|Year : 2005 | Volume
| Issue : 3 | Page : 89-91
A Study of Surrogate Parameters of Birth Weight
YR Kadam, P Somaiya, SV Kakade
Department of P.S.M. Krishna Institute of Medical Sciences, Karad., India
|Date of Web Publication||7-Aug-2009|
Y R Kadam
Department of P.S.M. Krishna Institute of Medical Sciences, Karad.
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Research question : Which anthropometric parameter is correlating highly with birth weight? Can we use this parameter as a screening test for predicting birth weight? What is their cut-off value? Hypothesis: Various anthropometric parameters of newborn correlate each other positively. Objective : To find out the most effective anthropometric parameter in the newborn to assess birth weight so that newborn with LBW can be identified.. Study design: Hospital based cross-sectional study. Participants : Newborn babies born in KIMS, Karad. Results : Relatively highest correlation was observed between birth weight & thigh circumfirence (T.C.) (r = 0.8637) & next with chest circumfirence (C.C.). (r = 0.8247) Cut-off values of T.C. & C.C. had better sensitivity, specificity & predictive value for identifying LBW babies. Conclusion : T.C. is the best effective parameter to predict birth weight. Next to it is C.C.
Keywords: Birth Weight, Low Birth Weight, Anthropometric Parameters
|How to cite this article:|
Kadam Y R, Somaiya P, Kakade S V. A Study of Surrogate Parameters of Birth Weight. Indian J Community Med 2005;30:89-91
| Introduction|| |
One in three babies in India are born with moderate to severe malnutrition with birth weight of 2500 gm or below. Babies having low birth weight are more susceptible to infection and they do not grow to their full potential of physical and mental abilities and start their life at disadvantage leading to high infant morbidity & mortality. Hence it is imperative to identify the newborns with low birth weight and to offer them adequate and needed care instantly for their survival. However in developing countries like India 70-90% deliveries occur at home where weighing facility does not exist or due to certain logistic problems  and as a result babies with low birth weight could not be identified and these babies are deprived of much needed adquate and immediate care.
The logistic problems such as non availability of weighing machine is also big hurdle in recording the birth weight, even though the deliveries are conducted by properly trained health personal. As a result in many cases LBW babies remain undetected, which also reflects adversely upon the 'high risk' aproach to ensure better child survival.
| Material & Methods|| |
This study was carried out in the Krishna Hospital & Medical Research Center (KH&MRC) Karad, for a period of six month. This hospital is attached to Krishna Medical College.
All deliveries that took place during this period were included in the study. Total 293 live births took place. Out of which 14 new borns were not included, since the worker could not record their birth weight and other anthropometric measurements during first 48 hours after their birth as per WHO recommendation due to certain unavoidable reasons  . Thus 279 newborns were included in the study. Equipments used during the study were of flexible, non-stretchable measuring tapes a spring dial weighing machine, a vertical measuring rod and a pediatric weighing machine capacity of measuring upto 0.1 cm, 50 gm 0.1 cm and 50 gms respectively which include general demographic information obstetric history and anthropometric of newborn.
Anthropometric measurements in respect to newborns were
- Mid arm circumference (MAC)
- Maximum thigh circumference (TC)
- Calf circumference (CFC)
- Chest circumference (CC)
- Head circumference (HC) and
- Birth weigh (BW)
The methodology employed in respect of these anthropometric measurements was as per a standardized recommended procedures ,,, .
Data was fed and analysed by computer with the help of statistical package 'STATPAL'.
| Results|| |
It was observed in the study that the difference in the mean birth weight between male and female babies is not significant (t-1.94, p>0.05). Further, no significant difference was observed between the mean birth weight of male and female babies with weight less than 2500 gms (t=1.25, p>0.1) and less than 2000gms (t=0.66, p>0.1).
[Table 1] shows than there is no significant difference in anthropometric parameters of all male & female newborns, male & female newborns with weight <2000 gms & male & female newborns weight <2500 gms.
It was observed that birth weight is significantly correlated with all studied anthropometric parameters (P<0.001). However the thigh circumference has a relatively higher correlation value than the other parameters. After TC, the next anthropometric parameter with a relatively higher correlation with birth weight was found to be the CC. [Table 2]
[Table 3] shows simple regression equation for estimating birth weight (y) for babies with birth weight less than 2500gms, in relation to various studied anthropometric variables with R 2 ,the predictive value, R 2 of birth weight is higher in relation to TC followed by CC.
[Table 4] shows validity parameters of the cut off values of all studied anthropometric parameters for weight < 2500gms. The highest sensitivity and predictive -ve value is observed for TC followed by CC. Simpler findings was observed for various parameter when wt < 2000 gm.
[Table 5] shows correlation coefficient between birth weight and other anthropometric parameters obtained by various researchers. Other studies have also mentioned TC as the best surrogate parameter in estimating birth weight ,, .
| Discussion|| |
The prime concern of the present study was to identify the best suitable surrogate parameter, proxy, to birth weight, which when used by the health personnel in domiciliary outreach will detect the maximum number of at risk infants for providing them with timely and needed intervention strategy.
Scrutiny of collected data reveals that none of the studied parameters have shown the highest value of all validity parameters; thought positive correlation between all studied parameters and birth weight was observed. Hence the suggestion of best surrogate parameter has been done by choosing the combination of the validity parameters.
At weight <2500 gm, <2000 gm, TC is suggested as the best surrogate parameter to predict baby as LBW. It shows the highest sensitivity 94.95% and negative predictive value 95.8%. The next best surrogate parameter is CC.
In this situation increase in the false positive diagnosis is inevitable. But considering the problem of LBW a) the neonate with false negative result generally cause no concern either for parents or for health personal. But in reality LBW baby is at greater risk of high morbidity and high mortality. b) Whereas by false positive diagnosis, healthy neonates will be subjected to further screening at nearby referral center causing some inconvenience, discomfort & expenses to the family. Thus increase in the number of false positive will enhance the burden at the secondary screening center, which is mainly in terms of efforts of weighing the referred neonate. Hence it is sincerely felt that the penalty of false negative diagnosis is much more painful than the increased burden of weighing the neonates and declaring them as a baby having a normal weight. This opportunity may be exploited at the referral center for educating mother or father on immunization regarding feeding of baby, nutrition, family planning, importance of personal hygiene etc.
Thus, it is evident from anlysis of our data that TC is the best suitable and simple surrogate parameter that could be used in the domiciliary outreach when it is impossible to record weight of baby at birth. For health personnel who are working in the community can use color coded tapes indicting weight <2000 gms, between 2000 gms and 2500 gms and above 2500 gms. With this technique, measurement errors are likely to be less as measurements of thigh is taken at it's maximum circumference, since at that section, larger amount of soft tissue is present.
In conclusion, TC is the best suitable parameter for predicting LBW (<2500 gms & <2000 gms) neonate while CC is the next best parameter. The use of such indicator would help to identify neonates requiring intervention to prevent deaths, diseases and disability. This will be a viable example of practical and cost effective health care strategy.
| Conclusion|| |
On evaluation of the validity of these cut off values if was observed that TC of <=15.29 cm. and <=12.97 cm. and CC of <=30.16 cm and <=27.3 cm. had the better sensitivity, specificity & predictive value for identifying infants weighing <=2500 gms. & <=2000gms. respectively.
| Recommendations|| |
TC and CC can be used as a surrogate parameter of birth weight.
Tapes with different colored risk zones could be devised & tested for reliability so that they can be used in community.
| References|| |
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]
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