In the past decades, we have observed a large increase in the number of multifetal pregnancies, which is mainly associated with the introduction of assisted reproductive techniques. Even though neonatal intensive care of very premature infants has improved significantly, the risk of mortality and long-term morbidity is still much higher among these newborns. A longer interdelivery period may re...

We analyze the relationship between prenatal WIC participation and birth outcomes in New York City from 1988-2001. The analysis is unique for several reasons. First, we have over 800,000 births to women on Medicaid, the largest sample ever used to analyze prenatal participation in WIC. Second, we focus on measures of fetal growth distinct from preterm birth, since there is little clinical suppo...

Background/Aims: Excessive gestational weight gain was known to be associated with adverse pregnancy outcomes. It increased the complications during pregnancy, delivery and postpartum period. Nevertheless, there are studies reporting the incompliance of pregnant women with recommendations of weight gain. The objectives of this study were to estimate the prevalence of high gestational weight gai...

After a long continuous decrease, the twinning and higher multifetal rates in many developed countries have increased during the last 2 to 3 decades. This change has been attributed to delayed childbearing and to increased use of subfertility treatments, particularly in women over 35 years of age. In this study we analyze how these new trends depend on changes in the effect of maternal age on t...