[Impact of in vitro fertilization-embryo transfer on adverse pregnancy outcomes: A prospective cohort study]

To evaluate whether the in vitro fertilization-embryo transfer (IVF-ET) procedures could increases the risks of adverse pregnancy outcomes (APOs) in offspring.
 Methods: A hospital-based prospective cohort design was conducted, which contained a control group of singleton pregnancies with indicators of subfertility who were still conceived naturally after using simple medical treatment (e.g. minimal medical intervention or ovulation induction), and an exposure group consisted of singleton pregnancies who had a history of infertility and IVF-ET treatment. All factors different between two groups in the univariate analysis were included in the multivariable logistic regression to evaluate the independent effect of IVF-ET procedures themselves on APOs.
 Results: After controlling for confounding factors by using multivariate logistic regression analysis, our results showed that pregnancies after IVF-ET experienced a higher risk of preterm birth (OR=1.28, 95% CI 1.05 to 1.56), low birth weight (OR=1.69, 95% CI 1.27 to 2.31), perinatal mortality (OR=5.33, 95% CI 2.44 to 11.81), and congenital malformations (OR=1.83, 95% CI 1.12 to 2.94).
 Conclusion: The IVF-ET operational factors may increase the risk of APOs.