Assessing blood flow chracteristics across the foramen ovale in term infants during transition at birth: an observational study.

Directly after birth, major cardiovascular changes occur during transition from
intra-uterine to extra-uterine life. Normally, the cardiovascular adaptation
during transition to life occurs uneventful without any hemodynamic compromise.
The pulmonary and circulatory transition are intimately linked and lung
aeration is the master switch for increase in pulmonary blood flow. Recent data
has shown that the direction of flow over fetal shunts (ductus arteriosus (DA),
ductus venosus, foramen ovale) play a vital role during these crucial changes.1
During the increase in pulmonary blood flow concomitantly a reversal of ductal
shunt occurs, leading to a short circuit circulation (pulmonary artery-left
heart-aorta-pulmonary artery). Research has shown in healthy term newborns flow
changes over the DA from predominantly right-to-left shunting to predominantly
left-to-right shunting at 10 minutes after birth, contributing to this short
circuit.2 It is speculated that this temporarily short circuit provides
acclimating time for the heart to get adapted to the hemodynamic changes. This
short circuit most likely will lead to a more predominant left to right shunt
over the FO. However, there is very little data on the behavior of the shunt
over the FO and how this relates to cord clamping. In addition, recent data
demonstrated that blood flow over the ductus venosus increases during
inspiration.3 While it is generally believed that this could potentially result
in an elevation of right ventricular preload, its occurrence would hinge on the
direction of the shunt through the FO and its role in augmenting pulmonary
circulation. Consequently, gaining insight into the flow of blood through the
FO during the transitional phase would enable us to define the most favorable
moment for umbilical cord clamping from a hemodynamic perspective.
Understanding the cardio-physiological changes that occur during transition
from intrauterine to extrauterine life and adverse adaptation are crucial for
healthcare providers caring for neonates. Therefore we aim to investigate blood
flow patterns through the FO in healthy full-term infants directly after birth
and determine how this is influenced by breathing and cord clamping.

The aims of this study are [1]. to investigate the flow hemodynamics through
the foramen ovale (FO) directly after birth and [2]. to assess how these
changes are influenced by breathing and the timing of umbilical cord clamping
in healthy term infants.

Primary Objective: To assess the cardiovascular changes and blood flow
hemodynamics through the FO in term infants immediately after birth, utilizing
transthoracic ultrasound.

Secondary Objective(s): To evaluate the effect of breathing and the timing of
umbilical cord clamping on the flow hemodynamics across the FO during the
critical transition from fetal to neonatal circulation.

We will perform a single center prospective observational study in healthy
full-term infants at the Department of Obstetrics and Neonatology of the Leiden
University Medical Center (LUMC). The observational nature of the study allows
us to capture real-time data without interventions that might affect the
physiological processes directly after birth.

There are no benefits to this study. A possible risk could be the chance of
interference between mother-child bonding whilst obtaining ultrasonography
measurements. Although this has not been previously studied, we recently
performed similar studies where the ultrasonography did not interfere with the
first bonding.2,3 It was not necessary to stop the procedure in any of the
occasions and the feedback of the parents was positive. Conform standard, the
infants will be placed immediately on the mother*s chest. Also, we will only
approach multigravida mothers. Group relatedness of this study is based on the
measurement taken whilst the child is still attached to the umbilical cord and
measurements directly after umbilical cord clamping.