Maternal Weight Gain during Pregnancy

Maternal weight increases during normal pregnancy. Insufficient or excessive weight gain may pose or indicate problems for both mother and fetus.

The following table was extracted from a graph of acceptable limits for weight gain for week of pregnancy (Wolfe, 1993).

week of pregnancy	lower limit for weight gain in pounds	upper limit for weight gain in pounds
8	0.25	2.25
10	0.75	3
12	2	4
14	3.5	5.5
16	5.5	8.5
18	8	11.5
20	10.5	14.5
22	12.5	17.5
24	14.5	20.25
26	16.5	23
28	18.25	25
30	20	27
32	21.5	29
34	23	30.25
36	23.5	31.5
38	24	32
40	24	32.5

weight gain during pregnancy in pounds =

= (current body weight in pounds) - (usual body weight before pregnancy)

Lines Approximating Limits for Desirable Weight Gain (from JMP)

Lower Limit for Desirable Weight Gain

8 - 40 weeks (as a single equation)

= (0.0000276 * ((weeks)^4)) - (0.003918 * ((weeks)^3)) + (0.170149 * ((weeks)^2)) - (1.848556 * ((weeks))) + 5.9252302

8 - 16 weeks (1st of 3 segments)

= (-0.002604 * ((weeks)^3)) + (0.1517857 * ((weeks)^2)) - (1.81994 * ((weeks))) + 6.4178571

16 - 32 weeks (2nd of 3 segments)

= (0.000342 * ((weeks)^3)) - (0.041126 * ((weeks)^2)) + (2.3628096 * ((weeks))) - 23.16739

32 - 40 weeks (3rd of 3 segments)

= (0.0052083 * ((weeks)^3)) - (0.616071 * ((weeks)^2)) + (24.33631 * ((weeks))) - 297.05

Upper Limit for Desirable Weight Gain

8 - 40 weeks (as a single equation)

= (0.0000663 * ((weeks)^4)) - (0.00809 * ((weeks)^3)) + (0.3256687 * ((weeks)^2)) - (3.931889 * ((weeks))) + 16.852008

8 to 16 weeks (1st of 3 segments)

= (0.0130208 * ((weeks)^3)) - (0.379464 * ((weeks)^2)) + (4.0550595 * ((weeks))) - 12.58214

16 to 32 weeks (2nd of 3 segments)

= (-0.000789 * ((weeks)^3)) + (0.0324675 * ((weeks)^2)) + (1.1341089 * ((weeks))) - 14.77814

32 to 40 weeks (3rd of 3 segments)

= (- 4.9 * (10^(-16)) * ((weeks)^3)) - (0.040179 * ((weeks)^2)) + (3.3303571 * ((weeks))) - 36.45

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