Modelling the conception to first birthday mortality curve

Dr Paul Williamson & Prof. Bob Woods

Department of Geography

Workshop on Fetal and Infant Survival

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Days after LMP

Dyi

ng o

ut o

f 10

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once

ptio

ns

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Dyi

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ut o

f 10

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Days after LMP

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Embryo: 14-41 days after LMPEarly fetal: 42-195 days after LMPLate fetal (stillbirths): 196-279 days after LMPEarly neonatal: 280-286 days after LMPLate neonatal: 287-307 days after LMPPost neonatal: 308-644 days after LMP

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Days after LMP

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ncep

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Component 1 Component 2 Component 3 Model

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Days after LMP

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Model Observed

H

G

xE

D

xx

Bxo

e

F

e

CAeyy

)()( )()(

11

ˆ0

Where

y^ = predicted fetal-infant loss per 1000 conceptionsx = days after LMPyo = 473.3523 xo = 280A = -2549.0207 B = 0.1197 C = 28.9374 D = 6.8747E = 1.1418 F = 84.4912 G = 154.719 H = 11.1787

a) Component 1 embryonic and early fetal loss [14-196 days after LMP]

Bxo Aeyy 1ˆ

[Exponential growth curve]

b) Component 2 late fetal and neonatal [196-308 days after LMP]

E

D

xx o

e

Cy

)( )(2

1

ˆ

[Aysmmetrical sigmoidal (4 params.)]

c) Component 3 post-neonatal [308-644 days after LMP]

H

G

x

e

Fy

)( )(3

1

ˆ

[Asymmetrical sigmoidal (3 params.)]