Common Combinations of Pregestational Diagnosis and Pregnancy Complications.

Objective Single pregestational diagnoses have been demonstrated to be associated with pregnancy-related complications. But, the effect of multiple diagnoses is understudied. The objective of this study is to determine the most common combinations of pregestational diagnoses and to determine if specific combinations increase the risk of pregnancy-related complications. Study design We performed a cross-sectional study of the 2016 Healthcare Cost and Utilization Project's National Inpatient Sample (HCUP NIS) database. Inclusion criteria were: Diagnosis-related groups assumed to be associated with delivery, and three or fewer International Classification of Diseases, Tenth Revision (ICD-10), clinical modification codes with a prevalence greater than or equal to 0.5%, or clinically important risk factors in Bateman's co-morbidity index. Chi-squared analysis of combinations of pregestational diagnoses was performed to assess the relative risk of pregnancy-related complications. Results The 2016 database included 255,233 delivered pregnancies. The most common combinations of pregestational diagnoses involved advanced maternal age, prior cesarean delivery, obesity, and tobacco use. Most combinations did not demonstrate an increased risk for complications greater than the risk with a single diagnosis. In those with statistically significant risk, all were 3-fold or less except we noted a 4.4-fold higher risk (95% CI: 3.16-6.15) of preeclampsia in obese patients of advanced maternal age compared to patients who were only of advanced maternal age. Conclusion Our results revealed that common combinations of pregestational diagnoses, in general, do not increase the risk for common pregnancy-related complications greater than the risk with a single diagnosis. This is reassuring, given that women entering pregnancy with multiple co-morbidities are becoming more common.