The Terrorist Attacks and the Human Live Birth Sex Ratio: a Systematic Review and Meta-Analysis

Masukume, Gwinyai; O’Neill, Sinéad M.; Khashan, Ali S.; Kenny, Louise C.; Grech, Victor

doi:10.14712/18059694.2017.94

Acta Medica > Archive > 2017, Vol. 60 > Issue 2 > The Terrorist Attacks and the Human Live…

Acta Med. 2017, 60: 59-65

https://doi.org/10.14712/18059694.2017.94

The Terrorist Attacks and the Human Live Birth Sex Ratio: a Systematic Review and Meta-Analysis

Gwinyai Masukume^a,b, Sinéad M. O’Neill^b, Ali S. Khashan^b,c, Louise C. Kenny^b, Victor Grech^d

^aGravida: National Centre for Growth & Development, University of Auckland, Auckland, New Zealand
^bIrish Centre for Fetal and Neonatal Translational Research (INFANT), Department of Obstetrics and Gynaecology, University College Cork, Cork, Ireland
^cDepartment of Epidemiology and Public Health, University College Cork, Cork, Ireland
^dAcademic Department of Paediatrics, Medical School, Mater Dei Hospital, Malta

Received January 11, 2017
Accepted April 3, 2017

Aim: The live birth sex ratio is defined as male/total births (M/F). Terrorist attacks have been associated with a transient decline in M/F 3–5 months later with an excess of male losses in ongoing pregnancies. The early 21st century is replete with religious/politically instigated attacks. This study estimated the pooled effect size between exposure to attacks and M/F. Registration number CRD42016041220. Methods: PubMed and Scopus were searched for ecological studies that evaluated the relationship between terrorist attacks from 1/1/2000 to 16/6/2016 and M/F. An overall pooled odds ratio (OR) for the main outcome was generated using the generic inverse variance method. Results: Five studies were included: 2011 Norway attacks; 2012 Sandy Hook Elementary School shooting; 2001 September 11 attacks; 2004 Madrid and 2005 London bombings. OR at 0.97 95% CI (0.94–1.00) (I² = 63%) showed a small statistically significant 3% decline in the odds (p = 0.03) of having a male live birth 3–5 months later. For lone wolf attacks there was a 10% reduction, OR 0.90 95% CI (0.86–0.95) (p = 0.0001). Conclusion: Terrorist (especially lone wolf) attacks were significantly associated with reduced odds of having a live male birth. Pregnancy loss remains an important Public Health challenge. Systematic reviews and meta-analyses considering other calamities are warranted.