Open AccessLow umbilical artery vascular flow resistance and fetal outcome
Author(s) -
Olofsson Per,
Olofsson Hanna,
Molin Johan,
Maršál Karel
Publication year - 2004
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.1111/j.0001-6349.2004.00339.x
Subject(s) - medicine , umbilical artery , mann–whitney u test , group b , exact test , apgar score , population , fetus , umbilical cord , pregnancy , obstetrics , gynecology , anatomy , genetics , environmental health , biology
Background. An abnormally high [above mean + 2 standard deviations (SD)] umbilical artery (UA) pulsatility index (PI) indicates impaired fetal outcome, whereas the impact of an “abnormally” low (below mean −2 SD) PI is unknown. Methods. Perinatal outcome was compared between cases with a UA PI less than mean −2 SD (group A: high‐risk cases selected from a database, n = 330; group B: unselected cases, n = 39) and unselected controls (group C) with a PI within mean ± 2 SD ( n = 863) at Doppler velocimetry. Groups B and C were retrieved from a population‐based sample. The unpaired t ‐test, Mann–Whitney U ‐test, χ 2 ‐test and Fisher's exact probability test were used for statistical comparisons with a two‐tailed p < 0.05 being significant. Results. No significant differences were found between group A vs. group C and group B vs. group C regarding perinatal mortality, Apgar scores at 1, 5 or 10 min, or arterial or venous cord blood pH. Postterm pregnancy in group A carried no additional risk. For obvious reasons, operative delivery and neonatal intensive care were more common in group A than in group C, but no such differences were found between groups B and C. The mean birthweight was 3.7% higher in group B than in group C ( p = 0.049). Conclusions. Deeming a UA PI below the lower reference limit as “abnormally” low is a statistical definition that was not reflected by a biological imperfection. Instead, a low UA PI promoted fetal growth.