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


METHODS
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.
Johnsen
Synnøve Lian
SL
Department of Obstetrics and Gynaecology, Haukeland University Hospital, Bergen N-5021, Norway. synnove.johnsen@helse-bergen.no
Wilsgaard
Tom
T
Rasmussen
Svein
S
Sollien
Rita
R
Kiserud
Torvid
T
D000005:Abdomen / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000196:embryology; D000328:Adult; D005260:Female; D005269:Femur / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000196:embryology / Q000254:growth & development; D047109:Fetal Development; D005333:Fetus / Q000033:anatomy & histology* / Q000196:embryology; D005865:Gestational Age; D006257:Head / Q000033:anatomy & histology* / Q000196:embryology / Q000254:growth & development; D006801:Humans; D008137:Longitudinal Studies; D011247:Pregnancy; D011446:Prospective Studies; D012016:Reference Values; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000379:methods*