This is a prospective observational study conducted in MVJ Medical College and Research Hospital, Hoskote, Bangalore over a period of three months from August to October 2012. One hundred and twenty mothers and their healthy full term singleton neonates with uneventful perinatal periods were included in the study. All the babies were roomed in with their mothers and given exclusive breast feeding which was initiated within the first hour of birth, as per BFHI (Baby friendly Hospital initiative) policy. All the mothers received support, encouragement and supervision for breast feeding techniques and good latching. Of the 120 mother baby dyads at the start of the study, 9 dyads missed the follow up weight checks at day 7 and/or day 28; in 7 neonates exclusive breast feeding was not followed after discharge from the hospital. Hence these 16 dyads were excluded from the study and a total of 104 dyads were analysed. There were 55 neonates delivered by normal vaginal route and 49 neonates delivered by cesarean section. The weights of these babies were recorded on day 1 and day 3 (72 hours) during their hospital stay, and on day 7 and day 28 during follow up. The neonates were weighed naked using electronic baby weighing scale (Phoenix model BWS101) with resolution of 1 gram. Clinical and demographic data of the mothers and neonates in the study were recorded and analysed. Primary outcome measured was weight loss of neonates in the two groups (% of birth weight) at 24 hours and 72 hours of life. Secondary outcome was weight gain (g/kg/day) at 28 days of life.

Unpaired t-test was used for analysis of continuous variables including the baseline characteristics of the mother baby dyads. SPSS version 21 was used for statistical analysis.

Of the 104 mother baby dyads in the study, there were 51 male and 53 female neonates. Fifty five babies were delivered by normal vaginal delivery (NVD) and 49 were delivered by Cesarean section (CS). The demographic data of the mothers including the socioeconomic status and education are given in [Table/Fig-1]. The clinical characteristics of the neonates in the normal vaginal delivery and Cesarean section groups are also given in [Table/Fig-1].

The weight loss (% of birth weight) on day 1 (24 hours) and day 3(72 hours) are shown in [Table/Fig-2]. Babies delivered by CS showed a greater weight loss of 3.2% than the weight loss of 2.2% in NVD babies at 24 hours; The p-value was significant (0.0016). The corresponding weight loss at 72 hours in the CS and NVD groups were 5.9% and 4.7% respectively; the p-value was significant (0.0314).

[Table/Fig-3] shows the weight patterns in the first month of life in the two groups in g/kg/day. The weight loss on days 1, 3 and 7 were higher in the CS group than the NVD group and this was found to be statistically significant on all the three occasions with p-value <0.05. On day 28, the infants of the NVD group showed a slightly higher weight gain (11.9g/kg/d) than the CS group (10.9g/kg/d) with a significant p-value of 0.02.

The important finding of this study is the significant association between weight loss and the mode of delivery. The neonates delivered by cesarean section showed greater weight loss than those delivered by normal vaginal route (3.2% vs 2.2% and 5.9% vs 4.7% respectively) at 24 and 72 hours of life. Saki A et al., studied the effect of type of delivery on exclusively breast fed neonates who were exclusively breast fed in Shiraz, Iran. They also reported that neonates born by Cesarean section showed greater weight loss at birth and first few days of life (p-value <0.01) [10].

Mulder PJ et al., found that during postpartum hospitalization, breast fed infants showed excess weight loss (>7%) in the first two days post partum in the absence of other indicators of ineffective breast feeding [4]. Noel-Weiss J et al., in their systematic review of five electronic databases reported that mean weight loss ranged from 5.7% to 6.6% [11]. Bertini G et al., reported a mean weight loss of 5.95% in a study of full term vaginally delivered babies [12]. In the present study we found that the mean weight loss on day 3 was 4.7%. The importance of postnatal lactational counseling leading to higher weight gain in the neonatal period has been highlighted in their study by Pereira et al. They also found reduced frequency of mixed feeding among mothers who received lactational counseling [13].

There has been a worldwide rise in Cesarean section rate in the last 30 years with Caesarian section being the most common major surgery in private health sector. The rise has been seen in Indian setting and in rural areas as well [14–16]. Cesarean delivery has been reported as a barrier for initiation of breast feeding in the first hour of life. Additional intervention programs and special assistance to support breast feeding have been recommended for mothers undergoing Cesarean section [7–9]. Perez- Escamilla R et al., also reported that Cesarean section was also a risk factor for breast feeding for less than one month [8]. In our study, we found that on day 28, the NVD infants showed a higher weight gain (11.9 g/kg/d) than the CS infants (10.9g/kg/d), with a significant p-value of 0.024. However, Saki A et al., reported that neonates born by Cesarean were below that of normal vaginal deliveries till 25 days postpartum, after which Cesarean deliveries showed higher weight gain than normal vaginal deliveries [10].

The route of delivery (Cesarean section or normal vaginal route) has a significant impact on the physiological weight loss experienced by exclusively breast fed neonates in the first week of life. Neonates delivered by caesarian section showed significantly higher weight loss on days 1 and 3 of life. They also showed lower weight gain than those born by vaginal route at the end of first month of life. Mothers who undergo Cesarean section need greater support and assistance for breast feeding.