OC18.05: Direct measurement of blood flow into the intervillous space and its relationship with the small for gestational age (SGA) baby
Year: 2010
Type: conference-abstract
Abstract: Inadequate transformation of the spiral arteries (SA) has long been implicated in adverse pregnancy outcomes (APO) such as pre-eclampsia and fetal growth restriction. Theoretical work suggests a pathological mechanism where the poorly converted SA's jet of blood into the intervillous space (IVS) causes mechanical destruction of the villi (the jet-hose effect). We investigated whether the flow of the jet into the IVS is different for small for gestational age (SGA) babies. With ethical approval, we prospectively recruited women with a singleton pregnancy to scans at 12, 14, 16, 18, 23, 28 & 33 weeks. Transabdominal 2D colour Doppler was used to identify the jets entering the IVS, we have previously shown that they can be measured precisely. The 3 most prominent jets were selected and their pulsatility index (PI) and resistance index (RI) measured. Uterine artery (UA) PI and RI were also measured. Customised birth weight centiles were calculated using the ‘Grow’ package, and SGA was defined as ⩽ 10 centile. A mixed model statistical analysis was used which takes into account the longitudinal nature of the data (SAS). 65 women were recruited. Nine women had SGA babies; only one had abnormal UA Dopplers at 23 weeks. Mixed model analysis demonstrated that the PI of the jets was significantly higher in ‘SGA’ pregnancies (P = 0.05) although the RI was not (P = 0.08). There was no significant difference in either the PI (P = 0.71) or RI (P = 0.84) of the UA between ‘SGA’ and ‘> 10 centile’ pregnancies. The PI of SA blood flow into the IVS is significantly higher when the pregnancy resulted in a SGA baby. Increased pulsatility may reflect the histologically observed persistence of vessel muscularity in the SA of pregnancies with APO. That no significant difference was seen in the UA indices may indicate that they are influenced by more than just physical change in the SAs. The technique used may have detected the pathology underlying impaired placentation resulting in SGA babies.
DOI: 10.1002/uog.7875
Institutions: John Radcliffe Hospital, University of Oxford
Language: English
Subfield: Obstetrics and Gynecology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2004770325