Maternal, pregnancy and newborn characteristics in gestational hypertensive versus non-hypertensive twin pregnancies in the study population, U.S. 1995–2000.

Data presented are n (%). P values are from Chi-square tests for differences between diabetic and non-diabetic pregnancies. *SGA = Small-for-gestational-age <10th percentile, LGA = large-for-gestational-age >90th percentile, according to birth weight percentiles in non-malformation births to non-smoking mothers in the study cohort.
c One or more of the following conditions: diabetes, heart disease, acute or chronic lung disease, renal disease, genital herpes and RH sensitization.
t There were significant numbers of missing value (>10%) for smoking (n = 49494 mothers) (17.8%) and mode of delivery (101368 mothers) (36.4%). The numbers of missing for other variables were: race 0, marital status 705 (0.3%) mothers, age 0, education 3389 (1.2%) mothers, parity 12 (0.0%), other maternal illness 20721 (7.4%) mothers, preterm birth 0, low birth weight, SGA or LGA 8615 (1.5%) newborns. The rates for smoking and caesarean section, SGA, et al. are based on births with non-missing information.