AUST.AND N.Z.
114
JOURNAL OF OB%ETRICS AND
breech or vertex-transverse presentations because of the possibility of IVBE being required to effect delivery. It should be noted that the 2 second twins with significant neurological impairment were born at 29 and 30 weeks’ gestation respectively (table 5). This paper has not addressed itself to the numerically greater but quite different problem of breech extraction which is required for the method of delivery of more than 10% of second twins (table 1). Although IVBE is required in only about 1 in I5 second twins, the obstetricians attitudes and willingness to embark on this procedure will determine whether delivery will be effected by the abdominal o r vaginal routes. Reluctance to perform IVBE may result in elective Caesarean section being performed in patients with multiple pregnancy.
Acknowledgements We wish to thank Dr. R. L. Hudson and officers of the National Acoustic Laboratories for the visual and
Aust
GYNAECOt-WiY
audiological assessments of the children. Mrs. J. Walstab performed the statistical analyses. This study was supported by the Mercy Maternity Hospital Research Foundation.
References 1. Faroogui MO, Grossman JH, Shannon RA. A review of twin 2.
3. 4. 5.
7. 6.
8.
pregnancy and perinatal mortality. Obster Gynecol Surv 1973: 2 8 144-153. Cetrulo CL, Ingardia CJ, Sbarra AJ. Management of multiple gestation. Clin Obstet Gynecol 1980; 2 3 533-548. Ho SK, Wu PYK. Perinatal factors and neonatal morbidity in twin pregnancy. Am 3 Obstet Gynecot 1975; 122: 979-987. Ware HH. The second twin. Am J Obsiet Gynecol 1971; 1 1 0 865-869. Acker D, Lieberman M, Holbrock H, James 0.Phillipe M, Edelin KC. Delivery of the second twin. Obstet Gynecol 1982; 5 9 710-711. Bayley N. Manual for the Bayley Scales of infant Debetopment, New York: the Physiological Corporation, 1969. McCarthy D. McCarthy Scale of Childrens Abilities, New York: the Psychological Corporation, 1970. lllingworth RS. The Development of the Infant and Young Child: normal and abnormal, New York: Churchill titingrrone, 1980: ~31.
NZ J Obstei Cynaecol 1991: 31: 2 114
The Influence of PaternaI Height and Weight on ~ i ~ ~ ~ w ~ J. Morrison*, G. M. Williams, J. M. Najman and M. J. Andersen Departments of Obsteirics and Gynaecology, Social and Preventive Medicine, and Anthropology and Sociology, University of Queenstand, Brisbane
Summary: Analysis of 5,989 couples, for whom fathers’ and mothers’ heights and weights were recorded, showed that paternal height had a significant influence (p { 0.0007) on birth-weight while paternal body mass index (Quetelets Index) had no significant effect (p)O.O5). Depending upon mother’s height, the average effect of father’s height (ranging from 165 cm to 184 cm) on birth-weight was up to 152 g. with a greater effect where the mother was taller (up to 235 g) and a lesser effect where the mother was shorter (confirming the effect of maternal constraint). The significance of these findings lies more with the need to consider this effect as an important variable in statistical analysis involving birth-weight than in its immediate obstetrical implications.
A number of factors have been shown to influence human fetal birth-weight. These have been extensively reviewed by Hytten and h i t c h (1) and Hytten and Chamberlain (2) who have emphasized the prominent effect of maternal factors, such as maternal height and weight, weight increase in pregnancy, and variables such ‘Present address: Chairman, Department OB/GYN. Faculty of Medicine and Health Sciences, U.A.E. University, PO.Box 17666, AL-AIN, United Arab Emirates.
as age, socioeconomic status, parity and sex of the infant. They concluded on the basis of their review, which included some of the classical veterinary experiments (3-5) and family analysis (6-9) that ‘the father has no influence on intrauterine growth: We also have previously examined factors contributing to fetal birthweight in our hospital population (10) and confirmed most of the above claims but were not able to address the issue of paternal effects as the data were not available. This current study was designed to determine uhether or not paternal factors influence birth-wight.
J. MORRISON ET AL
No of couDles
115
Birth weight fkg)
a
3.8
2
3.6 500
-I
3.5 400
300
-I
3.2 3.1
200
3 160
165
170
175
180
185
190
Father’s heiaht (cm)
100
Mother’s height (crn) 0
Father’s height (crn)
-8- (154
+ 155-159
-e- 165-169
--)t
height (cm)
> 169
*
160-164
- Mean (162.7 crn)
Means platted at mean for height group
Figure I. Association between parental heights for 5,989 couples.
Figure 2. Association between paternal height and birth-weight.
The original sample consisted of 8,556 patients admitted to a study designed to examine ‘The Effect of Social, Psychological and Obstetric Factors on Reproductive Outcome’ of which the demographic and social characteristics have been documented by Keeping et a1 (11) and Morrison et a1 (12). The subset of the original cohort used for analysis in this study were those who had known heights and weights for both partners, had no significant medical disease, booked prior to 20 weeks’ gestation and delivered the fetus after the 36th completed week of pregnancy. Stillbirths, major fetal abnormalities and chromosomal abnormalities were also excluded. leaving a residual group of 5,989couples for analysis. METHODS Analysis of birth-weight (g) upon gestation (in completed weeks from the 36th week) and parents’ height and body mass indices (BMI) using Quetelets Index [weight (kg) divided by height’ (m’)] was performed
using the statistical package SAS (Version 5). A quadratic term was included for gestation in order to account for the change in fetal growth mte in later stages of pregnancy. For this analysis father’s height, mother’s height and mother’s BMI were categorized in 7 divisions, and father’s BMI in 6 divisions: Father’s height (cm): ( 165; 165-169; 170-174; 175-179;
Table 1. Analysis of mrianee of birth-weieht (adjusted for entation) Factor Height Mother Father Interaction
b d y Mass index (queteletsf Mother
Father Interaction Variance explained: Residual S.D.
df 6 6 36
F value
Significance
14.25 3.88 1.23
p(O.OOO1 p (0.0007 0)0.05
6 33.7 5 1.64 30 0.68 8.5% 431.3 5799 df
p(O.OOO1 p)0.05 p)0.05
180-184; 185-189;
> 190.
Mother’s height (cm): ( 1.50; 150-154; 155-159; 160-164; Father’s BMI: Mother’s BMI:
165-169; 170-174; > 175. (20; 20-21.9; 22-23.9; 24.25.9; 26-27.9; >28. (18; 18-19.9; 20-21.9; 22-23.9; 24-25.9; 26-27.9; > 28.
RESULTS Analysis confirmed that ‘like tends to marry like‘ with a correlation coefficient of 0.16 between parents’ heights and 0.15 between parents’ body mass indices (BMI). A graphic representation of the correlation between parent’s heights is shown in figure 1. Table 1 shows that paternal height had a significant effect (p ( 0.0007 on birth-weight although paternal BMI had no significant effect (p)0.005). It also confirmed the well established effects of maternal height and BMI on the fetal weight at delivery. The effects of paternal height and BMI in relation to maternal height and BMI are graphicaily represented in figures 2 and 3 respectively with the original categories reduced to 3 for the father and 5 for the mother for ease of visual interpretation.
AUST. AND N.Z. JOURNALOF OBSCETRIC’S AND GYNAECOLOC~Y
116
The overall effect of paternal height on birth-weight in our population was of the same order as smoking (up to approximately 150 g ) (unpublished data) and considerably more than socioeconomic status (approximately 50g) (12). While this effect on birth-weight will probably have little impact on the management of labour or in obstetrical practice, it should be considered an important variable in any statistical analysis which involves birth-weight. Q
3.3
n
3.2 3. I
,
3
References
I
1. Hytten and Leitch Editors. The Physiology of Human Pregnancy. Blackwell Scientific Publications. Oxford 1964. 2. Hytten and Chamberlain Editors. Clinical Physiology in Obstetrics. Blackwell Scientific Publications, Oxford 1980: 202. 3. Walton A, Hammond J. The Maternal Effects on Growth and
Mother’s BMI -8- (20
24-25.9
+ 20-21.9
++ 2 26
Acknowledgement We wish to acknowledge the funding provided by the National Health and Medicai Research Council of Australia for this study.
+ 22-23.9
- Mean
(23.6)
Means plotted at mean for BMI group Figure 3. Association between parental BMI and birth-weight.
DISCUSSION The results clearly demonstrated that paternal height significantly affected birth-weight. The magnitude of this effect was less than either maternal height or maternal weight and was approximately a quarter of the former with an average effect over the range of father’s height (from 165 cm - 184 cm) of 152 g. Figure 2 also confirms the presence of ‘maternal constraint’ with the babies of shorter mothers showing a lesser increase in birth-weight of up to 130 g, while babies of taller mothers showed a much greater increase in birth-weight of up to 235 g (in relation to the height of the father).
Conformation in Shire Horse-Shetland Pony Crosses. Proc Roy Soc B 1938; 125: 311. 4. Joubert DM, Hammond J. Maternal Effects on Birth Weight South Devon and Dexter Cattle Crosses. Nature (London) 1954: 174: 647. 5. Starke JS, Smith JB, Joubert DM. The Birth Weight of Iambs. Union of S. Africa, Dept. of Agriculture, Science Bull. IY5X: No. 382. 6. Donald HP. Sources of Variations in Human Birth Wcightc. P r w Roy Soc (Edinb) 1938-1939; 5 9 91. 7. Morton NE. The lnheritanceof Human Birth Weight. A m Hum Genet 1955: 2 0 125. 8. Robson E R The Genetics of Human Birth Weight. Hcrcdiiy 1953; I: 149. 9. Robson EB. Birth Weight in Cousins. Am ffuman (icnet 1954-1955; 19: 262. 10. Keeping JD. Chang J. Morrison 3. f:\ler f f . Hiah Weight: Analysis of Variance and the Linear Additive Model. Nr J Ohstct Gynaecol 1979; 8 6 437-442. 11. Keeping JD. Najman JM. Morrison J. Wkstcrn JS. Anderxn MJ. Williams GM. A Prospective Longitudinal Study of Social.
Psychological and Obstetrical Factors in Pregnancy: Response Rates and Demographic Characteristics of the 8556 Respondents. Br J Obstet Gynaecol 1989; % 289-297. 12. Morrison J, Najman JM. Williams GM. Keeping JD. Andersen MJ. Socio-economic Status and Pregnancy Outcome: An Australian Study. Br J Obstet Gynaecol 1989: 96:298-307.
114
JOURNAL OF OB%ETRICS AND
breech or vertex-transverse presentations because of the possibility of IVBE being required to effect delivery. It should be noted that the 2 second twins with significant neurological impairment were born at 29 and 30 weeks’ gestation respectively (table 5). This paper has not addressed itself to the numerically greater but quite different problem of breech extraction which is required for the method of delivery of more than 10% of second twins (table 1). Although IVBE is required in only about 1 in I5 second twins, the obstetricians attitudes and willingness to embark on this procedure will determine whether delivery will be effected by the abdominal o r vaginal routes. Reluctance to perform IVBE may result in elective Caesarean section being performed in patients with multiple pregnancy.
Acknowledgements We wish to thank Dr. R. L. Hudson and officers of the National Acoustic Laboratories for the visual and
Aust
GYNAECOt-WiY
audiological assessments of the children. Mrs. J. Walstab performed the statistical analyses. This study was supported by the Mercy Maternity Hospital Research Foundation.
References 1. Faroogui MO, Grossman JH, Shannon RA. A review of twin 2.
3. 4. 5.
7. 6.
8.
pregnancy and perinatal mortality. Obster Gynecol Surv 1973: 2 8 144-153. Cetrulo CL, Ingardia CJ, Sbarra AJ. Management of multiple gestation. Clin Obstet Gynecol 1980; 2 3 533-548. Ho SK, Wu PYK. Perinatal factors and neonatal morbidity in twin pregnancy. Am 3 Obstet Gynecot 1975; 122: 979-987. Ware HH. The second twin. Am J Obsiet Gynecol 1971; 1 1 0 865-869. Acker D, Lieberman M, Holbrock H, James 0.Phillipe M, Edelin KC. Delivery of the second twin. Obstet Gynecol 1982; 5 9 710-711. Bayley N. Manual for the Bayley Scales of infant Debetopment, New York: the Physiological Corporation, 1969. McCarthy D. McCarthy Scale of Childrens Abilities, New York: the Psychological Corporation, 1970. lllingworth RS. The Development of the Infant and Young Child: normal and abnormal, New York: Churchill titingrrone, 1980: ~31.
NZ J Obstei Cynaecol 1991: 31: 2 114
The Influence of PaternaI Height and Weight on ~ i ~ ~ ~ w ~ J. Morrison*, G. M. Williams, J. M. Najman and M. J. Andersen Departments of Obsteirics and Gynaecology, Social and Preventive Medicine, and Anthropology and Sociology, University of Queenstand, Brisbane
Summary: Analysis of 5,989 couples, for whom fathers’ and mothers’ heights and weights were recorded, showed that paternal height had a significant influence (p { 0.0007) on birth-weight while paternal body mass index (Quetelets Index) had no significant effect (p)O.O5). Depending upon mother’s height, the average effect of father’s height (ranging from 165 cm to 184 cm) on birth-weight was up to 152 g. with a greater effect where the mother was taller (up to 235 g) and a lesser effect where the mother was shorter (confirming the effect of maternal constraint). The significance of these findings lies more with the need to consider this effect as an important variable in statistical analysis involving birth-weight than in its immediate obstetrical implications.
A number of factors have been shown to influence human fetal birth-weight. These have been extensively reviewed by Hytten and h i t c h (1) and Hytten and Chamberlain (2) who have emphasized the prominent effect of maternal factors, such as maternal height and weight, weight increase in pregnancy, and variables such ‘Present address: Chairman, Department OB/GYN. Faculty of Medicine and Health Sciences, U.A.E. University, PO.Box 17666, AL-AIN, United Arab Emirates.
as age, socioeconomic status, parity and sex of the infant. They concluded on the basis of their review, which included some of the classical veterinary experiments (3-5) and family analysis (6-9) that ‘the father has no influence on intrauterine growth: We also have previously examined factors contributing to fetal birthweight in our hospital population (10) and confirmed most of the above claims but were not able to address the issue of paternal effects as the data were not available. This current study was designed to determine uhether or not paternal factors influence birth-wight.
J. MORRISON ET AL
No of couDles
115
Birth weight fkg)
a
3.8
2
3.6 500
-I
3.5 400
300
-I
3.2 3.1
200
3 160
165
170
175
180
185
190
Father’s heiaht (cm)
100
Mother’s height (crn) 0
Father’s height (crn)
-8- (154
+ 155-159
-e- 165-169
--)t
height (cm)
> 169
*
160-164
- Mean (162.7 crn)
Means platted at mean for height group
Figure I. Association between parental heights for 5,989 couples.
Figure 2. Association between paternal height and birth-weight.
The original sample consisted of 8,556 patients admitted to a study designed to examine ‘The Effect of Social, Psychological and Obstetric Factors on Reproductive Outcome’ of which the demographic and social characteristics have been documented by Keeping et a1 (11) and Morrison et a1 (12). The subset of the original cohort used for analysis in this study were those who had known heights and weights for both partners, had no significant medical disease, booked prior to 20 weeks’ gestation and delivered the fetus after the 36th completed week of pregnancy. Stillbirths, major fetal abnormalities and chromosomal abnormalities were also excluded. leaving a residual group of 5,989couples for analysis. METHODS Analysis of birth-weight (g) upon gestation (in completed weeks from the 36th week) and parents’ height and body mass indices (BMI) using Quetelets Index [weight (kg) divided by height’ (m’)] was performed
using the statistical package SAS (Version 5). A quadratic term was included for gestation in order to account for the change in fetal growth mte in later stages of pregnancy. For this analysis father’s height, mother’s height and mother’s BMI were categorized in 7 divisions, and father’s BMI in 6 divisions: Father’s height (cm): ( 165; 165-169; 170-174; 175-179;
Table 1. Analysis of mrianee of birth-weieht (adjusted for entation) Factor Height Mother Father Interaction
b d y Mass index (queteletsf Mother
Father Interaction Variance explained: Residual S.D.
df 6 6 36
F value
Significance
14.25 3.88 1.23
p(O.OOO1 p (0.0007 0)0.05
6 33.7 5 1.64 30 0.68 8.5% 431.3 5799 df
p(O.OOO1 p)0.05 p)0.05
180-184; 185-189;
> 190.
Mother’s height (cm): ( 1.50; 150-154; 155-159; 160-164; Father’s BMI: Mother’s BMI:
165-169; 170-174; > 175. (20; 20-21.9; 22-23.9; 24.25.9; 26-27.9; >28. (18; 18-19.9; 20-21.9; 22-23.9; 24-25.9; 26-27.9; > 28.
RESULTS Analysis confirmed that ‘like tends to marry like‘ with a correlation coefficient of 0.16 between parents’ heights and 0.15 between parents’ body mass indices (BMI). A graphic representation of the correlation between parent’s heights is shown in figure 1. Table 1 shows that paternal height had a significant effect (p ( 0.0007 on birth-weight although paternal BMI had no significant effect (p)0.005). It also confirmed the well established effects of maternal height and BMI on the fetal weight at delivery. The effects of paternal height and BMI in relation to maternal height and BMI are graphicaily represented in figures 2 and 3 respectively with the original categories reduced to 3 for the father and 5 for the mother for ease of visual interpretation.
AUST. AND N.Z. JOURNALOF OBSCETRIC’S AND GYNAECOLOC~Y
116
The overall effect of paternal height on birth-weight in our population was of the same order as smoking (up to approximately 150 g ) (unpublished data) and considerably more than socioeconomic status (approximately 50g) (12). While this effect on birth-weight will probably have little impact on the management of labour or in obstetrical practice, it should be considered an important variable in any statistical analysis which involves birth-weight. Q
3.3
n
3.2 3. I
,
3
References
I
1. Hytten and Leitch Editors. The Physiology of Human Pregnancy. Blackwell Scientific Publications. Oxford 1964. 2. Hytten and Chamberlain Editors. Clinical Physiology in Obstetrics. Blackwell Scientific Publications, Oxford 1980: 202. 3. Walton A, Hammond J. The Maternal Effects on Growth and
Mother’s BMI -8- (20
24-25.9
+ 20-21.9
++ 2 26
Acknowledgement We wish to acknowledge the funding provided by the National Health and Medicai Research Council of Australia for this study.
+ 22-23.9
- Mean
(23.6)
Means plotted at mean for BMI group Figure 3. Association between parental BMI and birth-weight.
DISCUSSION The results clearly demonstrated that paternal height significantly affected birth-weight. The magnitude of this effect was less than either maternal height or maternal weight and was approximately a quarter of the former with an average effect over the range of father’s height (from 165 cm - 184 cm) of 152 g. Figure 2 also confirms the presence of ‘maternal constraint’ with the babies of shorter mothers showing a lesser increase in birth-weight of up to 130 g, while babies of taller mothers showed a much greater increase in birth-weight of up to 235 g (in relation to the height of the father).
Conformation in Shire Horse-Shetland Pony Crosses. Proc Roy Soc B 1938; 125: 311. 4. Joubert DM, Hammond J. Maternal Effects on Birth Weight South Devon and Dexter Cattle Crosses. Nature (London) 1954: 174: 647. 5. Starke JS, Smith JB, Joubert DM. The Birth Weight of Iambs. Union of S. Africa, Dept. of Agriculture, Science Bull. IY5X: No. 382. 6. Donald HP. Sources of Variations in Human Birth Wcightc. P r w Roy Soc (Edinb) 1938-1939; 5 9 91. 7. Morton NE. The lnheritanceof Human Birth Weight. A m Hum Genet 1955: 2 0 125. 8. Robson E R The Genetics of Human Birth Weight. Hcrcdiiy 1953; I: 149. 9. Robson EB. Birth Weight in Cousins. Am ffuman (icnet 1954-1955; 19: 262. 10. Keeping JD. Chang J. Morrison 3. f:\ler f f . Hiah Weight: Analysis of Variance and the Linear Additive Model. Nr J Ohstct Gynaecol 1979; 8 6 437-442. 11. Keeping JD. Najman JM. Morrison J. Wkstcrn JS. Anderxn MJ. Williams GM. A Prospective Longitudinal Study of Social.
Psychological and Obstetrical Factors in Pregnancy: Response Rates and Demographic Characteristics of the 8556 Respondents. Br J Obstet Gynaecol 1989; % 289-297. 12. Morrison J, Najman JM. Williams GM. Keeping JD. Andersen MJ. Socio-economic Status and Pregnancy Outcome: An Australian Study. Br J Obstet Gynaecol 1989: 96:298-307.
