Results from a recent study conducted at MRC Unit The Gambia show that twins make a significant contribution to the high burden of neonatal and post-neonatal mortality in The Gambia and preventive interventions targeting this group should be prioritized. A high twinning rate and an increased risk of mortality among twins contribute to the high burden of neonatal and infant mortality in Africa. Twins have an increased risk of death during the neonatal period, and this extends at least until the first anniversary. The high rate of mortality in twins is probably due to complications at birth and early life, including prematurity and low birth weight, and cultural beliefs which can influence growth patterns and gender-biased care.

An earlier study conducted in The Gambia between 1989 and 1992 showed a twinning rate of 15 per 1000 live births and double the risk of death in this group during infancy. Since 1992, under-five mortality rate has declined in The Gambia by more than 50 %, with a similar decrease among infants (48 %) but there has been no appreciable decline in neonatal mortality (18 %). The mortality pattern in twins over this period has not been documented in the country.

The aim of this study was to examine excess mortality among twins in rural Gambia during the neonatal (within 28 days after birth) and post-neonatal periods (29 to 365 days) between 2009 and 2013, and to assess epidemiological and demographic risk factors for mortality in this group.

The study, conducted by MRC Unit The Gambia between January 2009 and December 2013 and led by Drs Reiko Miyahara, Momodou Jasseh and Anna Roca, used data from the Basse Health and Demographic Surveillance System (BHDSS), which covers the south bank of the Upper River Region of The Gambia. The BHDSS underpins all research conducted in the region and is supported by the Medical Research Council, UK, Global Alliance for Vaccines and Immunisation’s Pneumo and the Bill & Melinda Gates Foundation. The data enabled the assessment of variables for their association with mortality in different age groups. A total of 34,335 newborns were registered and included in the analysis, of whom 32,436 were singletons and 1,083 twins .

Study results show that twins represented 11.8 % of all neonatal deaths and 7.8 % of post-neonatal deaths. Mortality among twins was higher than among singletons in the neonatal period and in the post-neonatal period. Post-neonatal mortality among twins was observed to be higher in girls; those born during the dry season; and those who lack access to clean water.

Dr Momodou Jasseh, a co-author and Head of Health and Demographic Surveillance Systems at MRCG, noted that “this is yet another study that has yielded results of significant public health importance in relation to child survival and made possible by the use of health and demographic surveillance data”.

Acknowledgements
Mothers and their twin babies, BHDSS field team, London School of Hygiene and Tropical medicine and MRCG Staff

Authors
Reiko Miyahara, Momodou Jasseh, Grant Austin Mackenzie, Christian Bottomley, Jahangir Hossain, Brian Greenwood, Umberto D’Alessandro, Anna Roca

Read more about the study on the National Center for Biotechnology Information website on http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4791939/