Influence of Maternal Asthma and Asthma Severity on Newborn Morphometry

Abstract

Objective. To determine if maternal asthma or asthma severity affects newborn morphometry. Study Design. A secondary analysis was performed on data collected in a multicenter prospective observational cohort study of asthma in pregnancy. Patients enrolled included women with asthma stratified by severity of disease and controls. Asthma severity was defined according to the classification proposed by the National Asthma Education Program (NAEP) Report of the Working Group on Asthma and Pregnancy, modified to include medication requirements. Newborn morphometry measurements included birth weight (BW) and multiples of the median birth weight (BW-MOM), head circumference (HC), length (L), HC:BW ratio, and ponderal index (PI). Results. Of 2480 patients there were 828 nonasthmatic controls, 828 with mild, 775 with moderate, and 49 with severe disease. Comparing all groups, there were statistically significant differences in maternal age (p < .001), race (p = .005), parity (p = .006), prepregnancy weight (p = .028), and medical care source (p = .001), with the severe asthma group having the highest mean maternal age (25.7 years), and proportion of African Americans (71.4%), proportion of multiparous patients (63.3%), and proportion of patients receiving government assistance (85.7%). When the control group was excluded from the comparisons, differences in prepregnancy weight and medical care source were no longer significant. BW-MOM and L did not differ between groups. The HC:BW ratio increased with asthma severity (p = .029) and was increased compared to controls (p = .010). This remained significant after controlling for confounding variables (both p <.001). HC was statistically significantly different between all groups (p = .032), as well as among women with varying degrees of asthma severity (p = .013), which was not clinically significant. After covariates adjustment, HC was not significantly different among all groups (p = .228), nor the asthma groups (p = .144). Conclusion. Asthma severity is associated with an increased HC:BW ratio. Severity was not found to impact HC, BW-MOM, L, or PI independently. However, the magnitudes of the effects were too small to suggest a clinically significant effect of asthma on neonatal morphometry in this large prospectively studied sample.

Keywords :

• asthma
• neonatal morphometry
• pregnancy

Acknowledgments

Supported by grants from the National Institute of Child Health and Human Development (HD21410, HD21414, HD21434, HD27869, HD27917, HD27905, HD27889, HD27860, HD27861, HD27915, HD27883, HD34122, HD34116, HD34210, HD34208, HD34136, HD19897, and HD36801) and the National Heart, Lung, and Blood Institute.

The authors thank Mitchell P. Dombrowski, M.D., for his assistance in the design of the study and his role as the Primary Protocol Subcommittee Committee Chair.

In addition to the authors, other members of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network are as follow:

• Wayne State University—M. Dombrowski, Y. Sorokin, A. Millinder

• University of Pittsburgh—R. Phillip Heine, M. Cotroneo, and E. Daugherty

• University of Tennessee—W. Mabie, B. Sibai

• University of Southern California—R. Paul and Y. Rabello

• University of Alabama at Birmingham—W. Andrews, R. Copper, S. Tate, and A. Northen

• University of Cincinnati—N. Elder, T. Siddiqi, and V. Pemberton

• University of Oklahoma—G. Thurnau, J. Carey, A. Meyer

• Wake Forest University Health Sciences—P. Meis, M. Harper, M. Swain, and A. Luper

• University of Chicago—P. Jones, M. Brown, and G. Mallett

• The Ohio State University—F. Johnson, S. Meadows, and B. Collins

• University of Miami—S. Beydoun, C. Alfonso, and J. Potter

• University of Texas Southwestern Medical Center—M. Sherman

• University of Texas at San Antonio—S. Barker and O. Langer

• Thomas Jefferson University—M. DiVito and K. Smith

• The National Heart, Lung, and Blood Institute—J. Kiley

• The George Washington University Biostatistics Center—E. Thom, E. Rowland, and S. Brancolini