Extent of thermal stress in newborns in maternity wards and factors affecting it

INTRODUCTION

Concerns about thermal stress and its link to morbidity and mortality in neonates were first documented in 1907, but it was not until 1958, that Silverman.et.al. demonstrated the association between more effective temperature regulation and decreased mortality.¹ Neonatal hypothermia is an important contributing factor to neonatal mortality and morbidity in both developed and developing countries.² A foetus in uterus is generally 0.5^oC higher than mothers’ temperature and rapid cooling occurs after delivery, resulting in cold stress.

On the other hand, rise in temperature are seen occasionally on third or fourth day of life in newborns who are otherwise well, and overheating and sepsis as causes of fever must be excluded.³ Dehydration is perhaps an infrequently recognized cause of fever in newborn period. Sweating can occur in term and late preterm infants (35 weeks onwards), therefore they are able to raise their evaporative losses. However, maximal sweating rate is again related to gestational age.⁴

Due to the launch of various schemes under National Health Mission, total number of institutional deliveries has increased over the years, leading to an overall increase in burden over facility based care, which provides care in the form of SNCU, NBSU, NBCC and postnatal ward care. Thermal care of newborns especially in hours immediately after birth i.e. in postnatal or maternity wards is essential to protect the newborns from thermal stress and its complications, further decreasing the burden of critical care units. Neonatal health promotion programmes need to focus on behavioural changes necessary to optimize thermal care in post natal wards especially of low resource settings. Keeping these facts in mind this study is being conducted.

METHODS

The present study was conducted in two different government health centers of one of the city of Central India: Maternity ward, of Medical College Hospital (teritiary health centre) and maternity ward of, prasutigrah under department of health (primary health centre) between August 2014 to July 2015. Ethical approval for this study was obtained from Institutional Ethical Committee of hospital. The study was conducted in newborns with their mothers, in first week of life, in maternity wards of the health centers. Written and informed consent was obtained from the parents or legal guardians prior to study.

Inclusion criteria

• • All neonates with their mothers in postnatal ward.
• • All neonates upto first seven days of age (168 hours).

Exclusion criteria

• • Neonates admitted in NICU/SNCU.
• • Neonates beyond seven days of age.

Digital thermometers were used to take the axillary temperature of the neonates, which were timely standardized with mercury thermometers for accuracy Readings were taken on a randomly selected day, twice a week, alternatively in the two institutions, thus 8 times in a month, throughout the year. Each time 10 neonates were enrolled by random selection method in maternity wards. Thus making 20 each week and 80 each month with an enrollment of total 960 neonates for the whole year (480 in each health center). Baseline characteristics of the neonate i.e, (postnatal age, birth weight, gestational age at birth, sex, time of initiation of breast feeding, layers and types of cloth worn and wrapped, use of cap and socks, frequency of feeding, frequency of micturition) and mother, i.e (age, education, working status, parity, mode of delivery, socioeconomic profile) and other habits (application of oil, bathing, proximity with mother) were noted down in the proforma. Conclusions were drawn statistically to correlate the outcome.

RESULTS

p<0.001 - significantly more hypothermia in Primary health center.

Incidence of hypothermia in teritiary health center and primary health centre was 30.8% and 44.40% respectively with a P <0.001, showing significantly more hypothermia in primary health centre. Incidence of hyperthermia was 9.6% and 9.4% in teritiary health centre and primary health centre respectively with a P= 0.91 (Figure 1, Table 1).

Hypothermia was significantly high in preterm in comparison with term neonates.

The mean neonatal body temperature was found significantly lower in pre terms (mean NBT = 36.350C) than in terms (mean NBT = 36.640C) with a P = 0.031 (Table 2).

Kuppuswami scale for socioeconomic classification was used, based upon the details given by the parents of the neonates and hypothermia was significantly found more in neonates of mothers belonging to low socioeconomic status i.e, lower and upper lower class (P = 0.049) (Table 3) and in mothers whose age was <25 years (P=0.011) (Table 4).

Hypothermia was seen higher in newborns of young mothers, (<25 years). No correlation was seen with hyperthermia and maternal age.

Incidence of hypothermia was found less when breastfeeding got initiated within 1 hour (P =0.006). No significant correlation of the above factors was seen with hyperthermia (Table 5).

A cloth score was formulated, taking into consideration the layers and types of cloth worn and wrapped and considering the presence of cap and socks, substituting 1 for cotton layer,2 for woolen layer,1 for the presence of cap and 1 for socks. Throughout the year, the cloth score ranged from 2 – 12. Hypothermia was significantly more when the cloth score dropped below 5 during winters (November - February) (P <0.001). No such correlation of cloth score was found in the other months and with hyperthermia (Table 6).

P < 0.001, if cloth score <5 in months of November – February

No significant correlation was found with maternal literacy, parity, mode of delivery, frequency of breastfeeding, birth weight, oil application, proximity with mother, sex and age of the baby.

DISCUSSION

Incidence of hypothermia reported in the present study is very high which ranges from 30.8% - 44.4% (Figure 1) in the maternity wards of the study hospitals which is similar to the incidence (37%) found in a hospital based study done by Suman RP et al in Mumbai.⁵ Incidence of moderate hypothermia ranges from 7.7%-18.8% in the present study (Table 1) which is higher than those reported by Kaushik et al in Shimla (2.9%).⁶ This could be because of lesser sensitivity to ambient temperature variability in central part of the country. A more recent population based study done by Darmstadt et al in Uttar Pradesh, reported hypothermia in 45% of the infants which is higher than the incidence found in this study, which could be the effect of institutional care of the neonates in this study.⁷

The study found significant difference in incidence of hypothermia in the two study health centers with a P <0.001.This may be attributable to the low resource availability at health centre 2 and in comparison to 1 (Figure 1).

Preterms were found more hypothermic than terms (Table 2) showing their lower abilities to maintain body temperatures which was similar to that reported by Mullany LC in Nepal.⁸

No significant correlation of hypothermia was found with birth weight of the neonates, which is in contrast to other studies which reports hypothermia more in low birth weight children.^9,10 This can be attributed to the exclusion of VLBW neonates who require admission in NICU and inclusion of only LBW and normal birth weight neonates in the study.

In the present study, we found significant correlation of lower socioeconomic status of mothers and incidence of hypothermia in their babies. (P = 0.049) (Table 3) which may be due to poor resource availability. Also, newborns of younger mothers were found more hypothermic (P=0.011) (Table 4) suggesting ignorance and less awareness regarding newborn care which is similar to the observations of Mullany LC.⁸

Incidence of hypothermia was found more if breastfeeding was initiated after 1 hour which is similar to that reported in other studies showing benefits of colostrum (Table 5).⁸ But no such correlation was seen with the frequency of breast feeding, probably due to variability in the amount taken during each feed according to the body weight.

The present study also suggested a correlation of lower cloth score (<5) with hypothermia during the months of November – February (P <0.001) showing the significance of more layers of cloth in maintaining body temperature during winters. No correlation of cloth layers with hyperthermia was seen which is in contrast to the study done by Basil et al in Iraq (Table 6) ¹¹

Overall incidence of hyperthermia in this study ranges from 9.4% - 9.6% and cases were found throughout the year, with no significant difference seen in both institutes which can be attributable to the presence of sepsis (Figure 1).

No correlation was found in the prevalence of thermal stress (both hypothermia and hyperthermia) with maternal literacy, sex of the neonate, mode of delivery, birth order, practices like oil application, proximity of baby with their mothers and frequency of breast feeding.

ACKNOWLEDGEMENTS

Authors would like to thank Dr. Ajay Gaur and Dr. Neelam Rajput for their support during this study.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: The study was approved by the Institutional Ethics Committee

REFERENCES

1. 1. Budin P. La Mortalité Infantile dans les Bouches-du-Rhone. Obstetrique. 1907;304-45.
2. 2. Kumar V, Shearer JC, Kumar A, Darmstadt GL. Neonatal hypothermia in low resource settings: a review. J Perinatol. 2009 Jun;29(6):401.
3. 3. Voora S, Srinivasan G, Lillien LD, Yeh TF, Phildes RS. Fever in full term newborns in the first four days of life. Pediatrics. 1982;69:40-4
4. 4. Knobel RB, Holditch-Davis D. Thermoregulation and heat loss prevention after birth and during neonatal intensive care unit stabilisation of extremely low-birthweight infants. Advances in Neonatal Care. 2007;10(58):S7-S14.
5. 5. Suman RP, Udani R, Nanavati R. Kangaroo mother care for low birth weight infants: a randomized controlled trial. Indian Pediatr. 2008;45:17-23.
6. 6. Kaushik S, Grover N, Parmer VR, Grover PS, Kaushik R. Neonatal morbidity in a hospital at Shimla. Indian J Pediatr. 1999 Jan 1;66(1):15-9.
7. 7. Darmstadt GL, Kumar V, Yadav R, Singh V, Singh P, Mohanty S et al. Introduction of community-based skin-to-skin care in rural Uttar Pradesh, India. Journal of Perinatology. 2006 Oct;26(10):597.
8. 8. Mullany LC, Katz J, Khatry SK, LeClerq SC, Darmstadt GL, Tielsch JM. Neonatal hypothermia and associated risk factors among newborns of Southern Nepal. BMC Med. 2010;8:43.
9. 9. Nayeri F, Nili F, Amini E, Khanafshar N, Zayeri F, Palizian P et al. Neonatal hypothermia in Tehran, Iran:Incidence, severity and death rate. MJIRI. 2005;19(1):23-7.
10. 10. Majumdar R, Agarkhedkar SR, Ganguli SK, Gupte A. A study of neonatal hypothermia in medical college hospital. Perspect Issues. 2005;28(1):32-9.
11. 11. Hanoudi BM. Factors contributing to dehydration fever in neonate, a teaching hospital study. Iraqi J Comm Med. 2012;3:248-52.