Abstract
Aim : To study the incidence of congenital anomalies and the associated risk factors in a municipal hospital.

Method : 2188 consecutive babies born in a municipal hospital over 1 year period were assessed systematically for the presence of congenital anomalies, system wise distribution of anomalies and risk factors attributable.

Result : The incidence of congenital anomalies was found to be 3.61%. The incidence in live borns was 3.51% and in stillborns was 8%. The most common system involved was the musculoskeletal system followed by gastrointestinal and cardiac anomalies. Prematurity, increased maternal age, increasing birth order and low birth weight were found to have a higher risk of congenital anomalies.

Introduction
Congenital anomalies account for 8 to 15%^1-2 of perinatal deaths and 13 to 16% of neonatal deaths in India.^3-4 Congenital malformations are emerging as an important perinatal problem, contributing sizeably to the paerinatal mortality with considerable repercussions on the mothers and the families. Patients with multiple congenital anomalies present a relatively infrequent but tremendously difficult challenge to the paediatrician. These children have a wide array of problems including complex medical management issues, abnormalities in growth, special educational needs, behavioural and psychological problems, and cosmetic concerns. The paediatrician is faced with the challenge of making a diagnosis, pursuing therapeutic or prophylactic options, offering a prognosis and often, discussing recurrence risks with the family.

The present study was conducted to find out the incidence and spectrum of congenital anomalies and the possible risk factors in the deliveries occurring in a municipal hospital over a one year period.

Material And Methods
All babies delivered (live and still births) in a municipal hospital in a major city over a period of one year were prospectively studied. All cases taken in the study were evaluated according to a preformed proforma. Relevant information regarding maternal age, gestational age, sex, community, birth weight, birth order and consanguinity were documented. Significant antenatal history like maternal illness, ingestion of drugs, exposure to radiation and complications of labour were recorded. Antenatal USG findings were noted.

If a congenital anomaly was detected, the baby was further investigated to rule out multiple anomalies or syndromes.

The diagnosis of stillbirths with malformations was difficult because half of the stillbirths were macerated. Postmortem analysis remained the gold standard for diagnosis of internal anomalies. In the current study, only one postmortem could be performed. Two other anomalies were gross and could be detected on external appearance itself.

A malformation scan is able to pick up a lot of genitourinary and CNS anomalies. Skeletal anomalies could be picked up in the early second trimester. This can help in future for early detection of lethal anomalies.

Due to poor follow up, the karyotype could not be done for patients in the current study.

Ultrasound was employed routinely to detect multiple congenital anomalies and to rule out majority of the internal congenital anomalies. 2 D echo was also used for all congenital heart disease along with the routine X-ray chest and electrocardiogram. Other investigations were intravenous pyelonephrography and retrograde cystourography. CT and MRI were advised only for certain special cases and these cases were followed up for a period of one year.

Results (Tables 1 and 2)

Discussion
Birth defects are being diagnosed in an increasing number of infants in antenatal and neonatal period due to improved diagnostic technology especially USG. At present, congenital anomalies account for the third commonest cause of death after perinatal asphyxia and prematurity. The improvements in the obstetric management would alter the scene and with a better care of premature newborns, congenital anomalies would probably be a leading cause of death as is in the west.

The total incidence of congenital anomalies in this study was found to be 3.61% in a total of 2188 babies (Table 1), of which the anomalies in live borns accounted for 3.51% and those in stillbirths accounted for 8%. Vishnu Bhat et al have found the incidence of congenital anomalies to be 3.7%, amongst the total of 12797 babies.5 Similar findings were observed from Delhi,6 Wardha3 and Hyderabad.7 The studies conducted by K Kulshrestha et al8 in a rural population also found an incidence of 3.45%.

The sexwise distribution was 57% males and 43% females and there were 2 cases of ambiguous genitalia. Thus it showed that males were more involved than females.

This study has picked up 4 congenital anomalies in 50 cases of stillbirths, giving the total incidence of anomalies in stillbirths to be 8%. These anomalies were of anencephaly; skeletal dysplasia (Thanatophoric dysplasia) proved by X-ray diagnosis; gross multiple skeletal anomalies in a macerated stillbirth; and a case of congenital diaphragmatic hernia with pulmonary hypoplasia, which was detected at postmortem.

The commonest anomaly detected as seen in Table 2, was the musculoskeletal system[31.65%] followed by the gastrointestinal system [17.2%] and the cardiovascular system [16.46%].

Major malformations were classified as those malformations requiring medical or surgical attention or causing cosmetic abnormality to the child. This study found the incidence of major anomalies as 2.01%[ 20/1000].

As shown in Fig. 1, the incidence of congenital anomalies was statistically higher in preterm babies as compared to full term babies9 . This is particularly a cause of concern as prematurity and stillbirths are a major cause of perinatal mortality.

This study divided the maternal age into three groups i.e. less than 20 yrs, 20 to 30 yrs and more than 30 yrs.Women less than 20 years had no babies with congenital anomalies and the mothers of babies with congenital anomalies were mostly between 20 and 30 years i.e. 73% and 26.7% above 30 yrs. Thus this study has statistically showed that mothers with age more than 30 years stand at a higher risk of producing malformed babies. This study also correlates with Murphy’s observation that the incidence of congenital anomalies was constant between age groups 19 to 29 years and increases after 30 years.10 Other studies5,11 have statistically documented association of increased maternal age and congenital anomalies. It can be summarized that maternal age increases the incidence of congenital anomalies.

Low birth weight was associated with increased risk of congenital malformations [Fig. 2]. This highlights the fact that the presence of congenital anomaly itself hampers the growth of a developing foetus. This fact is also highlighted in other studies.5,12

Most babies with congenital anomalies were of the first order [40%] and the second order [34%]. The third birth order was associated with 16% of the anomalies. As for the normal babies, 36.8% belonged to the first order and 37.2% belonged to the second order. The third order comprised 22% of the babies. Above the fourth order, babies belonging to the group of congenital anomalies were 6.7% and those belonging to the fifth order were 2.7%. This was definitely more than the normal babies of fourth and fifth order who comprised 2.9% and 0.4% of the total normal births. This indicates that as the birth order increases the incidence of congenital anomalies also increases, though it was not statistically proved in this study.

Single system involvement constituted 84% of the cases as compared to 16% of multiple system involvement.

Amongst the 75 malformed babies, 15 were born of consanguineous marriages while 60 were born of non consanguineous marriage. Thus 1/5th of the total malformed babies were of consanguineous marriage.

Fig. 1 : Prematurity and congenital anomalies	Fig. 2 : Distribution of the cases and controls by birth weight

Conclusion
This study revealed that the incidence of congenital anomalies in our institute over one year period was 3.61%. The incidence in live borns was 3.51% and in stillborns it was 8%. Prematurity, increased maternal age, low birth weight, consanguinity and higher birth order were found to be associated with increased risk of congenital anomalies. Drugs were found to be teratogenic and folate deficiency was associated with neural tube defects.

Recommendations for Prevention of Congenital Anomalies

1. Use of folic acid prior to conception and before the first trimester can prevent neural tube defects.
2. Malformation scan can be used to detect lethal congenital anomalies.
3. Antenatal testing like amniotic fluid testing can be used to detect certain lethal congenital anomalies.
4. Increased maternal age is associated with increased incidence of congenital anomalies, hence maternal education and family planning play a very important role in prevention of congenital anomalies.
5. Consanguinity is associated with increased incidence of congenital anomalies, hence consanguineous marriages should be discouraged.

Acknowledgement
We acknowledge Dr Anagha Jaykar, professor in Paediatrics, who supervised this study and gave her valuable guidance.

References

1. Ravikumara M, Bhat BV, Oumachigui A. Perinatal mortality trends in a referral hospital. Indian J Pediatr 1996;63:357-61.
2. Bhat BV, Ravikumara M. Perinatal mortality in India-Need for introspection. Indian J Maternal and Child Hlth 1996;7:31-3.
3. Chaturvedi P, Benerjee KS. Spectrum of congenital malformations in the newborn from rural Maharashtra. Indian J Pediatr 1989;56:501-7.
4. Agarwal SS, Singh U, Singh PS et al. Prevalence and spectrum of congenital malformations in a prospective study at a teaching hospital. Indian J Med Res 1991;94:413-9.
5. B.Vishnu Bhat, Lokesh Babu. Congenital malformations at birth-a prospective study from south India. Indian J Pediatr 1998;65:873-81.
6. Singh M, Sharma SK. Spectrum of congenital malformations in the newborns. Indian J Pediatr 1980;47:239-244.
7. Chinara PK, Singh Shamer. East-West differentials in congenital malformations in India. Indian J Pediatr 1982;49:325-9.
8. Kulshrestha R, Nath LM, Upadhyaya P. Congenital malformations in live born infants in a rural community. Indian Pediatr 1983;20:45-9.
9. Mathur BC, Sheila Karan, Vijaya Devi KK. Congenital malformations in the newborn. Indian Pediatr 1975; 12:179-183.
10. Murphy DP. Congenital malformations. 2nd edition J B Lippincott Co., 1947.
11. Anand JS, Javadekar BB, Belani Mala. Congenital malformations in 2000 consecutive births. Indian Pediatr 1988;25:845-51.
12. Swain S, Agrawal A, Bhatia BD. Congenital malformations at birth. Indian Pediatr 1994;31:1187-91.