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Indian Journal of Community Medicine

Maternal Determinants of Intrauterine Growth Retardation: A Case Control Study in Udupi District, Karnataka

Author(s): D. Acharya, K. Nagraj, N.S. Nair, H.V. Bhat

Vol. 29, No. 4 (2004-10 - 2004-12)

Abstract

Research question: What are the maternal determinants of intrauterine growth retardation (IUGR) in the rural community?

Objective: To study the maternal determinants of intrauterine growth retardation among cases admitted for delivery in maternity homes of rural field practice area.

Design: Case-control study.

Setting: Rural Maternity and Child Welfare Homes (RMCWH) in Udupi district, Southern Karnataka.

Participants: Mothers who underwent nornal delivery in rural maternity and child welfare homes and their neonates.

Study variables: Mother's age, parity, maternal height, maternal weight, body mass index, haemoglobin level during pregnancy, birth weight of the body.

Outcome variables: Intrauterine growth retardation.

Statistical analysis: Chi square test. OR's with 95% CI.

Results: Significant risk factors identified in univariate analysis included maternal height (<145 cms.), maternal weight (<45 kgs.), body mass index (<18.5) and anaemia in pregnancy. Multiple logistic regression analysis revealed that maternal age (>30 years), primiparity, maternal height (<145cms.) maternal weight (<45 kgs.), anaemia in pregnancy (Hb<11gm%) is the significant risk factors of intrauterine growth retardation.

Key Words: Intra Uterine Growth Retardation, Neonate

Introduction

The prevention of low birth weight is a public health priority in many developing countries1 where the condition is largely attributes to intrauterine growth retardation as compared to prematurity in developed countries2. Prematurity and intrauterine growth retardation have different risk factors and different prognosis for infant survival and long term morbidity. There have been few population-based studies on low birth weight, especially those designed to distinguish between prematurity and intrauterine growth retardation. Those that have been conducted have often had an inadequate control and lack of statistical power, resulting in inconclusive evidence for determinants of intrauterine growth retardation in developing countries.

IUGR is observed in about 23.8% of the newborn and approximately 30 million babies suffer from IUGR every year3. Nearly 75% of all affected babies are born in Asia. 20% in Africa and about 5% in Latin America. The prevalence of low birth weight in India was found to be 26%4. The proportion of IUGR was found to be 54.2% in India3.

The factors that have been postulated to influence the risk of intrauterine growth retardation among the newborn in the developing countries include pre-pregnancy weight, maternal age, maternal education, gestational weight gain, tobacco chewing, calorie intake during pregnancy, maternal height, socio-economic conditions, general morbidity, bith interval strenuous maternal work, parity, sexual activity during pregnancy, urinary tract infection, first antenatal visit, number of antenatal visits and quality of antental care5,6. However in developing countries evidence on the association between these factors and IUGR among newborn is scarce. A case-control study was therefore conducted to elucidate some of the major risk factors for intrauterine growth retardation among newborns.

Material and Methods

This case control study was conducted in the field practice area of Kasturba Medical College, Manipal. Udupi district, Karnataka. The field practice area covers a population of about 45,000 living in 6,730 families spread out in 11 villages in coastal area of Udupi taluk. Udupi district, Karanataka, India. A network of 7 Rural and Maternity and Child Welfare (RMCW) Homes located at Alevoor, Kaup, Padubidri, Malpe, Udyavara, Katpadi and Kadekar villages provide maternal and child health services. These centers are under the direct administrative control of Department of Community Medicine, Katurba Medicial College, Manipal.

Sample size

A total of 101 cases and 202 controls were selected in the study from 1st January 2002 to 31st December 2002. This gives a power of 80% for detecting an OR>2.1 as significant at 5% level if the prevalence of
exposure among controls is between 20-60%.

Selection of Cases

Cases were all the singleton newborn children with intrauterine growth retardation delivered in RMCW Homes during the study period. Intrauterine growth retardation was defined as occuring if the birth weight was below 10th percentile for gestational age on the chart of fetal growth developed by Brenner et al7.

Selection of Controls

Controls were singleton newborn babies who were appropriate for gestational age and were delivered in the RMCW Homes during the study period. After the selection of each case as defined, the next available 2 newborns that had fulfilled the criteria for controls given above were selected and included in the control group. This ensured a case : control ratio of 1:2.

Data collection

Antenatal Records of the patients who delivered in the center from January to December 2001 were scrutinized for completencess of history and case write up. Pregnancy outcome recorded in terms of LBW, IUGR, stillbirths were scrutinized and cases were selected. Information relating to maternal, socio-demographic and obstetric factors was obtained from the case records, which included age, parity, maternal height, weight and haemoglobin level.

Data analysis

Data was analyzed by the use of SPSS / PC ++. Epi-Info 5.1 software. Odds ratios with 95% confidence intervals were calculated. Since intrauterine growth retardation is a multifactorial conditions and many of the factors are inter-related, we used a multiple logistic regression analysis to assess their independent effects.

Results and Discussion

Table 1 presents the risk factors of intrauterine growth retardation on univariate analysis with OR and 95% confidence interval. Among the maternal factors : maternal malnutrition including maternal weight (<45kg.) maternal height (<145cm) and body mass index (<18.5) were significantly associated with IUGR. These findings are consistent with Kramer's meta-analysis1 and studies conducted in various developing countries5,6,8,9. In our study, maternal age had no significant association with IUGR. Our findings on maternal age as a risk factor is consistent with studies conducted Mavalankar et al6 in India and Fikree et al8 in Pakistan but a study conducted by Ferraz et al5 in Brazil has shown that young maternal age (<20 years) is a significant risk factor of IUGR. Proportion of primigravida was high among cases as compared to control but the difference was not statistically significant. In contrast, studies conducted in India6 and Pakistan8 have revealed that primiparity is significantly associated with IUGR. In our study, on univariate analysis anaemia in pregnancy (Hb <11gm%) was significantly associated with IUGR. But this finding was in contrast with Kramer's meta-analysis1 and studies conducted in various developing countries5,6,8,9.

Table I : Univariate Analysis Showing the Maternal Risk Factors for IUGR.

Maternal factors Categories Cases Controls OR (95%CI)
Number
(n=101)
% Number
(n=202)
%
Age of the mother ≤19 years 6 (5.9) 12 (5.9) 1.07 (0.39-2.96)
  20-30 years 77 (76.2) 165 (81.7) - -
  >30 years 18 (17.8) 25 (12.4) 1.54 (0.8-3.0)
Parity Primigravida 44 (43.6) 68 (33.7) 1.52 (0.93-2.48)
  Multigravida 57 (56.4) 134 (66.3) - -
MaternalHeight <145 cm 14 (13.9) 7 (3.5) 4.48 (1.75-11.5)
  ≥145 cm 87 (86.1) 195 (96.5) - -
Maternal weight <45 kg 29 (28.7) 11 (5.4) 7.0 (3.3-14.73)
  ≥45 kg 72 (71.3) 191 (94.6) - -
BMI <18.5 12 (11.9) 10 (5.0) 2.59 (1.08-6.25)
  ≥18.5 89 (88.1) 192 (95.0) - -
Anaemia < 11g% 69 (76.7) 104 (60.5) 2.15 (1.21-3.82)
  ≥ 11g% 21 (23.3) 68 (39.5) - -

Among the risk factors which influenced IUGR, maternal height (<145cms), maternal weight (<45kgs.), body mass index (<18.5) and anaemia in pregnancy (Hb<11 gms%) were found to be strongly associated with IUGR by univariate analysis. Age of the mother and parity were not significantly associated with IUGR. All these factors were subjected to multiple logistic regression analysis.

Table II presents the results of multiple logistic regression analysis showing the determinations of IUGR with adjusted OR and 95% confidence interval. The significant determinants identified for IUGR were age >30 years, primiparity, maternal height (<145 cms.), maternal weight (<45 kgs) and anaemia in pregnancy (Hb<11g%). Mavlankar et al6 in India. Fikree et al8 in Pakistan and Ferraz et al5 in Brazil reported that advanced maternal age (>30 years) and anaemia in pregnancy had no significant association with IUGR. Our findings on primiparity, maternal height (<145 cms.), maternal weight (<45 kgs) are consistent with various studies conducted in developing countries5,6.

Table II : Significant Determinants of IUGR - Results of Multiple Logistic Regression

Maternal factors Categories OR 95% CI p-value
Parity Primigravida 2.0 1.13-3.8 0.018
  Multigravida -    
Height <145 cm 4.27 1.49-12.24 0.007
  >145 cm -    
Weight <45 kg 7.04 2.87-17.29 0.001
  ≥45 kg -    
Anaemia <11g% 2.13 1.15-3.95 0.01
  ≥11g% -    

It was a maternity home records based retrospective study. About 20% of the pregnancies were referred to tertiary level hospital for caesarean section and other specialized treatment. Those cases were not included in the study. The result of the study therefore can be biased to a certain extent. Inspite of the constraints, the study provides intersting information, which can be helpful in planning maternal and child health services in rural areas. We recommend to strengthen the maternal health programmes focusing on maternal nutrition and iron and folic acid supplementation during antental period.

References

  1. Kramer M.S. Determinants of low birth weight : Methodological assessment and metaanalysis. Bull WHO 1987; 65:663-737.
  2. Villar J, Belizan J. The relative contribution of prematurity and fetal growth retardation to low birth weight in developing countries. Am J Obstet Gynecol 1982;143:793-98.
  3. Deonis M. Blossner M, Villar J. Levels and patterns of intrauterine growth retardation in developing countries. Available from http://www.unu.edu/ unupress/food2/UIDO3E/uid03e05.html
  4. WHO (1995) Bridging the gaps. The World Health Report 1995. Report of the Director General.
  5. Ferraz EM, Gray RH, Cunha TM. Determinants of preterm delivery and intrauterine growth retardation in north-east Brazil. Int J Epidomiol;19:101-08.
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  9. Pelletier D et al. Maternal anthropometry predictors of IUGR and prematurity in Malawi Maternal and Child Nutrition study. Bull WHO OMS Supplement 1995;73:81.
  10. K. Nagaraj Determinants of low birth weight - A case control study in Tirupati, India. Indian Practitioner 2003;56:4.
  11. Schlesselman J J. Case control studies : Design and conduct and analysis. Newyork Oxford University Press : 1982;171-290.
  12. Sushma Mallik, Radha G Ghidiyal, Rekha Udani and Prasad Waigankar. Maternal Biosocial factors affecting low birth weight. Indian Paediatr 1997; 64:373-77.
  13. Sumudha M. Joshi. N.P. Pai. Effect of maternal bio-social determinants on the birth weight in a slum area of greater mumbai. Indian Community Medicine XXV(3) 2000. 121-123.

Department of Community Medicine,
Kasturba Medical College,
Manipal, Karnataka - 576104, India

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