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.

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Related in: MedlinePlus

Comparisons between observed and adjusted fetal growth curve in two longitudinal studies [19, 20]
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Fig5: Comparisons between observed and adjusted fetal growth curve in two longitudinal studies [19, 20]

Mentions: Finally, we compared our standard with two longitudinal fetal growth standards from Brazil and the US (Fig. 5) [19, 20]. The Brazilian study serially measured 125 low-risk twin sets every 3 weeks, on average, from 14 to 38 weeks gestation. Multilevel regression analysis was performed on normalized data. Our adjustable curves matched well with the longitudinal standard, except that the Brazilian standard had a higher 90th percentile curve than the adjustable standard. Yarkoni et al. [20] conducted a small longitudinal study in 35 healthy women with normal twin pregnancies in the US. Ultrasound measures were taken every 3 weeks from 15 weeks gestation to delivery. Noticeably, the 5th and 95th limits were less stable probably due to the small sample size. However, the 50th percentile curve was almost identical to ours.Fig. 5


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 and adjusted fetal growth curve in two longitudinal studies [19, 20]
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig5: Comparisons between observed and adjusted fetal growth curve in two longitudinal studies [19, 20]
Mentions: Finally, we compared our standard with two longitudinal fetal growth standards from Brazil and the US (Fig. 5) [19, 20]. The Brazilian study serially measured 125 low-risk twin sets every 3 weeks, on average, from 14 to 38 weeks gestation. Multilevel regression analysis was performed on normalized data. Our adjustable curves matched well with the longitudinal standard, except that the Brazilian standard had a higher 90th percentile curve than the adjustable standard. Yarkoni et al. [20] conducted a small longitudinal study in 35 healthy women with normal twin pregnancies in the US. Ultrasound measures were taken every 3 weeks from 15 weeks gestation to delivery. Noticeably, the 5th and 95th limits were less stable probably due to the small sample size. However, the 50th percentile curve was almost identical to ours.Fig. 5

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