[Impact of fetal mortality on prematurity in Argentina: A population based study]

Background: It has been observed that the increase in preterm births was accompanied by a decrease in fetal mortality.

Objective: To evaluate the relationship between fetal mortality and prematurity in Argentina.

Methods: Ecological design. The population included all live births and fetal demise in Argentina between 2003 and 2013. Outcomes: total fetal mortality rate (TFMR), fetal mortality rate by birth weight, fetal mortality rate, neonatal mortality rate, perinatal mortality rate, trends in fetal mortality rates specific for gestational age (GA), and prematurity (<37+ 0 weeks). Independent variables: age (<19 and > 35 years), education <8 years, with partner, parity 1 and > 4, multiple pregnancy and birth rate. Statistical analysis: linear regression analysis adjusted for covariates.

Results: TFMR showed an annual reduction of 0.18 per thousand births that decreased with the increase of GA, being the largest reduction below 28+0 weeks (68%), while prematurity increased 0.07% per year, being the largest increase (0.75%) between 32+0 and 36+6 weeks. Linear regression model showed an inverse relationship between TFMR and prematurity (adjusted R2 0.76, p = 0.010), being the highest between 32+0 and 36+6 weeks (adjusted R2 = 0.98, p < 0.001).

Conclusions: The reduction in fetal mortality was associated with the observed increase in preterm births in Argentina.