Limits...
An adjustable fetal weight standard for twins: a statistical modeling study.

Zhang J, Mikolajczyk R, Lei X, Sun L, Yu H, Cheng W - BMC Med (2015)

Bottom Line: The adjustable fetal weight standard has an excellent match with the observed birthweight data in non-Hispanic White, non-Hispanic Black, Hispanics, and Asian from 24 to 38 weeks gestation.It also had a very good fit with cross-sectional data from Australia and Norway, and a longitudinal standard from Brazil.The adjustable fetal weight standard for twins is a flexible tool and can be used in different populations.

View Article: PubMed Central - PubMed

Affiliation: MOE-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, 1665 Kong Jiang Road, Shanghai, 200092, China. junjimzhang@gmail.com.

ABSTRACT

Background: It is a common practice to use a singleton fetal growth standard to assess twin growth. We aim to create a twin fetal weight standard which is also adjustable for race/ethnicity and other factors.

Methods: Over half a million twin births of low risk pregnancies in the US, from 1995 to 2004, were used to construct a fetal weight standard. We used the Hadlock's fetal growth standard and the proportionality principle to make the standard adjustable for other factors such as race/ethnicity. We validated the standard in different race/ethnicities in the US and against previously published curves from around the world.

Results: The adjustable fetal weight standard has an excellent match with the observed birthweight data in non-Hispanic White, non-Hispanic Black, Hispanics, and Asian from 24 to 38 weeks gestation. It also had a very good fit with cross-sectional data from Australia and Norway, and a longitudinal standard from Brazil. However, our model-based 10th and 90th percentiles differed substantially from studies in Japan and US that used the last menstrual period for estimate of gestational age.

Conclusion: The adjustable fetal weight standard for twins is a flexible tool and can be used in different populations.

Show MeSH

Related in: MedlinePlus

Comparisons between observed birthweight (Norway [15], Australia [16], Japan [17]), estimated fetal weight (US [3], Brazil dichorionic and monochorionic [19]), and adjusted fetal weight by the adjustable fetal weight standard for twins in five previous studies. The 50th percentile birthweight was selected in the Norwegian and Australian studies [15, 16]
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Fig4: Comparisons between observed birthweight (Norway [15], Australia [16], Japan [17]), estimated fetal weight (US [3], Brazil dichorionic and monochorionic [19]), and adjusted fetal weight by the adjustable fetal weight standard for twins in five previous studies. The 50th percentile birthweight was selected in the Norwegian and Australian studies [15, 16]

Mentions: We also compared twin birthweight references from Australia, Norway, and Japan. Figure 4 (left column) shows that the observed and adjusted curves overlapped for both males and females in Australia and Norway. However, the curves differed quite substantially for Japan. Although the 10th percentile curves were similar, the 50th and 90th percentiles curves were much higher than those of the adjustable standard, particularly in early gestation. Furthermore, in the Japanese data the percentile ranges were much wider in early gestation, lacking a typical gramophone shape. This phenomenon was also observed in a US cross-sectional study using clinically recorded estimated fetal weight (Fig. 4, right column). In contrast, the adjustable standard matched well with a Brazilian cross-sectional study with estimated fetal weight in both monochorionic and dichorionic twins. It is interesting to note that the 5th and 95th limits were appreciably wider for the monochorionic than the dichorionic twins.Fig. 4


An adjustable fetal weight standard for twins: a statistical modeling study.

Zhang J, Mikolajczyk R, Lei X, Sun L, Yu H, Cheng W - BMC Med (2015)

Comparisons between observed birthweight (Norway [15], Australia [16], Japan [17]), estimated fetal weight (US [3], Brazil dichorionic and monochorionic [19]), and adjusted fetal weight by the adjustable fetal weight standard for twins in five previous studies. The 50th percentile birthweight was selected in the Norwegian and Australian studies [15, 16]
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4491250&req=5

Fig4: Comparisons between observed birthweight (Norway [15], Australia [16], Japan [17]), estimated fetal weight (US [3], Brazil dichorionic and monochorionic [19]), and adjusted fetal weight by the adjustable fetal weight standard for twins in five previous studies. The 50th percentile birthweight was selected in the Norwegian and Australian studies [15, 16]
Mentions: We also compared twin birthweight references from Australia, Norway, and Japan. Figure 4 (left column) shows that the observed and adjusted curves overlapped for both males and females in Australia and Norway. However, the curves differed quite substantially for Japan. Although the 10th percentile curves were similar, the 50th and 90th percentiles curves were much higher than those of the adjustable standard, particularly in early gestation. Furthermore, in the Japanese data the percentile ranges were much wider in early gestation, lacking a typical gramophone shape. This phenomenon was also observed in a US cross-sectional study using clinically recorded estimated fetal weight (Fig. 4, right column). In contrast, the adjustable standard matched well with a Brazilian cross-sectional study with estimated fetal weight in both monochorionic and dichorionic twins. It is interesting to note that the 5th and 95th limits were appreciably wider for the monochorionic than the dichorionic twins.Fig. 4

Bottom Line: The adjustable fetal weight standard has an excellent match with the observed birthweight data in non-Hispanic White, non-Hispanic Black, Hispanics, and Asian from 24 to 38 weeks gestation.It also had a very good fit with cross-sectional data from Australia and Norway, and a longitudinal standard from Brazil.The adjustable fetal weight standard for twins is a flexible tool and can be used in different populations.

View Article: PubMed Central - PubMed

Affiliation: MOE-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, 1665 Kong Jiang Road, Shanghai, 200092, China. junjimzhang@gmail.com.

ABSTRACT

Background: It is a common practice to use a singleton fetal growth standard to assess twin growth. We aim to create a twin fetal weight standard which is also adjustable for race/ethnicity and other factors.

Methods: Over half a million twin births of low risk pregnancies in the US, from 1995 to 2004, were used to construct a fetal weight standard. We used the Hadlock's fetal growth standard and the proportionality principle to make the standard adjustable for other factors such as race/ethnicity. We validated the standard in different race/ethnicities in the US and against previously published curves from around the world.

Results: The adjustable fetal weight standard has an excellent match with the observed birthweight data in non-Hispanic White, non-Hispanic Black, Hispanics, and Asian from 24 to 38 weeks gestation. It also had a very good fit with cross-sectional data from Australia and Norway, and a longitudinal standard from Brazil. However, our model-based 10th and 90th percentiles differed substantially from studies in Japan and US that used the last menstrual period for estimate of gestational age.

Conclusion: The adjustable fetal weight standard for twins is a flexible tool and can be used in different populations.

Show MeSH
Related in: MedlinePlus