Preterm birth rate was higher for surrogate twin pregnancies compared to single births. Ten percent of all births were low birth weight. No births and three deaths occurred in 2009. Caroline's ten pregnancies resulted in eight live births. Its infant mortality rate stood at 203 deaths for every live births. Ratio of dead births (fetal deaths) in 1000 births was 6.9. The vital statistics provide information about live births and deaths in the population. SIDS was responsible for 0.54 deaths per 1,000 live births in the US in 2005. Maternal mortality was 150 per 100,000 live births in 2000. The infant mortality rate was 3.9 per 1,000 live births. It continues in use for registrations of births and marriages. Infant mortality was at 100 per 1,000 births in 2005. Infant mortality was 118 of 1000 live births. The infant mortality rate is 23.21 deaths/1,000 live births. Smoking bans are effective in decreasing preterm births.