ReviewObstetricsIntrauterine growth restriction: new concepts in antenatal surveillance, diagnosis, and management
Section snippets
New tools and new insights
In modern epidemiological research, the standard for birthweight for gestation has been refined to be able to assess birthweight not against the average of the population but against an individual growth potential calculated for each baby in each pregnancy.
This is based on 3 principles.6, 7 First, the standard is adjusted or customized for sex as well as maternal characteristics such as height, weight, parity, and ethnic origin on the principle that one size does not fit all.8 The stepwise
Previous history of growth restriction or stillbirth
Women with a previous growth-restricted baby have a 50% increased risk of severe growth restriction in the current pregnancy,27 and serial third-trimester assessment for this indication is common practice. A history of stillbirth is also an accepted indication for intensive antepartum surveillance because more than half of normally formed stillbirths are associated with IUGR.22 Stillbirths before 32 weeks' gestation have a particularly strong association with IUGR.28 Previous stillbirth would
Diagnosis of IUGR
Current thinking on the natural history of growth restriction differentiates between early-onset and late-onset forms,100 which have different biochemical, histological, and clinical features.101 Whereas the former is usually diagnosed with an abnormal umbilical artery Doppler and is frequently associated with preeclampsia, the latter is more prevalent, shows less change in umbilical flow pattern, and has a weaker association with preeclampsia.101
Assessment of the IUGR fetus
Because no treatment has been demonstrated to be of benefit for FGR,124, 125, 126, 127 the assessment of fetal well-being and timely delivery remains as the main strategy for management. Fetal well-being tests could be classified as chronic or acute. Whereas, the former becomes progressively abnormal because of increasing hypoxemia and/or hypoxia, the latter correlates with acute changes occurring in advanced stages of fetal compromise, characterized by severe hypoxia and metabolic acidosis,
Timing of delivery
IUGR is one of the most common pregnancy complications and substantially increases the prospective risk of adverse outcome. Yet according to pregnancy audits, most instances of IUGR are not detected as such antenatally. Modern obstetric care needs to raise the level of awareness of the importance of this condition, and establish evidence-based protocols for improved surveillance.
Because the only current treatment for IUGR is delivery, the main consideration needs to be appropriate timing,
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