Sonographic fetal weight estimation in normal and overweight/obese healthy term pregnant women by gestation-adjusted projection (GAP) method.
OBJECTIVE
The objective of this study is to assess the ultrasound accuracy in fetal weight estimation related to the time distance between the actual weight recorded at delivery and the period of sonography among normal and overweight/obese pregnant women within 3 weeks prior birth at term.


METHODS
Four-hundred and ninety patients with healthy pregnancy were studied in a cohort study. The absolute percent error in estimation was achieved by gestation-adjusted projection method from Hadlock model for weight calculation as measure of accuracy. The mean percentage error variation over the weeks was correlated to maternal body mass index (BMI, Kg/m(2)) at ultrasound. The relationship between BMI and ultrasound performance was assessed by linear regression.


RESULTS
The overall proportion of supposed sonographic estimated fetal weight at birth within ±10 % of the birth weight significantly declines over the weeks (P = .016). The trend toward a progressive deterioration in ultrasound accuracy is not statistically significant for normal weight women (P = .272) but it is for over-weight/obese (P = .044). On univariate analysis, the absolute percent error and absolute error are positively related to BMI.


CONCLUSIONS
Accuracy is related to the week at ultrasound scan with a gradual deterioration over the time and it worsens with increasing distance in days between the date of ultrasounds and delivery. The deterioration is greater for BMI ≥ 25.
Obstetrics and Gynecology Unit, Azienda Ospedaliera Arcispedale Santa Maria Nuova, Viale Risorgimento 80, 42123, Reggio Emilia, Italy. Simone.Paganelli@asmn.re.it.
Simone
S
Paganelli
Obstetrics and Gynecology Unit, Azienda Ospedaliera Arcispedale Santa Maria Nuova, Viale Risorgimento 80, 42123, Reggio Emilia, Italy.
Emanuele
E
Soncini
Obstetrics and Gynecology Unit, Azienda Ospedaliera Arcispedale Santa Maria Nuova, Viale Risorgimento 80, 42123, Reggio Emilia, Italy.
Giuseppina
G
Comitini
Obstetrics and Gynecology Unit, Azienda Ospedaliera Arcispedale Santa Maria Nuova, Viale Risorgimento 80, 42123, Reggio Emilia, Italy.
Stefano
S
Palomba
Obstetrics and Gynecology Unit, Azienda Ospedaliera Arcispedale Santa Maria Nuova, Viale Risorgimento 80, 42123, Reggio Emilia, Italy.|University of Modena and Reggio Emilia, Via del Pozzo, 71, 41124, Modena, Italy.
Giovanni Battista
GB
La Sala
D000328:Adult; D000886:Anthropometry; D001699:Biometry; D001724:Birth Weight; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D020567:Fetal Weight; D006801:Humans; D007230:Infant, Low Birth Weight / Q000502:physiology*; D007231:Infant, Newborn; D009765:Obesity; D050177:Overweight; D011237:Predictive Value of Tests; D011247:Pregnancy; D037841:Pregnant People; D012044:Regression Analysis; D047929:Term Birth; D016216:Ultrasonography, Prenatal / Q000379:methods / Q000592:standards*
Estimated fetal weight accuracy; Fetal weight formulas; Hadlockfetal weight; Obesity; Sonographicfetal weight estimation; Ultrasound estimated fetal weight; Ultrasound fetal weight