive association between the PI umbilical artery and the abdominal FTOE (ρ = 0.747, p = 0.008), and the strongest negative association between the PI umbilical artery and the ratio cerebral FTOE /abdominal FTOE (ρ = -0.764, p = 0.006 ), both on day 1. No associations were found between fetal blood flow patterns and cerebral rSO2 and FTOE in preterm infants. Our second aim was to compare preterm and term infants. In preterm infants we found lower cerebral FTOE on days 1 and 2 (p = 0.030, p = 0.002, respectively). Median z-score of PI umbilical artery was higher in the preterm group (p = 0.014), the PI middle cerebral artery was lower in the preterm group (p = 0.001). Conclusion: Our findings demonstrated associations between the PI umbilical artery and NIRS measurements of the renal and abdominal region after birth in IUGR infants. We explained most associations by altered neonatal circulation in IUGR infants. Cerebral FTOE was lower in preterm infants, compared to term infants. The difference vanished after 2 days. This may indicate that preterm born IUGR infants experience brain sparing after birth, whereas term born IUGR infants do not.

Item Type:	Thesis (Thesis)
Supervisor name:	Bos, Prof. Dr. A.F.
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 11:07
Last Modified:	25 Jun 2020 11:07
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/2690

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