Association between cocaine abuse and placenta-associated syndromes: Minimizing bias using quasi-experimental approach

Background: Placenta-associated syndromes (PAS) comprise a number of abnormal conditions during pregnancy associated with placental dysfunction, and include pre-eclampsia, eclampsia, gestational hypertension, placental infarction, placental abruption, and placenta previa. Although the effects of cocaine on some components of PAS have been examined, the relationship between maternal cocaine abuse and the occurrence of PAS as a single entity has not been previously investigated.

Methods: We analyzed all singleton, live births within 20-44 weeks gestation in the state of Florida from 1998-2007 using hospital discharge data linked to birth certificate records. We determined if an association exists between maternal cocaine abuse in pregnancy and PAS using propensity scores matching techniques. Mothers who abused cocaine during pregnancy (n=5,026) were matched to controls (n=5,026) from a sample of 1,693,197 unexposed mothers.

Results: Nearly 6% of mothers in the study sample experienced a condition associated with PAS prior to matching. Women who abused cocaine were 58% more likely to have PAS when compared to women who did not (OR=1.58, 95% CI: 1.39, 1.80). Women who abused cocaine were also at elevated odds for placental abruption, placenta previa, preeclampsia, and eclampsia, with the most pronounced odds noted for eclampsia (OR=5.50, 95% CI: 1.22, 24.8).

Conclusions: These findings indicate that cocaine abuse during pregnancy is associated with the development of PAS. Further research is warranted to expand knowledge and understanding of PAS. Additionally, adequate screening of women for cocaine abuse during pregnancy is needed to provide support and intervention to improve maternal and infant health outcomes.