Stillbirth rates in high-income countries have shown little or no improvement over the past two decades. Prevention strategies that target risk factors could be important in rate reduction. This systematic review and meta-analysis was done to identify priority areas for stillbirth prevention relevant to those countries.
Population-based studies addressing risk factors for stillbirth were identified through database searches. The factors most frequently reported were identified and selected according to whether they could potentially be reduced through lifestyle or medical intervention. The numbers attributable to modifiable risk factors were calculated from data relating to the five high-income countries with the highest numbers of stillbirths and where all the data required for analysis were available. Odds ratios were calculated for selected risk factors, from which population-attributable risk (PAR) values were calculated.
Of 6963 studies initially identified, 96 population-based studies were included. Maternal overweight and obesity (body-mass index >25 kg/m(2)) was the highest ranking modifiable risk factor, with PARs of 8-18% across the five countries and contributing to around 8000 stillbirths (≥22 weeks' gestation) annually across all high-income countries. Advanced maternal age (>35 years) and maternal smoking yielded PARs of 7-11% and 4-7%, respectively, and each year contribute to more than 4200 and 2800 stillbirths, respectively, across all high-income countries. In disadvantaged populations maternal smoking could contribute to 20% of stillbirths. Primiparity contributes to around 15% of stillbirths. Of the pregnancy disorders, small size for gestational age and abruption are the highest PARs (23% and 15%, respectively), which highlights the notable role of placental pathology in stillbirth. Pre-existing diabetes and hypertension remain important contributors to stillbirth in such countries.
The raising of awareness and implementation of effective interventions for modifiable risk factors, such as overweight, obesity, maternal age, and smoking, are priorities for stillbirth prevention in high-income countries.
The Stillbirth Foundation Australia, the Department of Health and Ageing, Canberra, Australia, and the Mater Foundation, Brisbane, Australia.
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"For populations of women who do exhibit parityrelated iron depletion, health outcomes attributed to low iron in a reproductive context raise concern. Adverse obstetric outcomes noted above—low birth weight, infant anemia, and maternal and infant mortality—tend to appear more frequently in primiparous rather than multiparous women (Abrams and Newman, 1991; LanghoffRoos et al., 2006; Flenady et al., 2011; Kramer et al., 2011), although this is somewhat reversed in very parous women (Babinszki et al., 1999; Aliyu et al., 2005). One study identified both high parity (more than 5 births) and anemia as major, independent risk factors for postpartum bleeding (Kavle et al., 2008). "
"Obesity and overweight during pregnancy are well-recognized independent risk factors that contribute to the development of metabolic syndrome and several diet-related anomalies not only in the mother, but also in the fetus through fetal programming [American College of Obstetricians and Gynecologists (ACOG), 2005; Flenady et al., 2011; Triunfo and Lanzone, 2014]. This intrauterine programming can be observed as altered responses to physiological stimuli in HUVEC isolated from pathological pregnancies (Cheng et al., 2013; Krause et al., 2013). "
"Small for gestational age (SGA) status, or weight below the 10th centile, increases the risk of adverse perinatal outcomes, including stillbirth (Doctor et al. 2001; Figueras et al. 2008; Flenady et al. 2011; Froen et al. 2004; McCowan et al. 2000; Severi et al. 2002). In the United Kingdom, screening for SGA infants currently relies on maternal history and risk factors identified at the booking visit. "
[Show abstract][Hide abstract]ABSTRACT: Ultrasound estimation of placental volume (PlaV) between 11 and 13 wk has been proposed as part of a screening test for small-for-gestational-age babies. A semi-automated 3-D technique, validated against the gold standard of manual delineation, has been found at this stage of gestation to predict small-for-gestational-age at term. Recently, when used in the third trimester, an estimate obtained using a 2-D technique was found to correlate with placental weight at delivery. Given its greater simplicity, the 2-D technique might be more useful as part of an early screening test. We investigated if the two techniques produced similar results when used in the first trimester. The correlation between PlaV values calculated by the two different techniques was assessed in 139 first-trimester placentas. The agreement on PlaV and derived “standardized placental volume,” a dimensionless index correcting for gestational age, was explored with the Mann–Whitney test and Bland–Altman plots. Placentas were categorized into five different shape subtypes, and a subgroup analysis was performed. Agreement was poor for both PlaV and standardized PlaV (p < 0.001 and p < 0.001), with the 2-D technique yielding larger estimates for both indices compared with the 3-D method. The mean difference in standardized PlaV values between the two methods was 0.007 (95% confidence interval: 0.006–0.009). The best agreement was found for regular rectangle-shaped placentas (p = 0.438 and p = 0.408). The poor correlation between the 2-D and 3-D techniques may result from the heterogeneity of placental morphology at this stage of gestation. In early gestation, the simpler 2-D estimates of PlaV do not correlate strongly with those obtained with the validated 3-D technique.
Full-text · Article · Jan 2015 · Ultrasound in Medicine & Biology