Measurements and laboratory tests were performed on all participants with special focus on dietary and exercise habits and metabolic markers.Of the 728 women [ mean age 32.5 years ( SD 4.7 ) ; median parity 1 ( range 0-9 ) ] considered to be eligible for the study 235 were non-pregnant and 493 pregnant [ mean gestational age 13 ( range 6 to 18 ) weeks ] at the time of enrollment .