Longitudinal reference charts for growth of the fetal head, abdomen and femur

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Abstract

Objectives

The aims of the present study were to establish improved reference charts for growth of the fetal head, abdomen and femur, and to determine the effect of fetal and maternal factors.

Study design

This prospective longitudinal study included 650 low-risk pregnancies. Outer–outer biparietal diameter (BPD), head circumference (HC), mean abdominal diameter (MAD), abdominal circumference (AC) and femur length (FL) were measured by ultrasound, and the statistical analysis was based on regression analysis and multilevel modeling.

Results

Reference percentiles for the growth of MAD, AC and FL showed continuous growth in gestational week 10–40, while BPD and HC showed a slightly blunted growth toward the end of pregnancy. FL was the only variable that was not influenced by gender. There was a significant negative association between breech presentation and all five biometrical variables, while maternal weight was positively associated with all five variables. Cephalic index significantly influenced BPD and HC. Maternal height had a positive effect on BPD, HC, AC and FL, and parity had a positive effect on MAD and AC, while smoking influenced negatively HC, MAD, and FL. Terms for calculating conditional reference values and customisation for individualised growth assessment are presented.

Conclusions

New reference charts for the growth of fetal head, abdomen and femur are suggested for assessing fetal size and growth, and can be adjusted for maternal and fetal factors to suite individual pregnancies.

Introduction

Serial measurements in order to assess fetal growth were introduced by Willocks [1], and the first longitudinal chart for biparietal diameter was presented by Campbell and Newman [2]. However, many obstetricians use cross-sectional charts for their serial examinations of the fetus, even though cross-sectional studies are not designed to evaluate growth. Royston points out that when using size-charts instead of growth charts to determine growth, the obstetrician may be misled [3]. In contrast to cross-sectional data, longitudinal data have a hierarchical structure based on two levels of variation: within fetuses between gestational ages (level 1), and variation between fetuses (level 2) [4], [5], [6].

Many of the existing longitudinal studies of fetal growth during the second and third trimester included a limited number of pregnancies [7], [8], [9], [10], [11], [12], [13], analysed the data as in a cross-sectional fashion [7], [11], [12], [13], [14], [15], or the statistical methods were not presented [16]. In recent years more appropriately designed studies have been published. In 1998, Owen and Ogston presented conditional biometric growth charts based on a larger study population (274 pregnancies) analysed by multilevel models [17], and in 2000 longitudinal unconditional growth charts were published from Italy [18]. In 2003, a third study from Hong Kong was published [19]. This was a customised study where maternal weight at booking, height, parity and fetal sex were included in the construction of the biometric charts.

For most of the fetal biometrical variables, unconditional, uncustomised growth charts based on our population are lacking.

Our population has changed during the last 30–40 years, height and weight have increased for both men and women [20]. Birth weight by gestational age for all term weeks has increased for the same period [21] and so has the number of macrosomic neonates [22].

Thus, the aim of the present study was to establish reference charts for ultrasound measurements of the fetal head, abdomen and femur, designed in line with updated statistical methods. We also wanted to determine the effect of fetal and maternal factors on these growth patterns and develop conditional and customised growth models.

Section snippets

Materials and methods

A group of 650 healthy women was recruited from a low-risk antenatal clinic to a larger prospective ultrasound study of fetal biometrical measurements. The first part of the study was cross-sectional and aimed at establishing charts for the assessment of gestational age at 10–24 weeks [23]. The present study was designed longitudinally to establish growth charts for biometrical measurements. The participants were healthy women with regular menstrual periods (28 ± 4 days), singleton pregnancies

Results

There was one early miscarriage at 19 weeks, one fetus died at 28 weeks (hypoplastic left heart syndrome), and three fetuses died in utero during third trimester, one due to abruptio placentae and two for no obvious reason. In another case of hypoplastic left heart syndrome the woman applied for termination of pregnancy. During pregnancy 2.6% of the women developed preeclampsia or hypertension. Four women withdrew after the first examination. None of the above mentioned cases were excluded. A

Comments

We have constructed new reference charts for growth of the five biometrical variables, BPD, HC, MAD, AC and FL for gestational age 10–40 weeks (Table 2, Table 3, Table 4, Table 5, Table 6), and found that maternal and fetal factors had a small but significant impact on the growth of these parameters (Table 7). We have provided the terms needed for customising these charts to individual characteristics (Appendix A, Appendix B).

Charts of fetal biometry can be used for three different purposes: to

Acknowledgments

Professor Stein Tore Nilsen gave important support in the initial stages of this study. Bernard J. Evans, M.D., B.Sc., Ph.D. revised the manuscript. The Research Council of Norway and Haukeland University Hospital supported the study financially.

References (31)

  • J. Willocks

    The use of ultrasonic cephalometry

    Proc R Soc Med

    (1962)
  • S. Campbell et al.

    Growth of the fetal biparietal diameter during normal pregnancy

    J Obstet Gynaecol Br Commonw

    (1971)
  • P. Royston et al.

    How to construct ’normal ranges’ for fetal variables

    Ultrasound Obstet Gynecol

    (1998)
  • D.G. Altman et al.

    Design and analysis of studies to derive charts of fetal size

    Ultrasound Obstet Gynecol

    (1993)
  • P. Royston et al.

    Design and analysis of longitudinal studies of fetal size

    Ultrasound Obstet Gynecol

    (1995)
  • H. Goldstein

    Efficient statistical modelling of longitudinal data

    Ann Hum Biol

    (1986)
  • P.H. Persson et al.

    Normal range growth curves for fetal biparietal diameter, occipito frontal diameter, mean abdominal diameters and femur length

    Acta Obstet Gynecol Scand

    (1986)
  • P.S. Eriksen et al.

    Normal growth of the fetal biparietal diameter and the abdominal diameter in a longitudinal study. An evaluation of the two parameters in predicting fetal weight

    Acta Obstet Gynecol Scand

    (1985)
  • R.L. Deter et al.

    Growth standards for anatomic measurements and growth rates derived from longitudinal studies of normal fetal growth

    J Clin Ultrasound

    (1992)
  • P. Bergsjo et al.

    Growth of the fetal skull, with special reference to weight-for-dates of the newborn child

    Acta Obstet Gynecol Scand

    (1976)
  • P. Jeanty et al.

    A longitudinal study of fetal head biometry

    Am J Perinatol

    (1984)
  • P. Jeanty et al.

    A longitudinal study of fetal limb growth

    Am J Perinatol

    (1984)
  • P. Jeanty et al.

    Normal growth of the abdominal perimeter

    Am J Perinatol

    (1984)
  • S. Gallivan et al.

    An investigation of fetal growth using serial ultrasound data

    Ultrasound Obstet Gynecol

    (1993)
  • P. Schwarzler et al.

    Sex-specific antenatal reference growth charts for uncomplicated singleton pregnancies at 15–40 weeks of gestation

    Ultrasound Obstet Gynecol

    (2004)
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