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Department of Statistics Colloquium

Statistical Methods for Observational Studies in Pregnancy Outcomes

Tuesday, June 4, 2013
  3:45–4:45 p.m.

Location: Olmsted Hall 420
  Parking Information

Category: Lecture


Ronghui (Lily) Xu
Department of Family and Preventive Medicine
and the Department of Mathematics
UC San Diego

Statistical Methods for Observational Studies in Pregnancy Outcomes


We describe the efforts to study effects of drug, vaccine, and other substances on pregnancy through pregnancy registries. One of the features of pregnancy outcomes is multivariate, and there has been increasing effort to follow the children longitudinally over time. We propose to model the longitudinal data using random effects, and leave the joint distribution of the multiple outcomes unspecified. A main challenge in the regression analysis of multivariate data is the fact that the different outcomes are measured on different unknown scales, and we extend existing methodology in the literature for cross-sectional data to the longitudinal setting. Another feature of such data is left truncation, which affects outcomes such as spontaneous abortion or preterm delivery. Left truncation leads to biased sampling. In addition, a substantial portion of the women will not have the events of interest, a portion termed ‘cured’ in survival analysis.  Finally, a window, instead of the exact date, of a woman’s event is sometimes all that is available.  We describe our work aimed to account for these features of pregnancy outcomes data.

Ph.D., Applied Mathematics, 1996, UC San Diego
MS, Applied Mathematics, UC San Diego

Dr. Xu worked for one year as a postgraduate researcher at the UCSD Cancer Center and the Department of Mathematics before taking up an Assistant Professorship in 1997 in the Department of Biostatistics, Harvard School of Public Health and the Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute in Boston, MA. She returned to UCSD in 2004 and is now Professor in the Department of Family and Preventive Medicine and the Department of Mathematics. She was recently selected as a 2013 Fellow of the American Statistical Association

Open to: General Public
Admission: Free
Sponsor: Statistics Department

Contact Information:
Paula Lemire
(951) 827-3774