GEOPHYSICAL RESEARCH LETTERS, VOL. ???, XXXX, DOI:10.1029/,
A fake paper prepared for April Fool’s day (my birthday)
Data show no recent hiatus in the estimated fetal weight of
Kohyama’s baby
Tsubasa Kohyama1 and Rikako Kohyama1
Abstract.
The estimated fetal weight of Kohyama’s baby is calculated using empirical formulae based on biparietal diameter,
antero-posterior trunk diameter, transverse trunk diameter,
femur length, and abdominal circumference. The new data
from Inage Birth Clinic in Chiba, Japan, refute the notion
that there has been a slowdown or “hiatus” in the rate of
the estimated weight of Kohyama’s baby in recent weeks.
Acknowledgments. We acknowledge Inage Birth Clinic.
1. Introduction
The apparent observed slowing or decrease in the upward
rate of the estimated weight of Kohyama’s baby has been
nicknamed the “hiatus.” The Inage-dwelling Parents of the
Cheerful Child (IPCC) Fifth Assessment Report (AR5), released in stages between March and April 2016, has concluded that the estimated fetal weight (EFW) trend from
the 20th week through the 25th week was lower than the
trend from the 30th week through the 35th week.
Figure 1. Schematic showing the variables used to
estimate the fetal weight. Courtesy of the Group of
Preparation for Health Guidance Manual on EFW. The
manual is downloaded from http://www.jsog.or.jp/
public/shusanki/taiji_taiju_hatsuiku_201203.pdf
2. Data and Method
The observed data of biparietal diameter (BPD), anteroposterior trunk diameter (APTD), transverse trunk diameter (TTD), femur length (FL), abdominal circumference
(AC) used in this study are collected by Inage Birth Clinic,
Chiba, Japan (Fig. 1).
The empirical formulae widely used to estimate the EFW
in Japan are the followings:
EF W = 1.07BP D 3 + 0.30AC 2 · F L
(1)
EF W = 1.07BP D 3 + 3.42AP T D · T T D · F L
(2)
where each variable follows the centimeter-gram-second
(CGS) system of units [Shinozuka, 1987; Shinozuka 2000].
The author is not sure which formula they used :)
3. Result
The result is shown in Fig. 2.
Figure 2. Time series of the estimated weight of
Kohyama’s baby and the statistics of Japanese babies. The white markers show the weight of Kohyama’s
baby estimated using the empirical formula. The white
solid line shows the mean, and the black dashed lines
show the 1.5 standard deviation range estimated from
samples of Japanese babies. Courtesy of Inage Birth
Clinic.
4. Conclusion
We should not calculate trends without statistical tests.
Because the trend calculations are done using only two samples, the correlation coefficients are unity. The estimated
range of the true trends are plus-minus infinity, however.
References
Shinozuka N, Okai T, Kozuma S, Mukubo M, Shih CT,
Maeda T, Kuwabara Y, Mizuno M. (1987), Formulas for Fetal Weight Estimation by Ultrasound Measurements Based
on Neonatal Specific Gravities and Volumes, Am. J. Obstet.
Gynecol., 157 (51), 1140-1145.
Shinozuka N, Akamatsu N, Sato S, Kanzaki T, Takeuch
H, Natori M, Chiba Y, Okai T. (2000), Ellipse Tracing Fetal Growth Assessment Using Abdominal Circumference :
JSUM Standardization Committee for Fetal Measurements,
J. Med. Ultrasound., 8 (21), 87-94.
1 Kohyama
family, Inage, Chiba, Japan.
Copyright 2016 by the American Geophysical Union.
0094-8276/16/$5.00
1