Yale Image Finder

Search the actual image content of 1,538,051 (and growing!) Open Access images and figures from PubMed Central.


Advanced...

Related Figures


Figure 3 Gestational age-specific stillbirth, neo...

Figure 3 Stillbirth, early neonatal death and per...

Figure 1 Risk by week of gestation for stillbirth...

Figure 1 Flow of study participants.*A miscarriag...

Figure 1 Gestational age-specific rates of SIDS b...

Figure 1 Phenotypic relationship between gestatio...

Figure 2 Changes in the gestational age distribut...

Figure 3 Changes in the gestational age distribut...

Flow diagram of study recruitment and fo...

Figure 2 Incidence of birth (panel A) and perinat...

Figure 2: Schematic depiction of pregnancy course and options for calculating the gestational age-specific stillbirth rate. Traditional calculation: Number of stillbirth at any gestational week/Number of total births at that gestational week = 1/4 = 250 per 1,000 total births. Fetuses at risk calculation: Number of stillbirths at any gestational week/Number of fetuses at risk of stillbirth at that gestational week = 1/16 = 63 per 1,000 fetuses at risk.

Image Text (High Precision): 1/16 1/4 Fetuses Gestational Risk Stillbirth Traditional age births model period rate total weeks

Other Images from "Theory of obstetrics: An epidemiologic framework for justifying medically indicated early delivery":


Figure 4 Schematic depiction of the survival anal...

Figure 2 Schematic depiction of pregnancy course ...

Figure 5 Incidence of labor induction/cesarean de...

Figure 1 Gestational age distribution (1a) and ge...

Figure 3 Schematic depiction of pregnancy course ...

[Full Text] [PDF]

Abstract

BackgroundModern obstetrics is faced with a serious paradox. Obstetric practice is becoming increasingly interventionist based on empirical evidence but without a theoretical basis for such intervention. Whereas obstetric models of perinatal death show that mortality declines exponentially with increasing gestational duration, temporal increases in medically indicated labour induction and cesarean delivery have resulted in rising rates of preterm birth and declining rates of postterm birth. Other problems include a disconnection between patterns of gestational age-specific growth restriction (constant across gestation) and gestational age-specific perinatal mortality (exponential decline with increasing duration) and the paradox of intersecting perinatal mortality curves (low birth weight infants of smokers have lower neonatal mortality rates than the low birth weight infants of non-smokers).DiscussionThe fetuses at risk approach is a causal model that brings coherence to the various perinatal phenomena. Under this formulation, pregnancy complications (such as preeclampsia), labour induction/cesarean delivery, birth, revealed small-for-gestational age and death show coherent patterns of incidence. The fetuses at risk formulation also provides a theoretical justification for medically indicated early delivery, the cornerstone of modern obstetrics. It permits a conceptualization of the number needed to treat (e.g., as low as 2 for emergency cesarean delivery in preventing perinatal death given placental abruption and fetal bradycardia) and a calculation of the marginal number needed to treat (i.e., the number of additional medically indicated labour inductions/cesarean deliveries required to prevent one perinatal death). Data from the United States showed that between 1995–96 and 1999–2000 rates of labour induction/cesarean delivery increased by 45.1 per 1,000 and perinatal mortality decreased by 0.31 per 1,000 total births among singleton pregnancies at > = 28 weeks of gestation. The marginal number needed to treat was 145 (45.1/0.31), showing that 145 excess labour inductions/cesarean deliveries in 1999–2000 (relative to 1995–96) were responsible for preventing 1 perinatal death among singleton pregnancies at > = 28 weeks gestation.SummaryThe fetuses at risk approach, with its focus on incidence measures, provides a coherent view of perinatal phenomena. It also provides a theoretical justification for medically indicated early delivery and reconciles the contemporary divide between obstetric theory and obstetric practice.


Search: Image Text (High Recall) Image Text (High Precision) Caption Abstract Title Full Text

All images and content copyright their respective owners. All else copyright ©2007-2008, Krauthammer Lab, Yale University.

Sign up for Yale Image Finder announcements:

Email: