Related substances (GC) (Sum of peaks with a relative retention less than that of benzyl alcohol) â¤ 0.02 %: Related substances (GC) (Sum of peaks with a relative retention greater than that of benzyl alcohol) â¤ 0.20 %: Related substances (GC) (disregard limit) â¤ 0.0001 %: Benzene (GC) â¤ 0.0002 %: Chlorobenzene (GC) â¤ 0.01 %: Toluene (GC)
If you're carrying more than one baby, chances are good you'll deliver early. Twins are usually born around 36 weeks -- four weeks early. Triplets arrive at about 33 weeks, and quads often make their debut at 31 weeks.
A 23 year study conducted at four US medical centers used information from 1,612 twin pregnancies where twins were born after 28 weeks to come up with the following statistics: 1  Chances of extremely preterm (28-30 weeks): 5.3%. 2  Chances of very preterm (31-32 weeks): 8.5%.