Profile of Macrosomic Babies at a Tertiary Level Hospital

Address for correspondence: Dr. Subhash C. Shah, Lecturer Department of Paediatrics, KIST Medical College, Lalitpur, Nepal. E-mail: subashshah2012@gmail.com Tel: +9779841243117 1Dr. Subhash Chandra Shah, Lecturer, 2Dr. Devendra Shrestha, Associate Professor, 3Dr. Ajaya Kumar Dhakal, Lecturer, 4Dr. Arati Shakya, Lecturer, 5Dr. Henish Shakya, Lecturer. All from the Department of Paediatrics, KIST Medical College, Lalitpur, Nepal, 6Dr. Amita Pradhan, Professor, Department of Community Medicine, KIST Medical College, Lalitpur, Nepal. Abstract


Introduction
L ow birth weight babies have a racted much more a en on to medical prac oners, and a lot of resources and researches have been directed toward improving their morbidity and mortality.However in developing countries, the increase in frequencies of obesity and diabetes in pregnant women has led to the trend of a consistent increase in the mean birth weight and in the propor on of macrosomia 1 .Macrosomia in developing countries has been recognized as a public problem as it could increase in future 1 .In addi on, the deliveries of macrosomic babies are associated with increased perinatal morbidity and mortality secondary to perinatal asphyxia, hypoglycaemia, hyperbilirubinaemia, sepsis and trauma 2 .
Diff erent geographic popula ons have diff erent prevalences of macrosomia as documented by various previous studies 1,3 .However, there is scarcity of published studies in Nepal that use local intrauterine foetal growth curve 4 to determine the prevalence and adverse neonatal outcomes associated with macrosomia.The objec ve of this study was to es mate the incidence of macrosomia in a ter ary care level teaching hospital of Nepal based on local intrauterine foetal growth percen le according to gesta onal age specifi c to local curves, risk factors for neonatal morbidity and mortality of macrosomia and outcome of macrosomia.

Material and Methods
This was a descrip ve observa onal study done on live macrosomic babies delivered at 37 to 42 completed weeks of gesta on at KIST Medical College Teaching Hospital (KISTMCTH), a 700 bedded ter ary level care hospital located at Lalitpur district of Nepal.The study period was four years from 17 th July, 2010 to 16 th July, 2014.Macrosomia was defi ned as birth weight of 4000 grams or greater than 90 th percen le according to gesta onal age specifi c local curves 5 .Mul ple birth and s llbirths were excluded.
The hospital records of macrosomic babies were reviewed for maternal demographic profi le, medical condi on of the mother and mode of delivery.Maternal demographic characteris cs were age, gravida, period of gesta on, and associated co morbidity condi ons.Details of the macrosomic babies evaluated were gesta onal age at delivery, birth weight, gender and Apgar score.All the macrosomic babies were followed up ll the me of discharge from the hospital.The macrosomic babies, needing admission into the neonatal care unit due to one or more morbidi es, were considered as complicated ones.Risk factors associated with complica ons and fi nal outcomes of these babies were analyzed.
Data were entered and analyzed using the Sta s cal Package for Social Science (SPSS) 17.0 version (Chicago IL, USA), chi-square and Fisher's Exact test was used to determine the signifi cance of maternal and neonatal risk factors associated with neonatal complica on.
Approval to conduct the study was taken from the ins tu onal review commi ee (IRC) of KIST Medical College.

Results
During the study period, a total of 2922 live term singleton deliveries occurred.Among them, 342 (11.7%) babies were found to be macrosomic.
The maternal age of the majority of macrosomic babies was between 20 to 34 years (86.5%)(Table1).The average period of gesta on at delivery was 38.87±1.26weeks.More than 60% of the mothers were mul parous and 7% of macrosomic mothers had associated co-morbidi es.The common co-morbidi es associated in the mothers with macrosomic babies were pregnancy induced hypertension (5%) followed by intrahepa c cholestasis of pregnancy (0.6%) and eclampsia (0.6%).Maternal diabetes mellitus however was seen in only one case.The percentage of babies delivered by caesarean sec on was higher than normal vaginal delivery (50.6% versus 48.0%).
About two third of macrosomic babies were male (Table 2).The mean birth weight was 3650 grams and 12.3% weighed 4000 grams or more.The 1 minute Apgar score was less than 7 in 3.8% of babies and more than 99% of babies had 5 minute Apgar score of greater than 6.
The neonatal complica ons associated with macrosomia were seen in 19.6% of babies warran ng admission into the neonatal care unit.The maximum neonatal complica ons were seen in babies of mul gravida, medical complica ons, age <20 years and ≥35 years, caesarean sec on or instrumental delivery (Table 2).Similarly, male gender, birth weight ≥ 4000 grams, < 7 Apgar score at 1 minute and 5 minute were associated with greater neonatal complica ons (Table 2).The sta s cal analysis using chi-square and Fisher's Exact test showed that the risk factors signifi cantly associated with neonatal complica on were caesarean sec on or instrumental delivery compared to vaginal delivery (p value 0.002)and Apgar score less than 7 compared to Apgar score greater than ≥7 at 1 minute (p value 0.005).
The most common neonatal complica on was neonatal sepsis (11.4%) followed by signifi cant hyperbilirubinaemia (2%) and transient tachypnoea of newborn (1.6%) (Table 3).However, almost all cases were discharged without any sequel except for one with overwhelming sepsis who was referred to other centre on parents' request and could not be followed up hence the outcome was unknown.In this study, there was no neonatal mortality.

Discussions
The incidence of macrosomia in our study was 11.7 %.This is higher than a recent study done in developing countries of Asia including Nepal (9%) where iden fi ca on of macrosomia was done on the basis of mean birth weight cut-off irrespec ve of gesta onal age 1 .This study included the babies with birth weight either greater than 4000 grams irrespec ve of gesta onal age or birth weight greater than the 90 th percen le for gesta onal age popula on specifi c.
In the context of this study, the incidence of neonatal complica ons was seen in 67 macrosomic babies (19.6%) necessita ng admission into the neonatal care unit.The incidence of complicated macrosomia varies greatly in previous studies.According to Onalo et al, 39.5% of macrosomic babies had neonatal complica ons 2 .In another study the neonatal complica ons were seen in only 3.9% macrosomic babies 6 .However, it has been reported that the neonatal complica on in macrosomic babies is higher compared to normosomic babies in study done by Linder et al 7 .
Various maternal as well as neonatal factors were evaluated for the associated neonatal complica ons.Regarding maternal factors, it was seen that babies born via caesarean sec on or instrumental delivery had sta s cally signifi cant neonatal complica ons, which could be due to the fact that indica ons for these deliveries could be due to pre exis ng fetal compromise like foetal distress, pre-labor rupture of membrane, antepartum haemorrhage, prolonged labor etc. leading to poor outcome.In fact, most of the babies with neonatal complica ons were delivered via caesarean sec on rather than vaginal delivery (27.2% versus 11.6%) with low Apgar score at 1 and 5 minute.Similar results in babies born via caesarean sec on were found in previous studies 2,8 .Similarly regarding neonatal characteris cs, the macrosomic babies with Apgar score of ≤6 at 1 had sta s cally signifi cant neonatal complica ons.However it has been reported in previous study that the incidence of neonatal morbidity in babies with birth weight ≥3500grams was signifi cantly increased with low Apgar at 5 minute 9 .
This study showed that macrosomic babies had higher rates of neonatal sepsis, hyperbilirubinaemia and transient tachypnoea of the newborn.Neonatal sepsis is the leading cause of morbidity in Nepal 10 .The prevalence of neonatal sepsis has been reported up to 52% in Nepal 11 .This study showed that even in macrosomia the major cause of neonatal morbidity is sepsis (11.4%).In another study done in developing country, almost similar incidence of sepsis in macrosomia was reported (8.9%) 2 .There is also evidence from previous study done in Nepal that delivery via caesarean sec on and low Apgar score at 1 and 5 minute were predictors of neonatal sepsis 10 .

Signifi cant
hyperbilirubinaemia requiring phototherapy was one of the common neonatal complica ons seen in this study..Moreover a signifi cantly higher incidence of neonatal complica ons was seen in male babies in this study.Medical literature also reported that male babies delivered via caesarean sec on have increased risk of developing transient tachypnoea of new born 12 .
In this study the incidence of perinatal asphyxia including hypoxic ischaemic encephalopathy was 0.6%.The lower and higher incidence rate of perinatal asphyxia 0 % and 13.6% respec vely were reported by Lipscomb et al and Nav et al 6,13 .In contrast to our study, only 22% of macrosomic babies were delivered via caesarean sec on in study by Nav et al 6 .
The incidence of neonatal hypoglycaemia was low (0.3%) in this study.Unlike several studies where maternal diabetes was the major risk factor associated with macrosomia 1,3 , we found only one case of maternal diabetes associated with macrosomia.The low incidence of neonatal hypoglycaemia compared to previous studies could be explained by low incidence of maternal diabetes in our study.It has been reported that symmetric macrosomic newborns of non-diabe c mothers had a similar hypoglycaemic rate compared to normosomic infants (0.3%) 7 .Again, according to Linder et al, the incidence of hypoglycaemia varies with birth weight, ranging from 0.8% in infants with a birth weight of 4000-4499 g to 25% in infants with a birth weight of ≥5000 g 7 .There were only 12.3% macrosomic babies weighing 4000 grams and more in this study.
There were no cases of birth injuries in the neonates.Similar result was reported by Ezegwuiv et al 14 .Birth injuries are posi vely associated with increase in birth weight.The newborns with birth weight 4500 g or heavier carried six mes higher risk of birth trauma 15 .The absence of birth injuries compared to other studies 2,13 could also be due to the high rate of caesarean deliveries in this study.
This study has some limita ons.First, maternal body mass index (BMI) is known to be associated with macrosomia and neonatal morbidity and mortality 16 .Maternal BMI could not be calculated in this study because only maternal weight was men oned in the case sheets and not height.Secondly we were unable to classify the macrosomic babies into symmetrical and non-symmetrical subgroups based on weight length ra o due to unavailability of length of babies.It has been reported that neonatal complica ons like polycythaemia, hypocalcaemia is rare in symmetrical macrosomic babies 7 .

Conclusion
The prevalence of macrosomia was comparable as that of other developing countries.Macrosomic babies born via caesarean sec on or instrumental delivery or with low ini al Apgar had higher incidence of complica ons.Therefore, in developing countries like Nepal, neonatal sepsis is the major cause of morbidity even in macrosomic babies.Importance of early interven ons for preven on and management of macrosomic babies with neonatal sepsis needs to be emphasized.

Table 1 :
Comparison of maternal risk factors among uncomplicated and complicated macrosomic babies

Table 2 :
Comparison of neonatal risk factors among uncomplicated and complicated macrosomic babies