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. 2022 May 19;12(5):e056112.
doi: 10.1136/bmjopen-2021-056112.

Does higher early neonatal mortality in boys reverse over the neonatal period? A pooled analysis from three trials of Nepal

Seema Subedi  1 , Joanne Katz  2 , Daniel Joseph Erchick  2 , Andrea Verhulst  3 , Subarna K Khatry  4 , Luke C Mullany  2 , James M Tielsch  5 , Steven C LeClerq  2   4 , Parul Christian  2 , Keith P West  2 , Michel Guillot  3
Affiliations

Does higher early neonatal mortality in boys reverse over the neonatal period? A pooled analysis from three trials of Nepal

Seema Subedi et al. BMJ Open. .

Abstract

Objectives: Neonatal mortality is generally 20% higher in boys than girls due to biological phenomena. Only a few studies have examined more finely categorised age patterns of neonatal mortality by sex, especially in the first few days of life. The objective of this study is to examine sex differentials in neonatal mortality by detailed ages in a low-income setting.

Design: This is a secondary observational analysis of data.

Setting: Rural Sarlahi district, Nepal.

Participants: Neonates born between 1999 and 2017 in three randomised controlled trials.

Outcome measures: We calculated study-specific and pooled mortality rates for boys and girls by ages (0-1, 1-3, 3-7, 7-14, 14-21 and 21-28 days) and estimated HR using Cox proportional hazards models for male versus female mortality for treatment and control groups together (n=59 729).

Results: Neonatal mortality was higher in boys than girls in individual studies: 44.2 vs 39.7 in boys and girls in 1999-2000; 30.0 vs 29.6 in 2002-2006; 33.4 vs 29.4 in 2010-2017; and 33.0 vs 30.2 in the pooled data analysis. Pooled data found that early neonatal mortality (HR=1.17; 95% CI: 1.06 to 1.30) was significantly higher in boys than girls. All individual datasets showed a reversal in mortality by sex after the third week of life. In the fourth week, a reversal was observed, with mortality in girls 2.43 times higher than boys (HR=0.41; 95% CI: 0.31 to 0.79).

Conclusions: Boys had higher mortality in the first week followed by no sex difference in weeks 2 and 3 and a reversal in risk in week 4, with girls dying at more than twice the rate of boys. This may be a result of gender discrimination and social norms in this setting. Interventions to reduce gender discrimination at the household level may reduce female neonatal mortality.

Trial registration number: NCT00115271, NCT00109616, NCT01177111.

Keywords: Community child health; EPIDEMIOLOGY; NEONATOLOGY.

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Conflict of interest statement

Competing interests: None declared.

Figures

Figure 1
Figure 1
Sex difference in probability of dying for individual studies: NNIPS-3, CHX and NOMS (from left to right). CHX, Chlorhexidine Study; NNIPS, Nepal Nutrition Intervention Project Sarlahi; NOMS, Nepal Oil Massage Study,
Figure 2
Figure 2
Sex difference in probability of dying for pooled analysis, Nepal 1999–2017.
See this image and copyright information in PMC

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