Independent Researcher, Johannesburg, South Africa.
School of Social Work and Social Policy, Trinity College Dublin, Dublin, Ireland.
PeerJ. 2022 Aug 29;10:e13985. doi: 10.7717/peerj.13985. eCollection 2022.
The sex ratio at birth (defined as male/(male+female) live births) is anticipated to approximate 0.510 with a slight male excess. This ratio has been observed to decrease transiently around 3-5 months following sudden unexpected stressful events. We hypothesised that stress engendered by the onset of the COVID-19 pandemic may have caused such a decrease in South Africa 3-5 months after March 2020 since in this month, South Africa reported its first COVID-19 case, death and nationwide lockdown restrictions were instituted.
We used publicly available, recorded monthly live birth data from Statistics South Africa. The most recent month for which data was available publicly was December 2020. We analysed live births for a 100-month period from September 2012 to December 2020, taking seasonality into account. Chi-squared tests were applied.
Over this 100-month period, there were 8,151,364 live births. The lowest recorded monthly sex ratio at birth of 0.499 was in June 2020, 3 months after March 2020. This June was the only month during this period where the sex ratio inverted , fewer male live births occurred. The predicted June 2020 ratio was 0.504. The observed June 2020 decrease was statistically significant = 0.045.
The sex ratio at birth decreased and inverted in South Africa in June 2020, for the first time, during the most recent 100-month period. This decline occurred 3 months after the March 2020 onset of COVID-19 in South Africa. As June 2020 is within the critical window when population stressors are known to impact the sex ratio at birth, these findings suggest that the onset of the COVID-19 pandemic engendered population stress with notable effects on pregnancy and public health in South Africa. These findings have implications for future pandemic preparedness and social policy.
出生性别比（定义为男性/（男性+女性）活产儿）预计接近 0.510，略有男性偏多。观察到这一比例在突发意外应激事件发生后 3-5 个月会短暂下降。我们假设，2020 年 3 月新冠肺炎疫情的爆发带来的压力可能导致南非在 3-5 个月后出现这种下降，因为在这个月南非报告了首例新冠肺炎病例、首例死亡病例，并开始实施全国范围的封锁限制。
我们使用了南非统计局公开提供的、有记录的每月活产儿数据。可公开获得的最新数据为 2020 年 12 月。我们分析了 2012 年 9 月至 2020 年 12 月的 100 个月活产儿数据，考虑到季节性因素。应用了卡方检验。
在这 100 个月期间，共有 8151364 例活产儿。出生性别比最低的月份记录为 2020 年 6 月，为 0.499，是 2020 年 3 月之后的第三个月。这是该期间唯一一个性别比例反转的月份，即男性活产儿较少。预测 2020 年 6 月的比例为 0.504。观察到的 2020 年 6 月下降具有统计学意义(=0.045)。
在最近的 100 个月期间，南非的出生性别比在 2020 年 6 月首次下降并出现反转。这一下降发生在南非 2020 年 3 月新冠肺炎疫情爆发后的第三个月。由于 2020 年 6 月是人口压力因素已知会影响出生性别比的关键窗口期，这些发现表明，新冠肺炎疫情的爆发带来了人口压力，对南非的妊娠和公共卫生产生了显著影响。这些发现对未来的大流行防范和社会政策具有启示意义。
