Spectrum of Congenital Anomalies and associated riskfactors

Introduction

Congenital anomalies can be defined as functional or structural anomalies (metabolic disorders, for example) that take place during intrauterine life.

Identification of congenital anomalies can be done prenatally, at birth, or at times may only be detected later in infancy, such as hearing defects1. Based on the Global Report on Birth Defects (2006) global estimates on Birth Defects reports 6% of children annually. The World Health Statistics Report (2012) states that 97.8 Lakhs children are born annually with a serious birth defect worldwide and 94% of these occur in middle and low income countries. As per WHO SEARO report (2013), in India 7% of Under 5 years deaths are attributed to congenital anomalies or birth defects.²

Major anomaly is a congenital abnormality that requires medical or surgical treatment and has serious adverse effects on health and development. Individual major anomalies occur in less than 1% of the population. Collectively, they are seen in roughly 3 percent of births. Examples consist of cleft lip and trachea esophageal fistula.

Minor anomaly is a congenital abnormality that does not necessitate surgical or medical treatment, which does not critically affect health or development, and does not have any considerable cosmetic impact. Individual minor anomalies usually arise in less than 4 percentage of the population.

The occurrence of multiple minor anomalies in the same child might point toward the presence of an undiagnosed major anomaly, syndrome, or functional deficit. Normal variant is a minor anomaly that usually occurs in around 4 percent or more of the population. Webbing of the third and second toes and a single umbilical artery in an otherwise normal infant are the examples of normal variant.²

Etiology of congenital anomalies is thought to be multifactorial. Some malformations are caused by single-gene defects or multiple gene defects, while some are caused by environmental causes.³ Understanding the etiology of congenital anomalies is important in prevention and in genetic counseling and early intervention for reducing mortality and morbidity. These factors may be genetic (10–30%), environmental (5– 10%) or due to multifactorial inheritance (20–35%), while 30–45% are unknown.⁴

Congenital anomalies can lead to long-term disability, which can have major impacts on individuals, health-care systems, families and societies. Some congenital anomalies can be prevented. Regular antenatal visits, adequate folic acid or iodine intake, vaccination and avoiding consanguineous marriage or unnecessary medications are just examples of prevention methods¹.

The incidence of congenital anomalies is often under-estimated due to nonpresentation at health facilities, underreporting, deficient diagnostic capacity and poor awareness.⁵ Due to paucity of data regarding birth defects, we aimed to assess the prevalence and maternal risk factors associated with congenital anomalies among neonatal admissions in a Tertiary care Hospital.

Material and methods

A retrospective, cross-sectional observational study was done in the neonatal intensive care unit of Vani Vilas Hospital, Bengaluru Medical College and Research Institute. The live born babies with birth defects born during this period in Vani Vilas hospital, Bengaluru Medical College and Research Institute were included. Still births and intrauterine death were excluded from the study. The details of all mothers delivering babies having birth defect, like demographic profile, Obstetric history including parity, consanguinity, previous pregnancy losses and history of birth defects in previous babies was recorded.

Antenatal history of mothers, for febrile illnesses with/without rash, ingestion of drugs, first trimester folic acid supplementation, radiation exposure, co morbidities like gestational diabetes, hypertension and thyroid disease etc was also taken. Labor details like onset of labor pains, premature rupture of members, mode of delivery, and duration of labor was documented.

After delivery demographic profile of babies was taken and a detailed newborn examination was done at birth to detect any visible birth defects in all live newborns, by the attending Pediatrician. Any newborn with visible birth defects was further examined for the presence of other congenital anomalies both clinically and by imaging studies whenever indicated. The data of all such newborns were collected and recorded.

Data was entered into excel data sheet and this data collected was statistically analyzed and the percentage distribution was calculated.

Results

Out of 7666 neonates, born during this period 97 neonates were found to have congenital anomalies with the prevalence being 1.1%. 57.7 % (56) were males, 40.2% (39)females and 2.1%(2) had ambiguous genitalia. 79(81.4%) of the newborns having congenital anomalies were term i.e., >37weeks and 18(18.6%) were preterm less than 37weeks.

Majority of the newborns with congenital anomalies weighed >2.5kg (57.7%) . 58 (69%) babies born to multigravidas mother and 26(31%) babies born to Primigravida had birth defects. With respect to maternal age, birth defects were highest, 52 (61.9%) among neonates born to mothers aged between 20 to 24 years of age.

Among the maternal risk factors, birth defects were seen in 16 newborns (44.4%), 12(33.33%), 6 (16.66%) and 2(5.55%) with Anemia, Hypertension, Gestational Diabetes and Multiple pregnancy respectively. Consanguinity was seen in 7.2% of the cases.⁷ History of previous spontaneous abortions was present in 15.5% cases. Out of the 97 newborns with congenital anomalies 17 died (17.5%).

The predominant system involved was circulatory system (27%) which was followed by musculoskeletal system and Central nervous system (22% and 13% each). Ostium Secundum Atrial septal defect was most common cardiovascular anomaly. Congenital diaphragmatic hernia was most common in musculoskeletal anomalies and lumbar meningomyelocele was most common central nervous system anomaly.

Discussion

The aim of this study was to determine the pattern of congenital anomalies and associated maternal risk factors. Multiple known and unknown factors including genetic, environmental, racial and ethnic factors play role in determining the prevalence of congenital anomalies.7The overall prevalence of congenital anomalies in our study was 1.26% which was low when compared to other studies in India which reported prevalence of 2.22% and 1.9%.8, 9If the abortions and stillbirths were included, the prevalence of congenital anomaly would have been much more than the present rate.

It was noted that that majority of babies with malformations were born to mothers of age group 20-24years. It was relatable to other studies done in India^8,10. In majority of the studies the relationship between age of the mother and incidence of congenital anomalies was insignificant. Prior studies have reported considerable higher incidence of malformations among the multiparas.^8,13 Our result is consistent with this finding, which indicates higher incidence of congenital anomalies in multipara than primipara. .The study by Gupta and Verma observed history of previous abortions, anemia, hydramnios and preeclampsia to be associated in mother’s with anomalous babies^15,16. In our study there were few common risk factors of which anemia was most common (19%), hypertension (14.2%), Diabetes (7.1%) and multiple gestation (2.3%).

Congenital anomalies were more common in males than females in the our study which was similar to the other studies.1^3,14It was noted that Low Birth Weight and Very Low Birth Weight comprised of 42.2% of the total babies with congenital malformations. Whereas in other studies it was associated with higher risk of congenital malformations.¹³

In our study, the most common system involved was circulatory system(27%) followed by musculoskeletal system(22%) , Central nervous system (13% ), Orofacial malformations( 11%) ,Gastrointestinal system(10%), etc., This was similar with the studies conducted by others.^8,11 . In some studies there was higher incidence of CNS malformations followed by musculoskeletal system.10In a study conducted by Suguna Bai et al, GI malformations were the most common.¹²

Limitations

Abortions and stillborns weren’t included, because often the abnormalities are not visible externally or obvious. In those cases, a pathological autopsy is required and in majority of the cases, parental consent is not obtainable. As this was a hospital based study it cannot be generalized to the general population. This study sought to detect mostly only the external congenital anomalies among neonates by clinical examinations to make a diagnosis.

Conclusion

This study has emphasized the prevalence, types and maternal risk factors associated with congenital anomalies seen in our hospital. It will help in creating awareness about the occurrence and risk factors associated with congenital malformations through health education. This study did not provide direct benefits to study participants, but we recommend that future studies should provide information to both help women prevent congenital anomalies and improved management of patients with congenital anomalies. More research is needed to identify possible factors responsible for the various types of congenital anomalies, and future studies are recommended to evaluate specific groups of congenital anomalies, including their risk factors and prevalence rate.