Prenatal natural history of congenital pulmonary malformations: MALFPULM population-based cohort study.

<bold>Objectives: </bold>To assess prenatal changes in the volume of congenital pulmonary malformations (CPM) and examine whether these changes differ in lesions that appear cystic on ultrasound compared with hyperechoic lesions, and to study the relationship between CPM volume and risk of fetal compression.<bold>Methods: </bold>We conducted a nationally representative, multicenter, prospective cohort study, which included 579 ultrasound examinations in 176 pregnant women with a diagnosis of fetal CPM, between March 2015 and November 2016. Several ultrasound examinations were performed between diagnosis and delivery, including measurement of CPM volume. We modeled changes in CPM volume ratio (CVR) as a function of gestational age, overall and for cystic/mixed vs hyperechoic malformations, and examined the association between CVR and signs of compression during pregnancy.<bold>Results: </bold>When modeling CVR changes over time, there was a statistically significant decrease in CVR with increasing gestational age (P < 0.001), but the pattern of change differed according to CPM phenotype at first ultrasound examination: cystic/mixed CPM were characterized by a monotonic decrease in CVR with increasing gestational age (P = 0.002), whereas hyperechoic CPM showed an initial increase in CVR up to 27 weeks of gestation, followed by a decrease thereafter (P < 0.001). Peak CVR values were predicted as early as 21-22 weeks for cystic/mixed CPMs compared with 25-26 weeks for hyperechoic malformations. Regardless of CPM phenotype, fetuses that showed no sign of compression at any point had substantially lower CVR at first CVR measurement, and the CVR remained relatively constant thereafter. Among the subpopulation of fetuses with no sign of compression at first CVR measurement, the odds of a subsequent compression was 7-fold higher (adjusted odds ratio, 7.0; 95% CI, 1.6-29.9) if initial CVR was > 0.4 vs CVR ≤ 0.4 cm2 .<bold>Conclusions: </bold>Predicted changes in CVR during pregnancy differ between cystic and hyperechoic malformations. This may be the result of different pathophysiological mechanisms or differences in the timing of occurrence of these different types of CPM. CVR measured at the initial diagnostic ultrasound examination was strongly associated with the odds of subsequent compression. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]