Perinatal & Pediatric
Fetal body composition and organ growth patterns in pregnancies complicated by first-trimester vaginal bleeding: NICHD Fetal 3D Study Alexandra Jean-Louis* Alexandra Jean-Louis Jessica L. Gleason Kathryn A. Wagner Zhen Chen Daniel He Roger B. Newman William A. Grobman Robert E Gore-Langton Seth Sherman Magdalena Sanz Cortes Edward K. Chien Luis F. Goncalves Katherine L. Grantz
Background: In the NICHD Fetal Growth Study, women who self-reported more than one day of vaginal bleeding in the first trimester had lower estimated fetal weight (EFW) by 2-dimensional ultrasound at 35 to 39 weeks, and lower birthweight compared to women without bleeding. We followed up these findings to explore associations between bleeding and fetal body composition and organ volumes by 3-dimensional (3D) ultrasound.
Methods: The NICHD Fetal 3D Study (2009-2013) included singleton pregnancies at low risk for fetal growth abnormalities (n=2634). Fetal fat and lean measures of arm, abdomen, and thigh, and organ volumes, including cerebellum, lung, kidney, and liver volumes were measured up to five times between 15-40 weeks using 3D ultrasound. Women were grouped by cumulative days of first trimester bleeding: 0 (reference), 1, or >1 day. Linear mixed models, with quadratic and cubic terms for gestational age, including global tests for overall differences in trajectories and weekly pairwise comparisons, were fit to compare bleeding groups for each 3D volume, adjusted for maternal age, race/ethnicity, and pre-pregnancy BMI.
Results: Most women had 0 days of bleeding (n=2144, 81.4%), while 211 (8.0%) bled for 1 day and 279 (10.6%) bled for >1 day. Compared to those with no bleeding (Figure), fetuses of women with >1 day of bleeding had smaller abdominal area (-78.4 mm2 to -293.8 mm2) between 29-40 weeks, and smaller fractional thigh volume (-2.2 cm3 to -4.1 cm3) between 36-40 weeks. Fetuses of women with 1 day of bleeding also had smaller liver volume compared to no bleeding (-3.8 cm3 to -6.1 cm3) between 29-33 weeks, though results were attenuated when adjusting for estimated fetal weight.
Conclusion: First-trimester bleeding was associated with smaller fetal abdominal area, thigh, and liver growth. Fetal 3D measures may provide additional insight into how early pregnancy bleeding may potentially impact fetal growth and subsequent postnatal health outcomes.
