This table shows the percentiles of birthweights in grams by weeks of the pregnancy and gestational age.

Percentiles of Birth Weight (grams) for gestational Age: US 1991 Single Births

Alexander et al ObGyn 1996

 

Weeks 10th%tile Average 90th%tile
20 275 412 772
 21 314 433 790
22 376 496 826
 23 440 582 882
24 498 674 977
 25 558 779 1138
26 625 899 1362
 27 702 1035 1635
28 798 1196 1977
 29 925 1394 2361
30 1085 1637 2710
 31 1278 1918 2986
32 1495 2203 3200
 33 1725 2458 3370
34 1950 2667 3502
 35 2159 2831 3596
36 2354 2974 3668
 37 2541 3117 3755
38 2714 3263 3867
 39 2852 3400 3980
40 2929 3495 4060
 41 2948 3527 4094
42 2935 3522 4098
43
2907 3505 4096
44 2885 3491 4096