Academic Head, Dept of ObGyn, University of Malta.
Consultant Paediatrician, University of Malta.
Acta Medica (Hradec Kralove). 2022;65(2):66-70. doi: 10.14712/18059694.2022.20.
The sex ratio at birth (male/total = M/F) is expected to approximate 0.515. Stress is known to reduce livebirth M/F. In the first half of the 20th century, Malta was stressed by two World Wars.
This study was carried out in order to analyse changes in reproductive performance and M/F of stillbirths and livebirths in Malta during this period.
Livebirth and stillbirth data (1910-1951) were obtained from official published Maltese government reports. Stillbirths were defined as any antenatal loss after 28 weeks of gestation.
This analysis studied 347,562 live and 11,662 stillbirths. For 1919-1951, M/F at birth was 0.517, stillbirth M/F was 0.664, implying 28/40 M/F = 0.522. Assuming conceptional M/F = 0.5, estimated M/F for fetal wastage before 28 weeks was approximately 0.434. There was a decrease in the overall birth rate starting after 1911 to 1921, more marked for 1941-1943 followed by an overshoot in 1943-48. There was a statistically significant drop in M/F livebirths during the periods 1916-21 and 1934-45. Stillbirths decreased significantly after 1935 (M>F). A stillbirth M/F drop in 1937-45 and rise in 1946-51 were statistically significant.
Birth rate drops in both wars were ascribed to conscription, adverse living conditions and decreased fertility from nutritional restrictions. Both conflicts resulted in short post-war baby booms. The decrease in stillbirths is attributed to increase in antenatal attendances, hospital births and special food rations for pregnant women. The M/F observations suggest that the selective survival of both healthier female and male foetuses is favoured during times of stress.
出生性别比（男性/总数= M/F）预计接近 0.515。压力已知会降低活产儿的 M/F。在 20 世纪上半叶，马耳他受到两次世界大战的压力。
本研究旨在分析这一时期马耳他生殖性能和死产儿及活产儿 M/F 的变化。
活产儿和死产儿数据（1910-1951 年）来自官方公布的马耳他政府报告。死产儿定义为妊娠 28 周后任何产前损失。
本分析研究了 347562 例活产儿和 11662 例死产儿。1919-1951 年，出生时 M/F 为 0.517，死产儿 M/F 为 0.664，意味着 28/40 M/F=0.522。假设受孕 M/F=0.5，估计妊娠 28 周前胎儿丢失的 M/F 约为 0.434。自 1911 年至 1921 年，总出生率开始下降，1941-1943 年更为显著，随后 1943-48 年出现过度增长。1916-21 年和 1934-45 年期间，活产儿 M/F 有统计学意义的下降。1935 年后（M>F）死产儿显著下降。1937-45 年死产儿 M/F 下降和 1946-51 年上升具有统计学意义。
两次战争中的出生率下降归因于征兵、生活条件恶劣和营养限制导致的生育率下降。两次冲突都导致了战后婴儿潮的短暂出现。死产儿数量的减少归因于产前就诊次数的增加、医院分娩和孕妇特殊食品配给的增加。M/F 的观察结果表明，在压力时期，健康的女性和男性胎儿的选择性存活更有利。
