Prognosis of fetal macrosomy by fetal weight in the third trimester

Abstract

Introduction. Fetal macrosomy is associated with the risk of maternal and fetal trauma, shoulder dystocia, increase frequency of cesarean section, and obstetric hemorrhage. Prediction of large fetal size at the antenatal stage remains an urgent issue, definitively unresolved even with the use of modern medical imaging techniques. Materials and Methods. A total of 819 women were examined, of whom 365 (the study group) gave birth to a baby weighing more than 4000 grams, and 454 (the control group) gave birth to a full-term baby within the gestational weight norm. At 32–34 weeks of gestational screening in the third trimester, all women underwent an ultrasound examination followed by calculation of estimated fetal weight using the Hadlock formula. The inclusion criteria were fetal anthropometric data at 32–34 weeks' gestational age within the normal range, i.e. within the 10-90th percentile corridor. Results. There was a difference between the groups, the fetal weight in women in the main group in the third trimester, calculated by the Hadlock formula, was significantly higher and was 2123 grams (Q1; Q3 – 1948; 2278) compared to the control group, in which the weight was 1990 grams (Q1; Q3 – 1844; 2101), p < 0.001. ROC-analysis revealed a low, but statistically significant diagnostic value of this parameter for the prognosis of fetal macrosomia. Discussion. The practical importance of determining the risk of fetal macrosomia cannot be overestimated. Using prognostic methods, it is possible to take measures to prevent maternal and fetal trauma and to prevent perinatal morbidity. Our results show that even the isolated use of the estimated fetal weight estimation by the Hadlock method, performed in a Level III institution, allows us to identify a group of pregnant women at risk for fetal macrosomia with acceptable sensitivity and specificity. The threshold fetal weight at 32–34 weeks is 2032 grams. Obviously, ultrasound at 32–34 weeks remains essential as a selective screening technique, e.g. in the presence of known risk factors for fetal macrosomia. Conclusion. Antenatal 2D ultrasound sonography to determine the risk of fetal oversize fetuses performed as part of third-trimester prenatal screening is a tool for selective screening. The development of integral multifactorial prognostic models of fetal macrosomia based on the calculation of estimated fetal weight using the Hadlock method at 32-34 weeks seems to be a promising direction that will significantly improve the quality of perinatal care.