Indmedica Home | About Indmedica | Medical Jobs | Advertise On Indmedica
Search Indmedica Web
Indmedica - India's premier medical portal

Indian Journal of Community Medicine

A Study of Factors Affecting LBW

Author(s): Kiran Anand, B.S. Garg

Vol. 25, No. 2 (2000-04 - 2000-06)

Department of Community Medicine, Mahatma Gandhi Institute of Medical Sciences, Sevagram, Distt. Wardha 442102, Maharastra


Research question: What are the factors responsible for low birth weight babies?

Objective: To find out the socio-economic and maternal factors affecting LBW babies.

Study-design: Longitudinal study design for mothers booked in the MCH centre of the department and cross-sectional design for unbooked mothers at the Kasturba Hospital.

Participants: Antenatal mothers coming for regular check-ups at the MCH centre of the department and those admitted in the obstetric wards of the Kasturba hospital.

Sample size: 256 pregnant mothers (booked and unbooked).

Study variables: Socio-economic and maternal characteristics.

Statistical analysis: Chi-square test, univariate odds ratio with 95% confidence interval.

Results: The overall mean birth weight of all the newborns was 2.53±0.424 kg. The factors which were significant for LBW were antenatal care during pregnancy, maternal education, occupation, per capita income, parity, bad obstetric history, pre delivery weight and haemoglobin concentration. However, maternal age and weight gain during pregnancy were not found to be statistically significant factors.

Keywords: Low birth weight, Antenatal care, Mean birth weight, Pregnancy.


Birth weight is a single most important criteria for determining the neonatal and infant survival. WHO defines LBW as "Birth weight less than 2500 gm"1. Globally, it is estimated that 25 million LBW infants were born in 1990 constituting 18% of all the live births. Of these 90% belonged to the developing countries2. In India, 30-35% babies are LBW and more than half of these LBW infants are full term babies3. This study was, therefore, designed to study the effect of various socio-economic and maternal factors on the birth weight of a newborn.

Material and Methods:

The subjects were selected from the MCH centre of department of Community Medicine, Sevagram and obstetric wards of Kasturba hospital. For mothers who were booked at our MCH centre, a longitudinal study design was employed and cross-sectional study was done on mothers who came directly for their delivery at the institution. It is noted from the literature that the proportion of LBW babies constituted to the extent of nearly 30% in the community. Based on this, in order to study effect of various factors, the required sample size for study was estimated at the probability level of 5% with a permissible error of 20%.

All pregnant mothers (128) coming to the MCH clinic were booked and called regularly for antenatal care. A complete per abdomen examination, clinical profile along with her height, weight, weight gain during pregnancy, B.P., blood and urine examination were undertaken. Dietary advise was given along with iron and folic acid tablets as well as tetanus toxoid injections as per the CSSM schedule.

Besides these, 128 pregnant mothers who came directly for their delivery and never visited any medical centre for antenatal care were selected at random from the obstetric wards of the hospital. Their check-up and investigations were done prior to their delivery. Each newborn's weight was taken immediately after birth alongwith the assessment of their general physical condition. The babies weighing less than were labelled as LBW babies.

Statistical analysis:

Initially the data was stipulated according to the various socio-economic and maternal factors included in the study. In order to test for association between two variables, a chi-square test of significance was applied. Further, univariate odds ratios alongwith their 95% confidence interval for various levels of different factors were computed.


The mean birth weight of all the babies was 2.58_+0.42 kg. A significantly higher number of LBW babies were seen in unbooked mothers. Out of all the booked mothers, outcome was better in mothers who got registered in the 1st trimester. Similarly, the birth weight of babies seemed to be influenced significantly by the number of antenatal visits made by the mother (p<0.001). Unbooked mothershad 8 times higher risk of having a LBW baby in comparison to those who had 5 or more visits as shown in Table I.

Table I: Antenatal care and birth weight of the new borns.

Factors Levels of factor No. of newborns LBW No.(%) OR 95%CI Significance test
Registration of mothers Booked 128 30   1.0
Unbooked 128 64 (50.0) 3.27 1.85-5.75 p<0.001
Time of registration* Ist trimester 24 5 (20.8) 1.0
2nd trimester 55 12 (21.8) 1.16 0.29-4.04
3rd trimester 49 13 (26.5) 1.37 0.375-5.23 p<0.05
No. of antenatal visits Unbooked 128 64 (50.0) 8.2 2.86-25.33
<2 9 4 (44.4) 2.52 0.47-13.32
2-4 73 21 (28.8) 3.3 1.06-11.04
≥5 46 5 (10.9) 1.0 p<0.001

*Out of 128

Table II summarises the effect of socio-economic factors on birth weight of the new born. Maternal education had a significant association with the birth weight of the newborn. 67.8% of LBW babies belonged to mothers who were labourer by occupation. On comparing house-wives with labourers, the difference was found to be highly significant (p<0.001). However, the association between service class and housewives was not significant which could be due to the sample size being less in service class group. Mothers who belonged to low income group had more number of LBW babies in comparison to higher income group. Maximum number of LBW babies (81.5%) were born to mothers whose per capita income (per month) was less than Rs. 150(OR=30.8).

Table II: Relationship of socio-economic factors with LBW.

Factors Levels of factor No. of newborns LBW No.(%) OR 95%CI Significance test
Maternal education Illiterate 68 45 (66.2) 17.04 6.6-44.57
Upto middle 111 36 (32.4) 2.36 1.1-5.16
Intermediate and above 77 13 (16.8) 1.0 p<0.001
Maternal occupation House-wife 163 36 (22.0) 7.33 3.91-13.83
Labourer 84 57 (67.8) 0.43 0.01-3.62
Service class 9 1 (11.1) 1.0 p<0.001
Percapita income <150 65 53 (81.5) 30.8 9.44-102.38
Per month in Rs. 150-299 81 22 (27.2) 2.55 0.88-7.74
300-499 63 13 (20.6) 1.78 0.56-5.81
≥500 47 6 (12.8) 1.0 p<0.001

Table III summarizes the relationship of maternal factors with LBW. More number of LBW babies were born to mothers who were less than 20 years of age. The relationship between maternal age and LBW was not found to be statistically significant (p>0.05). Maximum number of mothers were primipara (41%) with more number of LBW babies. The association was found to be highly significant. Mother who had a bad obstetric history showed poor outcome in their present pregnancy also. Independently when abortions, still births and previous LBWs were compared with mothers without BOH, the relationship was found to be highly significant. A high number of LBW newborns (45%) were seen in mothers whose pre delivery weight was less than 45 kg (OR=7.1). Out of all the booked mother, maximum number of LBW babies were born to mothers with weight gain of 4kg or less. When compared with mothers whose weight gain was more than 10 kg the risk of having an LBW baby was 4 times higher. A statistically significant relationship was found between the haemoglobin concentration and birth weight of the newborns.

Table III : Relationship of maternal factors with LBW.

Factors Levels of factor No. of Newborns LBW No.(%) OR 95%CI Significance test
Maternal age <20 53 22 (41.5) 1.36 0.66-2.82
21-24 108 37 (34.3) 1.0
25-26 75 28 (37.3) 1.14 0.59-2.0
≥29 20 7 (35.0) 1.03 0.34-3.09 p>0.05
Parity 1 106 53 (50.0) 3.05 1.58-5.91
2 89 22 (24.7) 1.0
3 46 16 (34.8) 1.6 0.7-3.8
≤4 15 3 (20.0) 0.76 .003-3.32 p<0.001
BOH Abortion 32 18 (56.2) 4.22 1.78-10.1 p<0.001
Still birth 18 9 (50.0) 3.29 1.09-9.92 p<0.05
Previous LBW 31 18 (58.0) 4.55 1.89-11.04 p<0.001
Perinatal death 12 9 (75.0) 9.86 2.27-35.06 p<0.001
Others 13 5 (38.5) 2.05 0.54-7.54
No BOH 150 35 (23.3) 1.0
Maternal Predelivery weight in kg <45 80 36 (45.0) 7.1 1.83-24.38
45-50 98 39 (39.8) 5.7 1.5-20.0
51-55 49 16 (32.6) 4.2 0.99-17.85
≤56 29 3 (10.3) 1.0 p<0.05
Maternal weight gain in kg* ≤4 9 4 (44.4) 4 0.22-516.39
5-7 88 16 (18.2) 1.11 0.11-1.75
8-10 25 9 (36.0) 2.8 0.24-336.91
>10 6 1 (16.7) 1.0 p>0.5
Haemoglobin conc. in gm% ≥7 13 9 (69.2) 14.1 2.34-99.25
7.1-8 63 49 (77.8) 21.88 5.54-90.01
8.1-9 74 22 (29.7) 2.64 0.75-10.19
9.1-10 77 10 (13.0) 0.93 0.24-3.92
≤10 29 4 (13.8) 1.0 p<0.001

*Out of 128

However, association between maternal diseases like hypertension with LBW could not be drawn as only 3 mothers were found to be suffering from hypertension.


LBW is associated with high neonatal mortality and, therefore, it is important to reduce the incidence of LBW.

A higher number of LBW babies were born to mothers who were unbooked and out of the booked those with less number of antenatal visits (Table I). Similar findings have been observed earlier4-8. Out of all the booked mothers, lowest number of LBW infants were observed in those booked in the Ist trimester9,10 and those coming for more than 5 antenatal visits11-13. This indicates the role of antenatal care in preventing LBW babies.

Our finding that more number of LBW babies were observed in mothers who were illiterate or less educated was in conformity with earlier reports13-16. This may be explained by the increased awareness of educated women regarding available health services leading to change in health seeking behaviour and intake of adequate nutrition.

Maximum number of LBW babies were born to mothers who were labourer by occupation as documented in earlier studies 14,17-21. Although in our study only one LBW baby was born to the service class mothers as compared to the higher number in the house-wives this could be due to the rural set up of the hospital. The number of LBW babies decreased with increase in the per capita income of the family. These findings are in accordance with other studies5,13-22.

More number of LBW babies were born to mothers whose age was <20 years and those born to primipara as also reported earlier 4,8. This could be attributed to the mother being unprepared, unaware or inexperienced. We observed more number of LBW babies in mothers with a previous history of perinatal death, previous LBW baby and abortions and this was in conformity with other studies12,23,25. Mothers whose pre delivery weight was <45 kg had maximum number of LBW babies as also suggested by others4,8,15,26. Similarly, as in our study, a large number of reports have confirmed the significant relationship between maternal weight gain during pregnancy and the neonatal outcome27. It has long been recognised that anaemia is a major nutritional problem in poor segments of the population. As seen in the study, there is a significant relationship between mother's haemoglobin concentration and the birth weight of the newborn also supported by many studies 27-29.


We are grateful to Dr. N.S. Murthy, Dy. Director, Epidemiology and Biostatistics, ICPO and Dr. D.K. Taneja, Professor Department of PSM, MAMC for their help extended to us.


  1. Kramer MS: Determinants of LBW, Methodological assessment and meta analysis. Who Bull 1987; 65(5): 663-737.
  2. Belsey MA: Global overview of new born health. Int. Child Health 1993; 4(1): 13-32.
  3. Park JE, Park K: Text book of Preventive and Social medicine 1991; 13: 307.
  4. Theodre K, Abel K, Kumar S: Epidemiological correlates of LBW in rural Tamil Nadu. Ind J Paed 1990; 59: 299-304.
  5. Makhija K, Murthy GVS, Kapoor SK, Lobo J: Socio-biological determinants of birth weight. Ind J Paed 1989; 56: 639-43.
  6. Bachani D, Agarwal DK, Mathur HN: Maternal factors influencing birth weight in rural population. Jr Obs Gyn Ind 1985; 35: 528-33.
  7. Gupta HD: Maternal care - its importance and availability. Jr Obs Gynae Ind 1983; 30: 503-7.
  8. Amin N, Abel R, Kumar S: Maternal risk factors associated with low birth weight, Ind Jr Paed 1993; 60(2): 269-74.
  9. Ramachandran P: Risk approach to antenatal and intrapartum care. ICMR Bull 1985; 15(1).
  10. Showstack JA, Budetti PP, Minkler D: Factors associated with birth weight. An explanation of the roles of prenatal care and length of gestation. Am Jr Pub Health 1984; 74: 1003-8.
  11. Abrams B, Vickey N: Small for gestational age birth predictors and comparison with factors of spontaneous pre-term delivery in the same cohort. Am Jr Gyn and Obs 1991; 164: 785-90.
  12. Prazuck T, Tall F, Roisin AJ, Konfe S, Cot M, Lafair C: Risk factors for pre-term delivery in Burkina Faso (West Africa) Int. Jr. Epid 1993; 22(3): 489-94.
  13. Ferraz EM, Gray RH, Gurha TM: Determinants of pre-term delivery and IUGR in North East Brazil. Jr. Epid. 1990; 19: 101-8.
  14. Mavalankar DV, Gray RH, Trivedi CR: Risk factors for pre-term and term low birth weight in Ahmedabad. Int. Jr. Epidem. 1992; 21: 263-72.
  15. Randhawa I, Kanwar JS: An epidemiological study of LBW. Obst Gynae Ind 1990; 40: 62-5.
  16. Bhargava SK, Singh KK, Saxena BN: National task collaborative studies on identification of high risk families, mothers, outcome of their offsprings with particular reference to maternal nutrition, LBW, perinatal morbidity and mortality in certain urban and slum communities. ICMR publication 1990.
  17. Mamelle N, Lauman B, Lazar B: Prematurity and occupation and activity during pregnancy. Am Jr Epid 1984; 119(3): 309-22.
  18. Murphy JF: Employment in pregnancy, prevention, maternal characteristics and perinatal outcome. Lancet 1984; 1163-6.
  19. William JH: Employment in pregnancy. Lancet 1984; 2: 103-4.
  20. Samuel MJ, Kaminski M: Pregnant women at work. Lancet 1993; 1: 475
  21. Doughtery CRS, Jones AD: Determinants of birth weight. Am Jr Obs Gynae 1982; 5: 190-200.
  22. Seidman DS, Samueloff A, Mor Yosef S, Sahenkar JG: The effect of maternal age and socio-economic background on neonatal outcome. Int. Jr. Gynae Obs 1990; 33: 7.
  23. Desai P, Desai M, Hazra M: Obstetrical outcome in patients with history of spontaneous abortion. Jr. Obs Gyn Ind 1993; 43(3): 324-7.
  24. Patterson RM, Gibbs CE, Wood KC: Birth weight percentile and perinatal outcome: Recurrence of IUGR. Obs Gynae 1986; 68: 464-8.
  25. Wolfe HM, Gross TL, Sokol KJ: Recurrent SGA birth, perinatal risk and outcomes. Am Jr Obs Gynae 1987; 157: 288-93.
  26. Krishnan L, Chablader BK: Maternal risk factors and low birth weight, Jr Obst Gynae Ind 1989; 39: 52-7.
  27. Chadha VK, Bachani D, Chawla SC, Bansal RD: Nutritional status of urban poor mothers and birth weight, Jr Obs Gynae 1992; 46(6): 278-82.
  28. Badole CM, Tyagi NK, Agarwal M: Foetal growth: Association with maternal dietary intake, haemoglobin and antenatal care in rural areas. Jr Obs Gynae 1991; 1: 32-7.
  29. Bhatia BD, Sur AM, Tyagi NK: LBW babies in relation to nutritional status and primipara. Ind Jr Paed 1983; 27(3): 507.
Access free medical resources from Wiley-Blackwell now!

About Indmedica - Conditions of Usage - Advertise On Indmedica - Contact Us

Copyright © 2005 Indmedica