THE BASAL METABOLISM BEFORE, DURING, AND AFTER PREGNANCY.

BY IRENE SANDIFORD AND THEODORA WHEELER.

(From the Sections on Clinical Metabolism and Obstetrics, Division of Medi- cine, Mayo Clinic and the Mayo Foundation, Rochester.)

(Received for publication, September 15, 1924.)

Several observers have reported that the total energy produc- tion of the normal pregnant woman undergoes little or no change in the beginning of gestation, but that during the latter part of pregnancy, there is a gradual and significant increase. We have studied the heat production in one woman before conception, during pregnancy and the puerperium, and for 4 months after the cessation of lactation and the reestablishment of menstruation, a total period of 17 months. Our observations, as will be pointed out in detail, confirm the finding of a definite increase in the total heat production during the latter part of pregnancy, but we believe that our data, as well as those of other observers, show that the rate of metabolism of a unit mass of the mother’s tissue undergoes no material change, and that the increase in the total heat production may be accounted for by the increase in the amount of active protoplasmic tissue, which is composed chiefly of the fetus, with a small amount of new and accessory tissue of the mother.

The subject of this study was a normal multipara (para IV), aged 34 years. The last menstrual period before pregnancy occurred March 3, 1923, and parturition took place December 7, making a period of gestation of approximately 10 months’ dura- tion. The pregnancy was normal, clinically, and examinations of the urine were negative. The blood pressure readings taken at the time of each metabolism test were low normals. Three or four times during the 5th and 6th months there was slight nausea in the afternoon. This symptom had been present in diminish- ing degree in each of the four pregnancies. Vomiting occurred

329

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

330 Basal Metabolism in Pregnancy

but once, an afternoon in the 5th month (July 10, 1923) after the patient had eaten raspberries on an empty stomach. From the beginning of the 5th through the 7th lunar month, there were occasional days of lassitude, when the subject felt drowsy and became exhausted on the slightest exertion. Except for this rather indefinite disability, pressure pains, and some edema of the ankles during the last month, the subject was in very good health during the pregnancy. Confinement occurred December 7, 1923. The baby girl weighed at birth 3.6 kilos, the weight of the fluid was 0.9 kilo, and of the blood and placenta 1.8 kilos. Lactation was of approximately 4 months’ duration. Five feedings were given every 24 hours, and the amount of milk pro- duced increased gradually from 174 gm. at 3 days postpartum to 623 gm. on the 23rd day. The supply, however, was not ade- quate for the baby, and complementary feedings were begun at the end of the 1st week. In the 4th week of the puerperium, the mother contracted an infection of the upper respiratory tract which was severe for about 5 days (January 5 to 10, 1924) and did not entirely clear up for 2 weeks. During this time the average daily amount of milk was only 439 gm. During the 6th week there was a daily average of 504 gm., then the amount gradually diminished. Because the baby persistently refused to nurse, she was weaned in the 16th week. The mother led an active, normal life, and no attempt was made to regulate the diet or the amount of exercise.

The metabolism was determined with the subject under standard postabsorptive conditions after complete rest in bed for 3 hour. As the subject was calm and quite undisturbed by the numerous metabolism tests, and cooperated fully at all times, the results are satisfactory from this standpoint. For the determination of the basal metabolic rates, the expired air was collected in a gasometer by means of a mask and valves, and analyzed in. duplicate in the Haldane gas analysis apparatus. All readings were taken in duplicate by two observers, and the calculations checked by two persons. The details of the tech- nique need not be reviewed here since they have been fully described by Boothby and Sandiford.

Complete data on this study are given in Tables I and II. In Chart 1 are plotted the total calories for each hour (Curve D),

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

CHAR

T 1.

Ba

sal

met

aboli

sm

findin

gs

befo

re,

durin

g,

and

afte

r pr

egna

ncy.

The

subje

ct,

a wo

man

, ag

ed

34

year

s, he

ight

160

cm.

Curve

A

repr

esen

ts th

e ca

lories

for

ea

ch

kilo;

Cu

rve

B,

the

basa

l m

etab

olic

rate

ca

lculat

ed

durin

g th

e co

urse

of

pr

egna

ncy,

by

divid

ing

the

tota

l ca

lories

ea

ch

hour

by

th

e su

m of

th

e su

rface

ar

ea

of

the

mot

her

and

fetu

s, an

d co

m-

parin

g th

e re

sult

obta

ined

with

th

e Du

Bo

is no

rmal

of

the

mot

her,

36.5

ca

lories

. Cu

rve

B’

repr

esen

ts th

e ba

sal

met

aboli

c ra

te

calcu

lated

in

th

e us

ual

met

hod,

us

ing

the

Du

Bois

surfa

ce

area

an

d no

rmal

stand

ards

. Cu

rve

C is

the

calor

ies

for

each

squa

re

met

er

each

ho

ur

deriv

ed

for

the

cour

se

of

preg

nanc

y as

jus

t de

scrib

ed

for

Curve

B.

Cu

rve

C’

repr

esen

ts th

e ca

lories

for

each

sq

uare

m

eter

ea

ch

hour

, ob

taine

d by

di

vidin

g th

e to

tal

calor

ies

each

ho

ur

by

the

Du

Bois

surfa

ce

area

ob

taine

d by

us

ing

the

tota

l we

ight

of

mot

her

and

fetu

s in

th

e us

ual

man

ner.

Curve

D

rep

rese

nts

the

tota

l ca

lories

for

ea

ch

hour

.

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

TABL

E I.

Basa

l M

etab

olism

Fi

ndin

gs

befo

re

and

duTi

ng

Preg

nanq

.

Subje

ct:

A wo

man

, ag

ed

34

year

s, he

ight

16

0 cm

.

$i

g - kg.

i2.E

i2

.i j5

.i i5

.2

i5.5

i5

.e

id.1

i6

.5

i6.9

i7

.1

i7.2

i7

.7

17.6

17

.9

i a - “F.

38.C

38

.f 38

.E

38 f

a8

.4

j8.4

J8

.4 )8

.E

j8.2

b8

.4

b8.1

18

.C

b8.6

j8

.2

-

- 4 - 70

0.80

63

0.

88

66

0.82

67

0.

81

73

0.80

71

0.

81

65

0.82

70

0

80

66

0.82

71

0.

83

70

0.83

73

0.

80

65

0.80

70

0.

80

-

14

1 - --

_ -

- -_ P

-

- 6

8 15

5.3

4.0

5.1

5.0

1.7

5.1

2.3

1.5

2.5

2.7

1.8

3.6?

3.

5 t.4

‘er c

m

-3 -7

-3

-4

-5

-4

-11 -6

-11

-10

-12

-21?

-8

-6

er cm

-3

’ -7

: -3

;

-4’

-5’

-4’

-11’ -6

’ -1

1’ -1

01

-14

-10 -8

R.em

arks

. Da

te.

is.89

Feb.

21

“

27

Apr.

23

u 30

Ma

y 7

‘l 18

“

28

June

4

“ 13

“

20

“ 27

Ju

ly 4

“ 11

“

18

7.9

5.7

8.9

8.5

8.3

9.0

4.5

8.4

5.3

5.5

4.0

8.7?

6.

9 5.

4

3 3 3;

3!

31

3i

3:

3‘

3:

3:

3:

21

3:

31

-

Mar.

3.

Begi

nnin

g of

m

en-

strua

l pe

riod.

1.69

Ju

ly 4.

Le

ak

in

mask

. 1.

70

1.70

*Sam

e as

in

Co

lum

n 8,

be

caus

e th

e ma

ss

of

the

fetu

s wa

s to

o sm

all

to

justify

re

calcu

lation

.

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

July

25

67

.5

97.8

68

0.

75

56.1

33

.0

-9

Aug.

1

67.0

98

.1

72

0.78

54

.4

32.2

-1

2 “

8 68

.5

98.4

70

0.

86

59.1

34

.5

-5

“ 15

68

.5

98.6

80

0.

87

58.8

34

.4

-5

Oct

. 10

74

.9

98.2

79

0.

85

64.5

36

.4

0 “

17

74.5

97

.9

83

0.94

67

.4

38.1

+5

“

24

74.3

97

.4

85

0.87

65

.6

37.1

+2

“

31

74.9

98

.1

85

0.86

67

.9

38.3

+5

N

ov.

7 75

.3

98.0

83

0.

82

68.0

38

.2

$5

“ 13

75

.8

96.8

90

0.

88

66.8

37

.5

$3

u 16

75

.8

96.8

81

0.

86

68.4

38

.4

+6

“ 20

76

.2

98.2

83

0.

83

67.2

37

.5

+4

“ 23

76

.3

98.0

83

0.

84

74.3

41

.5

4-14

=

24

76.5

98

.0

93

0.88

70

.1

39.2

+8

80

0.

90

70.5

39

.4

$8

“ 27

76

.1

97.9

91

0.

77

72.1

40

.3

t11

89

0.78

73

.0

40.8

i-1

3 u

28

76.0

96

.8

92

0.84

69

.8

39.0

+7

97

.7

90

0.86

72

.4

40.5

t1

1 “

29

76.5

97

.6

81

0.86

69

.6

38.9

+7

82

0.

83

71.1

39

.7

+9

“ 30

76

.3

98.2

89

0.

83

70.2

39

.0

+7

92

0.85

72

.8

40.4

4-

11

Dec

. 1

76.3

98

.2

95

0.87

70

.2

39.0

+7

90

0.

82

73.4

40

.8

t12

I<

3 76

.3

97.6

74

0.

86

72.6

40

.3

t10

“ 4

76.2

97

.8

90

0.88

67

.9

37.7

$4

“

5 76

.2

97.8

80

0.

86

71.5

39

.7

+g

“ 6

76.9

97

.8

80

0.85

71

.2

39.5

$8

‘t

7 77

.1

98.1

83

0.

84

70.9

39

.4

+8

0.05

0.

3 67

.2

1.70

1.

75

0.06

0.

4 66

.6

1.69

1.

75

0.07

0.

5 68

.0

1.71

1.

78

0.07

0.

6 67

.9

1.71

1.

78

0.15

1.

7 73

.2

1.76

1.

91

0.16

1.

9 72

.6

1.75

1.

91

0.16

1.

9 72

.4

1.75

1.

91

0.17

2.

1 72

.8

1.75

1.

92

0.20

2.

7 72

.6

1.75

1.

95

0.20

2.

7 73

.1

1.76

1.

96

0.22

3.

0 72

.8

1.75

1.

97

0.22

3.

0 73

.2

1.76

1.

98

0.23

3.

3 73

.0

1.75

1.

98

0.23

3.

3 73

.2

1.76

1.

99

0.23

3.

3 72

.8

1.75

1.

98

0.23

3.

3 72

.7

1.75

1.

98

0.25

3.

6 72

.9

1.75

0.25

3.

6 72

.7

1.75

0.25

3.

6 72

.7

1.75

0.25

3.

6 72

.7

1.75

0.

25

3.6

72.6

1.

75

0.26

3.

9 72

.3

1.75

0.

26

3.9

73.0

1.

75

0.26

3.

9 73

.2

1.76

2.00

2.00

2.00

2.00

2.

00

2.01

2.

01

2.02

- 32

.1

31.1

33

.2

33.0

33

.8

35.3

34

.3

35.4

34

.9

34.1

34

.7

33.9

37

.5

35.2

35

.4

36.4

36

.9

35.3

36

.6

34.8

35

.6

35.1

36

.4

35.1

36

.7

36.3

34

.0

35.6

35

.4

35.1

-12

-15 -9

-9

-7

-3

-6

-3

-4

-6

-4

-7

+3

-4

-3 0

+1

-3

+1

-4

-2

-4 0

-4

$1 0

-7

-2

-3

-4

Dec.7

. Co

nfine

dat4

.00

p.m

. E

” ,lj

/,

,,*

, ,,

/,,

.,”

.,

,//

,,

. ,,

*,

. -,

>

,,*

,.,,

, -,

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

334 Basal Metabolism in Pregnancy

TABLE II.

Basal Metabolism Findings during 6 Months Following Delivery.

Date. . ;i .bo

s ___-

19M kg.

Dec. 8 “ 10 69.: 3

97.1 3 97.1 3

“ 11 68.1 L

“ 12 67.: 5

98.t I

97.t 3

“ 13 67.: 3 97.: s

3 3 1 3 3 D 0 6 9 6 1 4

“ 14 67.1 “ 15 67.1 “ 17 68.f “ 18 67.! “ 19 67.! “ 20 68.t “ 21 68 .I “ 22 68.1 “ 24 68.’ “ 26 68 .I “ 28 69. “ 31 69. 1924

Jan. 2 69. “ 7 68. “ 9 68. “ 11 69. “ 14 68. “ 16 69. “ 19 68. (‘ 21 69. “ 23 69. “ 25 69. “ 28 70. “ 30 70.

Feb. 1 70. “ 4 68. “ 6 69. “ 8 68.

0 6 9 0 6 1 8 1 9 6 1 4 4 9 5 8

-

97.1 8 98. 1 97.1 8 97.’ 8 97 .’ 8 97. 9 98. 0 98. 0 98. 0 97. 4 98. 0 98. 6

99. 2 98. 1 97. 7 97. 0 97. 4 97. 8 97. 3 97. 4 98. 0 97. 4 97. 2 97. .2 97 .5 97 .8 97 .6 97 .2

-

- Y-

Dec. 7, Delivery of baby weighing 3.6 kg.

67 0.8( 74 0.84 73 0.8: 80 0.8: 80 0.8: 78 0.8t 77 0.84 78 0.91 77 0.8! 74 0.9‘ 74 0.9: 63 0.91 65 0.8! 63 0.8! 64 0.8! 63 0.91 59 0.8 58 0.9: 55 0.8, 60 0.8 66 0.8

59.2 34.4 -t 50.2 35.0 -4 59.5 34.6 --! 50.5 35.4 -I 59.8 35.0 -1 59.7 35.2 -: 59.9 35.3 -t 57.2 33.7 -: 58.4 34.3 -t 59.0 34.7 -! 57.8 34.0 --: 56.6 33.3 --I 55.6 32.7 -l( 55.4 32.6 --II 56.1 33.0 -! 55.1 32.4 -1 53.8 31.6 -1: 55.2 32.3 -1’ 54.6 31.9 -1’ 56.2 32.7 -11 57.4 33.4 -

Dec. 21. Discharged from hospital.

76 0.7 69 0.8 64 0.8 56 0.7 67 0.8 65 0.8 70 0.8 59 0.8 61 0.8 62 0.8 62 0.86 65 0.85 64 0.83

60.4 35.3 - 56.7 33.1 - 53 9 31.5 -1 52.1 30.3 -1 54.7 32.0 -1 56.2 32.7 -1 56.7 33.1 - 57.5 33.5 - 56.8 33.0 - 57.1 33.2 - 59.7 34.7 - 58.71 34.1 -

Jan. 2. Pharyngitis. (‘ 7. “ “ g “

“ 11. Asleep.

157.51 33.41 -8)

il ~~~~::I ~~~~! ,“,1 57 0.80156.2 32.7 -10 Feb 6 Beginning of men-

sirual period. 4

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

I. Sandiford and T. Wheeler 335

TABLE ll-~onduded.

6 4 6

2

z I a

2 ‘i i

-,;. jg

Date. 2 3 oi ‘;a . 3

2 g

.B 2 MC $4 33% .F9 Remarlrs.

g g 82 2s

.i:Bl !g

sic33

23 sg

12 k d’ g” d”’ p1 ----_--__

19th kg. OF. Per cent

Feb. 11 69.1 97.4 57 0.8554.5 31.7 -13 “ 13 68.9 98.0 58 0.8455.5 32.5 -11 “ 15 68.9 96.0 56 0.8354.7 32.0 -12 “ 18 69.1 97.4 65 0.8159.2 34.6 -5 “ 20 69.4 98.0 54 0.8253.1 31.1 -15 Doaing. “ 22 69.6 97.6 57 0.8354.6 31.8 -12 “ 25 69.5 97.4 58 0.8654.4 31.6 -13 “ 27 69.7 97.5 62 0.8054.4 31.8 -12 u 29 70.0 97.2 60 0.8557.1 33.2 -9

Mar. 3 70.7 97.3 53 0.8251.9 30.0 -18 Asleep. ‘I 5 70.2 97.3 64 0.8057.9 33.7 -7 “ 7 70.2 96.9 63 0.8359.0 34.1 -6 “ 10 70.4 98.6 68 0.8357.3 33.1 -9 Mar. 11. Beginning of men- “ 12 70.4 97.6 59 0.8454.6 31.6 -13 strual period. “ 14 69.5 97.4 62 0.8254.0 31.4 -14 “ 17 69.3 97.8 59 0.8156.4 32.8 -10 “ 19 69.6 97.7 64 0.7357.2 33.3 -8 “ 21 69.1 97.6 63 0.7856.1 32.6 -10 “ 24 68.5 97.8 72 0.7257.1 33.4 -8 “ 27 68.8 97.7 60 0.7956.3 32.9 -10 “ 31 67.8 98.2 61 0.7955.6 32.7 -10

Apr. 3 68.8 98.6 62 0.8451.3 30.0 -18 Apr. 4. Beginning of men- “ 9 68.2 97.8 54 0.7953.1 31.0 -15 strual period. “ 11 68.2 98.0 60 0.8051.9 30.4 -16 Apr. 11. Very drowsy. “ 14 67.8 97.7 61 0.8154.4 32.0 -12 “ 16 68.1 97.8 64 0.7854.3 31.7 -13 “ 21 68.2 98.2 58 0.7855.9 32.7 -10 “ 23 67.9 98.5 61 0.8055.8 32.9 -10 “ 28 67.7 97.4 59 0.8352.1 30.6 -16 Apr. 27. Beginning of men- “ 30 68.0 97.9 60 0.8452.9 30.9 -15 strual period. Drowsy.

May 5 67.5 97.8 60 0.7754.1 31.8 -12 May5. Very tired. “ 7 68.0 97.6 63 0.8153.4 31.6 -13 “ 12 67.2 97.9 61 0.7956.1 33.0 -9 ” 14 67.6 98.4 64 0.8254.1 31.8 -12 “ 19 67.2 97.8 64 0.8259.0 34.9 -4 May20. Beginning of men- “ 21 67.5 97.6 60 0.8156.4 33.2 -9 strual period. “ 26 66.8 97.8 59 0.7853.7 31.8 -12 “ 28 67.5 97.6 65 0.8154.5 32.1 -11

June 2 67.2 98.0 61 0.7560.2 35.4 -3 June 2. Restless night. “ 4 67.1 98.2 59 0.7956.2 33.1 -9

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

336 Basal Metabolism in Pregnancy

2 4 6 8 10 2 4 6 Lunar Months

CHART 2. Basal metabolism findings averaged according to lunar months before, during, and after pregnancy. The subject, a woman, aged 34 years, height 160 cm. Curves A, B, B’, C, C’, and D represent the averages for each lunar month of the corresponding Curves A, B, B’, C, C’, and D in Chart 1.

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

I. Sandiford and T. Wheeler 337

the calories for each square meter (Curve C’) and each kilo (Curve A) each hour, and the basal metabolic rate (Curve B’), calculated in the ordinary manner, using the Du Bois standards. In addition are plotted the two curves, C and B, representing calories for each square meter each hour, and basal metabolic rate, respectively, calculated according to the new method de- scribed in this study. The averages for each lunar montSf of each of these curves, before and after pregnancy, are plotted in Chart 2. The only observation omitted from the average was that of July 4, which was so far below the level of any other determina- tion that an experimental error seemed probable, although on that date the subject was very weak and nearly fainted. The metabolism studies were begun during the latter part of February, 1923, and two control periods previous to conception were ob- tained. On account of the subject’s absence from town, no determinations were made during the 1st month, and only one determination during the 2nd lunar month of pregnancy, From the 3rd to the 9th lunar month, inclusive, the metabolism was determined once a week, except during the 7th month, when the subject was again out of town. During this month, there also occurred 2 days of great lassitude (September 4 and 5). On the 4th, in particular, there was drowsiness with marked subjective disinclination for any exertion; this was the only day spent in bed during the entire pregnancy. The subject at the time was near New Haven, and through the courtesy of the Yale Meta- bolic Laboratory a metabolic rate was made September 6. This test was made in duplicate, with results of -19 and - 18 per cent. Rates taken at the same laboratory 9 and 25 days later were - 12 and - 2 per cent, respectively, each being the average of two observations varying within 5 per cent of each other. In the beginning of the 10th month, three determinations were made each week, and from November 24 to December 3 the rates were taken daily (except Sunday) in duplicate, and from December 3 until confinement, December 7, single daily determinations were made. From December 8 to 14, duplicate determinations were made daily, then single determinations daily until December 24, when the metabolism was observed three times a week until March 24; after that two determinations were made each week until the end of the study, 6 months after delivery.

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

338 Basal Metabolism in Pregnancy

As can be seen in Chart 2, which represents the average for each lunar month, there was less than a f3 per cent monthly variation from the average of the total energy production during the first 6 months of pregnancy. During the 8th month there was a gradual increase in the total energy production, and the peak was reached during the last month. The height of the latter was somewhat influenced by fetal movements which in a few of the periods were quite marked, as can be seen in Chart 1 by the greater irregularity in the daily determinations of the last month of pregnancy. Up to November 23, movements of the fetus during the metabolism tests had scarcely been per- ceptible. On that day there were energetic, and almost contin- uous, fetal movements during the rest period, as well as during the test itself. As Chart 1 shows, the metabolism on that day was the highest obtained. The influence of the fetal move- ments on the heat production is, therefore, very evident. Dur- ing each subsequent test, a rough estimate of the duration and intensity of the fetal movements was made by the subject sig- nalling to the observer by slightly bending one finger when the fetal movements were very mild, two fingers when they were more vigorous, and subsequently straightening the fingers when the fetus was again quiet. A study of these records shows that there is a slight increase in the metabolism; roughly corresponding to the intensity and duration of the fetal movements.

On the day of delivery the subject’s weight had increased 23 per cent over that during the control period, and there was an increase of 25 per cent in the total heat production ; hence there was practically no change in the calories for each kilo. Although there was an increase in the total heat production from 56.8 calories, during the control period, to 59.2 calories on the morning following delivery, as shown in Chart 1 and in Tables I and II, the basal metabolic rate, which takes into considera- tion variations in weight, on the morning following delivery was -6 per cent, corresponding to the patient’s basal rate of -5 per cent before pregnancy, which is confirmatory evidence that the mother’s rate of heat production for each unit mass of tissue remained unchanged during pregnancy, and that the increases in total heat production were due to the metabolism of the new tissue.

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

I. Sandiford and T. Wheeler 339

Basal metabolism determinations were made for 6 months after delivery and, as shown in Chart 1 and in Table II, the basal metabolic rates show fluctuations of the same magnitude as reported by Benedict, by Blunt and Dye, by Sturgis, and others. The fluctuations are of slight magnitude, and are not correlated with the menstrual cycle. The total heat production and basal metabolic rates, when averaged for each lunar month, show a slight decrease, so that 4 months after delivery the metabo- lism was approximately 8 per cent lower than before pregnancy. This may be accounted for by the less active life of the mother, necessitated by nursing, especially since the metabolism tended to return to normal during the next 2 months as her usual activi- ties were resumed following the cessation of lactation. Our data confirm the findings of Hasselbalch and of Carpenter and Mur- lin that lactation in the human being is not associated with an in- crease in heat production, and that, therefore, the conversion of the mother’s food into milk does not involve a material loss of energy. Lusk points out that the rearrangement of food mate- rials in the preparation of milk depends on hydrolytic changes and syntheses which involve hardly any therm01 reactions.

The experiments of Magnus-Levy, Zuntz, Hasselbalch, Car- penter and Murlin, Root and Root, Rowe, Alcott, and Mortimer, and our report show beyond question that the total energy pro- duction of a pregnant woman increases slightly, beginning at the middle of gestation, and finally reaching a maximum of approx- imately 20 per cent above her basal value before pregnancy. However, we do not believe that there is definite evidence that the rate of heat production of a unit mass of tissue of the normal human organism is materially changed during pregnancy, but rather that such increases as occur represent the heat produc- tion of the newly formed protoplasmic tissue, composed largely of the fetus, and to a less extent of maternal tissue.

Carpenter and Murlin, using the respiration calorimeter, have shown that the energy production of mother and child suffers no deflection at birth, and that, therefore, the heat production of the fetus at term is practically uninfluenced by birth (Table III). In consequence, the fetus, as well as the baby after birth, should be regarded as a being independent of the mother, and its heat production calculated on its own surface area, which is propor-

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

340 Basal Metabolism in Pregnancy

tional to its own active protoplasmic mass before and after delivery. We have made a series of such calculations which are summarized in Table I. If the weight values of the fetus at different months of pregnancy are plotted on logarithmic paper, they are found to lie on a straight line, as shown by Sandi- ford. Therefore, it is .possible to read, with a fair degree of accuracy, the probable weight of the fetus at any period of preg- nancy, and the surface area of the fetus can then be readily cal- culated by Lissauer’s formula, or read directly from Chart 1 in the preceding paper by Sandiford. The, weight of the mother alone during the course of pregnancy can be obtained, therefore, by subtracting the estimated weight of the fetus from that of the mother and fetus. From this estimated weight of the mother,

TABLE III.

Heat Production of Mother and Boby before and after Delivery. Data of Murlin and Carpenter using the respiration calorimeter.

Case No.

1 61.2 53.9 2 69.3 59.6 3 69.8 60.4

1 2 3

-

_ .

-

4

her surface area can be determined from the Du Bois surface area charts by the usual method. If the surface area of the fetus is added to the surface area of the mother thus obtained, and the total calories for each hour are divided by the sum of the surface area of the mother and of the fetus, figures are obtained which represent the heat production of a unit mass of active protoplasmic tissue. The calories for each square meter of body surface thus obtained are plotted as Curve C in Charts 1 and 2, and show that there is no essential change in the rate of heat production of a unit mass of active protoplasmic tissue in the human being as a result of pregnancy. The variation in the calories for each square meter of body surface, using the com-

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

I. Sandiford and T. Wheeler 341

bined surface area of the mother and of the fetus from the Du Bois normal of the mother, 36.5 calories, is plotted as Curve B in Charts 1 and 2, and shows fluctuations of only small magni- tude, even at the termination of pregnancy. The small mass of the fetus compared to that of the mother allows us to use the standard of the mother without a significant error, as is shown here. The calculation separately of the surface area of the mother and fetus, and the use of the sum of these surface areas to divide into the total calories is correct if, as maintained by Boothby and Sandiford, the relationship between the surface area and basal standard heat production rests on the proposition that the surface area is proportional to the mass of active pro- toplasmic tissue. Such a calculation would, of course, be invalid if the surface area law depended on Newton’s law of cooling. As these authors point out, the latter conception has been abandoned by nearly all users of the surface area method, and the view seems to be very generally accepted that the surface area is the most exact method at present available‘for estimating the ratio between different individuals of the mass of active protoplasmic tissue.

The validity of this method of calculation can be checked in a very convincing manner as follows: If the average for the 3 days after confinement, of the calories for each square meter each hour (34.9) of the mother is multiplied by the average estimated surface area (1.75) of the mother alone for the 4 days before confinement, the total calories (61.1) of the mother alone just before confinement are obtained. If this figure (61.1) is subtracted from the average of the total calories of mother and fetus for the 4 days before delivery (70.4), the remainder (9.3) may be assumed to represent the total calories of the fetus. Furthermore, if the total calories of the fetus thus calculated are divided by the surface area (0.26) of the baby at birth, which corresponds with the estimated surface area of the fetus for the 4 days before delivery, the heat production of the fetus is shown to be 35.8 calories for each square meter each hour, or 859 calories for 24 hours, which agrees satisfactorily with Talbot’s findings (650 to 800 calories) of the metabolism of new-born infants. On the assumption that the heat production of a unit mass of fetal tissue will remain constant throughout fetal life, by multiplying

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

Basal Metabolism in Pregnancy

the heat production for each square meter of body surface each hour by the surface area of the fetus corresponding to its esti- mated weight, the total calories each hour for the fetus are ob- tained for the various months. If this latter figure is subtracted from the total calories of mother and fetus, the total calories of the mother alone are obtained, and when divided by the esti- mated surface area of the mother, the calories for each square meter of body surface of the mother alone are practically the same as those plotted as Curve B, obtained by the other method of calculation. Therefore, almost identical figures for the heat production of the mother are obtained by both our methods of calculation, and also the heat production of the fetus, when cal- culated according to these methods, is what might be expected from the data of Benedict and Talbot. The consistency not only of our results, but of those of other observers, is striking, es- pecially if it is remembered that a very slight variation in the heat production of the mother, because of her relatively large mass, would make absolutely impossible figures for the heat production of the fetus.

Root and Root have reported one case in which the heat pro- duction was carefully determined from the 4th month of preg- nancy to delivery with occasional rates thereafter, and their findings, as shown in Chart 3, are strikingly similar to ours. The total energy production of the mother was practically un- changed during the early months of pregnancy, but there was a gradual increase beginning with the 8th month, and the peak was reached during the last month. In this particular case, the total heat production had reached its highest level 12 days be- fore confinement, and showed an increase over the basal rate of February 9, of +19 per cent. 3 weeks after delivery the total calories had decreased below the pati,ent’s basal rate of February 9, but, as in the case of our subject, this is probably the result of a less active life. Here, again, the fact that lactation is unac- companied by an increased heat production is significant. If the data of Root and Root are recalculated by our method, the heat production of the mother for each unit mass of active pro- toplasmic tissue remains unchanged throughout the course of pregnancy, as can be seen by Curves B and C in Chart 3. If the heat production of the baby is calculated, it is found to be

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

CHART 3. Basal metabolism findings averaged according to lunar months during and after pregnancy. Data of Root and Root. Curve A represents the calories for each kilo; Curves B and C, the basal metabolic rate and calories for each square meter, respectively, calculated according to our method. Curves Wand C’represent the basal metabolic rates and calories for each square meter calculated in the ordinary manner. Curve D repre- sents the total calories for each hour.

343

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

Basal Metabolism in Pregnancy

0 2 4 6 8 10 Lunar Months

CHARTS. Basal metabolism findings averaged according to lunar months before and during pregnancy. Data on Zuntz’s Case B. Curve A repre- sents the calories for each kilo; Curve B, the calories for each square meter, calculating the data according to our method, using the Meeh surface area formula for the mother and the Lissauer formula for the fetus; Curve B’ the calories for each square meter, using the Meeh surface area formula and the weight of the pregnant mother in the usual manner. Curve c” represents the total calories for each hour.

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

I. Sandiford and T. Wheeler 345

661 calories for each square meter every 24 hours, a value con- sistent with that found by Talbot for new-born infants (650 to 800 calories). Joslin found no abnormalities in the metabolism

CHART 5. Basal metabolism tidings averaged according to lunar months before and during pregnancy. Data on Zuntr’s Case C. Curve A repre- sents the calories for each kilo; Curve B, the calories for each square meter for each hour, calculated according to our method, using the Meeh surface area formula for the mother and the Lissauer formula for the fetus. Curve B’ represents the calories for each square meter, calculated according to the usual method, using the surface area obtained by Meeh’s formula from the weight of the pregnant mother.

of these diabetic patients during pregnancy either as compared with normal women in similar condition or with two patients

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

-02468 Calendar Months

CHART 6. Basal metabolism before and during pregnancy. Data on Magnus-Levy’s case averaged according to calendar months. Curve A represents the calories for each kilo; Curve B, the calories for each square meter calculated according to our methqd, using the surface area of the mother derived by Meeh’s formula and the surface area of the fetus by the Lissauer formula. Curve B’ represents the surface area derived by the usual method, using the Meeh formula. Curve C represents the total calories for each hour.

346

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

Weeks CHARTS. Baaal metabolism findings averaged by 2 week intervals during

and after pregnancy. Data of Rowe, Alcott, and Mortimer, Case 13, Series II. Curve A represents the calories for each kilo; Curves B and C are, respectively, the basal metabolic rate (Du Bois standards) and calories for each square meter each hour calculated according to our method. Curves B’ and C’ are, respectively, the basal metabolic rate (& Bois standards) and calories for.each square meter each hour calculated in the usual manner. Curve D is the total calories each hour.

347

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

e , , , , , , , , , , , , , , 24 20 i6 12 8 4 0 4

Weeks CHAI(T 8. Basal metabolism findings averaged for 2 week intervals

during and after pregnancy. Data of Rowe, Alcott, and Mortimer, Case 28, Series I. Curve A represents the calories for each kilo. Curves B and C represent, respectively, the basal metabolic rate (Du Bois standards) and calories for each square meter each hour, calculated according to our method. Curves B’ and C’ are, respectively, the basal metabolic rate (Du Bois standards) and calories for each square meter each hour calculated according to the usual method. Curve D is the total calories each hour. Curve E represents the average curve for the total calories each hour of the twenty-five cases of Series I of Rowe, Alcott, and Mortimer as given in their Chart 3.

348

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

I. Sandiford and T. Wheeler 349

compared with themselves at an earlier period when not pregnant and yet diabetic.

We have also recalculated the data of Zuntz’s Cases B and C, and of Magnus-Levy’s case, since these three cases were ob- served for a considerable time before conception, and during pregnancy. The results are plotted in Charts 4, 5, and 6, re- spectively, and show a very definite increase in the total energy production, the maximal occurring during the last month of pregnancy. In one of these cases (Curve C, Chart 5)) there is apparently a decrease of about 8 per cent in the heat production of a unit mass of protoplasmic tissue, while in two, an increase of 10 or 11 per cent (Curve C, Charts 4 and 6) is apparent at the termination of pregnancy. However, the effect of fetal move- ments must be seriously considered as producing a greater part, if not all of this increase, because, as can be seen by a detailed study of the observations in our case; there was a marked increase in total heat production whenever there were noticeable fetal movements during the period of observation. Furthermore, as the height of the subjects of Zuntz and of Magnus-Levy is not known, it was necessary to resort to Meeh’s surface area formula instead of the Du Bois, which may also in part account for the apparent small variation in these two cases.

We have had the privilege of reading, through the courtesy of Dr. Rowe, the manuscript of Rowe, Alcott, and Mortimer on the basal metabolism in pregnancy. We have recalculated their data for the two cases presented by them in detail (Case 13, Series II, and Case 28, Series I) and charted them in Charts 7 and 8, respectively. Their data show that the total heat pro- duction is increased during the last months of pregnancy, but that, if allowance is made for the surface area of the fetus ac- cording to our method, there is little or no change in the rate of heat production of the mother’s tissue during pregnancy. We have also plotted in Chart 8 their curve for total calories each hour (Curve E), representing the average of the twenty-five cases of their Series I. lt is significant that this average curve, although somewhat less steep, nearly parallels the corresponding curve (Curve 0) of their own cases, as well as of the other cases here presented, and this similarity suggests that, if the data were available for recalculation according to our method, no change

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

350 Basal Metabolism in Pregnancy

would be found for the average of the twenty-five cases in the total heat production of a unit mass of the mother’s tissue during pregnancy.

In Table IV we have recalculated and summarized the data on the one patient reported by Hasselbalch and on Case A re- ported by Zuntz, both of which were studied during the last month of pregnancy. Hasselbalch’s control period was obtained 1 month after delivery, while Zuntz used for comparison a few determinations made in the year previous to pregnancy. These cases, as well as the others referred to, confirm the findings in our own case, as when calculated by our method, no alteration

TABLE IV.

Heat Production of Hasselbalch’s Case and of Zuntz’ Case A.

Author.

Hasselbalch. ........... Zuntz, Case A. ........

-

--

-

55.5: 51.6.

2 I 3

-4 4 -- 27.6* 65.1 30.4t 56.2

T- 4 5

+7 27.3 +12 29.9

6 -

_

7

-1 -2

*Determined 1 month after delivery. t Determined in year previous to pregnancy.

is found in the rate of heat production in the mother, of a unit mass of active protoplasmic tissue: The slight variations found in the different cases, as well as in the different periods in each case, are within the limits of experimental error. In this regard the statement of Du Bois is pertinent: “We can rest assured that the actual variations of the basal metabolism are smaller than the variations of the measurements.”

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

I. Sandiford and T. Wheeler 351

CONCLUSIONS.

1. Complete data are given on the respiratory metabolism of a normal woman before, during, and for 6 lunar months after pregnancy. The data show, in agreement with those of other investigators, that there is a definite increase in the total heat production during the latter part of pregnancy, in this case be- ginning with the 8th month and gradually increasing to the 10th lunar month, when the total calories for each hour were 25 per cent greater than before conception.

2. Calculations for this case, as well as for cases from the literature, indicate that the energy production of a unit mass of the mother’s protoplasmic tissue remains unchanged throughout the course of pregnancy, and that such increases in the total heat production as occur are due to the increasing mass of active protoplasmic tissue, consisting in large part of the fetal tissues and in lesser part of maternal structures.

3. There was no increase in heat production duriug lactation. In fact there was a slight decrease, probably because of the less active life. As the mother gradually resumed her usual activities, the metabolism became almost identical with that before pregnancy. There was no demonstrable loss of energy in transforming the mother’s food into milk.

4. There were slight daily irregular variations in the heat pro- duction after the reestablishment of menstruation, but none which can be accredited to its influence.

BIBLIOGRAPHY.

Benedict, F. G., Factors affecting basal metabolism, J. Biol. Chem., 1915, xx, 263.

Benedict, F. G., and Talbot, F., Metabolism and growth from birth to puberty, Carnegie Institution of Washington, Pub. 30.8, 1921.

Blunt, K., and Dye, M., Basal metabolism of normal women, ,I. Biol. Chem., 1921, xlvii, 69.

Boothby, W. M., and Sandiford, I., Basal metabolism, Physiol. Rev., 1924, iv, 69.

Carpenter, T. M., and Murlin, J. R., The energy metabolism of mother and child just before and just after birth, Arch. Int. Med., 1911, vii, 184.

Du Bois, E. F., Basal metabolism in health and disease, Philadelphia, 1924.112.

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

352 Basal Metabolism in Pregnancy

Hasselbalch, K. A., Ein Beitrag zur Respirationsphysiologie der Gravi- ditiit, Skand. Arch. Physiol., 1912, xxvii, 1.

Joslin, E. P., Treatment of diabetes, Philadelphia, 1923, 657. Lusk, G., Science of nutrition, Philadelphia, 1917. Magnus-Levy, Stoffwechsel und Nahrungsbedarf in der Schwangerschaft,

2. Geburtsh. u. Gyndk., 1904, lii, 116. Root, H. F., and Root, H. I$., The basal metabolism during pregnancy and

the puerperium, Arch. Int. Med., 1923, xxxii, 411. Rowe, A. W., Alcott, M. D., and Mortimer, E., The metabolism in preg-

nancy. II. Changes in the basal metabolic rate, J. Biol. Chem., 1924, lix, p. xli; Am. J. Physiol., 1924 (in press).

Sandiford, I., Estimation of the surface area of the fetus, and a graphic comparison of the various surface area formulas, J. Biol. Chem., 1924- 25, lxii, 323.

Sturgis, C. C., Observations on one hundred and ninety-two consecutive days of the basal metabolism, food intake, pulse rate, and body weight in a patient with exophthalmic goiter, Arch. Int. Med., 1923, xxxii, 50.

Talbot, F., Standards of basal metabolism in normal infants and children, Am. J. Dis. Child., 1921, xxi, 519.

Zuntz, L., Respirationscher Stoffwechsel und Athmung wiihrend der Gravi- ditit, Arch. Gynak., 1910, xc, 452.

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from

Irene Sandiford and Theodora WheelerDURING, AND AFTER PREGNANCYTHE BASAL METABOLISM BEFORE,

1924, 62:329-352.J. Biol. Chem. 

  http://www.jbc.org/content/62/2/329.citation

Access the most updated version of this article at

 Alerts:

  When a correction for this article is posted• 

When this article is cited• 

alerts to choose from all of JBC's e-mailClick here

  ml#ref-list-1

http://www.jbc.org/content/62/2/329.citation.full.htaccessed free atThis article cites 0 references, 0 of which can be

by guest on May 21, 2019

http://ww

w.jbc.org/

Dow

nloaded from