2WHO Scientific Group on the Epidemiolo gy of Infertility.The epidemi- ology of infertility [ R ] .In Technical Report Series.Geneva : World Health or ganization, 1975.
3Rowe PJ, Comhaire FH, Har greave TB, et al.WHO manual for the stan- dardized investigation and dia gnosis of the infertile couple [ R ].Cam- bridge : Cambridge University Press, 1993.
4van Noord-Zaadstra BM, Looman CW, Alsbach H, et al.Delaying child- bearing: effect of age on fecundity and outcome of pre gnancy [J ].BMJ, 1991,302.. 1 361-1 365.
