Akinboro A, Azeez M A, Bakare A A
Indian J Hum Genet. 2008 May;14(2):41-7. doi: 10.4103/0971-6866.44104.
In the human species, twin is a type of multiple birth in which the mother gives birth to two offspring from the same pregnancy. The occurrence and frequency of twinning, however, varies across human populations. The maternal age, socio-environmental factors, increase in the use of contraceptives, the race of human population, increase in the spontaneous abortion rate, and seasonal variations are among the factors that could influence twinning rate. Information on twinning rates in southwest Nigeria is limited.
This study presents information on the frequency of twinning, as well as its analysis by maternal age, in four urban settings in southwest Nigeria. This is with the aim of extending current knowledge on the frequency of twinning in southwest Nigeria and contributing to the demographic studies in the country.
Data on single births and twin births from January 1995 to December 2004 were collected from the Oyo State General Hospital (OSGH), Wesley Guild Hospital (WGH), Obafemi Awolowo University Teaching Hospital (OAUTH), and Ekiti State Specialist Hospital (ESSH) in Ogbomoso, Ilesa, Ile-Ife, and Ado-Ekiti respectively. These were analyzed by year and maternal age groups of 15-19, 20-24, 25-29, 30-34, 35-39, 40-44, and 45-49 years according to the standard method.
A frequency of twin births of 46.5 per 1000 deliveries and 46.2 per 1000 deliveries was recorded for Ilesa and Ile-Ife respectively. The frequency recorded for Ogbomoso and Ado-Ekiti was 38.5 and 22.1 per 1000 deliveries respectively. The overall average frequency of 40.2 per 1000 deliveries for the four hospitals ranks among the highest recorded rates of twin births in the world. The maternal age group of 25-29 years had the highest occurrence of twin births, while the lowest was recorded in the 45-49 years age group.
This analysis reveals high incidence of twinning in the studied areas and supports previous assertion that the southwestern part of Nigeria has the highest twinning rate in the country and in the whole world. It is our opinion that diet, maternal history of twinning, and some socio-environmental factors may have influenced the results.
在人类中，双胞胎是多胎生育的一种类型，即母亲在同一孕期生下两个后代。然而，双胞胎的发生率和频率在不同人群中有所不同。产妇年龄、社会环境因素、避孕药具使用增加、人群种族、自然流产率上升以及季节变化等都是可能影响双胞胎发生率的因素。关于尼日利亚西南部双胞胎发生率的信息有限。
本研究提供了尼日利亚西南部四个城市地区双胞胎频率的信息，以及按产妇年龄进行的分析。目的是扩展当前关于尼日利亚西南部双胞胎频率的知识，并为该国的人口统计学研究做出贡献。
收集了1995年1月至2004年12月期间分别来自奥约州综合医院（OSGH）、卫斯理公会医院（WGH）、奥巴费米·阿沃洛沃大学教学医院（OAUTH）和埃基蒂州专科医院（ESSH）的单胎和双胎出生数据，这些医院分别位于奥贡博索、伊莱萨、伊费和阿多-埃基蒂。按照标准方法按年份和15 - 19岁、20 - 24岁、25 - 29岁、30 - 34岁、35 - 39岁、40 - 44岁和45 - 49岁的产妇年龄组进行分析。
伊莱萨和伊费记录的双胞胎出生率分别为每1000例分娩46.5例和每1000例分娩46.2例。奥贡博索和阿多-埃基蒂记录的频率分别为每1000例分娩38.5例和22.1例。四家医院每1000例分娩40.2例的总体平均频率位列世界上记录的最高双胞胎出生率之中。25 - 29岁的产妇年龄组双胞胎出生率最高，而45 - 49岁年龄组记录的出生率最低。
该分析揭示了研究地区双胞胎的高发生率，并支持了先前的论断，即尼日利亚西南部是该国乃至全世界双胞胎发生率最高的地区。我们认为饮食、产妇双胞胎生育史以及一些社会环境因素可能影响了结果。
