Restricted fetal growth in sudden intrauterine unexplained death.
BACKGROUND
Unexplained antepartum stillbirth is a common cause of perinatal death, and identifying the fetus at risk is a challenge for obstetric practice. Intrauterine growth restriction (IUGR) is associated with a variety of adverse perinatal outcomes, but reports on its impact on unexplained stillbirths by population-based birthweight standards have been varying, including both unexplained and unexplored stillbirths.


OBJECTIVE
We have studied IUGR, assessed by individually adjusted fetal weight standards, in antepartum deaths that remained unexplained despite thorough postmortem investigations.


METHODS
Antenatal health cards from a complete population-based 10-year material of 76 validated sudden intrauterine unexplained deaths were compared to those of 582 randomly selected liveborn controls. Birthweight <10th percentile of the individualized standard adjusted for gestational age, maternal height, weight, parity, ethnicity, and fetal gender was defined as growth restriction.


RESULTS
52% of unexplained stillbirths were growth restricted, with a mean gestational age at death of 35.1 weeks. Suboptimal growth was the most important fetal determinant for sudden intrauterine unexplained death (odds ratio 7.0, 95% confidence interval 3.3-15.1). Concurrent maternal overweight or obesity, high age, and low education further increase the risk. Overweight and obesity increase the risk irrespective of fetal growth, and while high maternal age increases the risk of the normal weight fetus, it is not associated to growth restriction as a precursor of sudden intrauterine unexplained death.


CONCLUSIONS
IUGR is an important risk factor of sudden intrauterine unexplained death, and this should be excluded in pregnancies with any other risk factor for sudden intrauterine unexplained death.
Frøen
J Frederik
JF
Department of Obstetrics and Gynecology, Rikshospitalet University Clinic, University of Oslo, Oslo, Norway. j.f.froen@klinmed.uio.no
Gardosi
Jason O
JO
Thurmann
Anne
A
Francis
André
A
Stray-Pedersen
Babill
B
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D015992:Body Mass Index; D016022:Case-Control Studies; D016001:Confidence Intervals; D003645:Death, Sudden / Q000453:epidemiology*; D005260:Female; D005313:Fetal Death / Q000453:epidemiology*; D005317:Fetal Growth Retardation / Q000175:diagnosis* / Q000453:epidemiology*; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008423:Maternal Age; D015999:Multivariate Analysis; D009765:Obesity / Q000453:epidemiology; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D011295:Prenatal Care; D012189:Retrospective Studies; D018570:Risk Assessment; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology