L Gindes1, R Yoeli, R Orvieto, M Shelef, Z Ben-Rafael, I Bar-Hava. 1. Department of Obstetrics and Gynecology, Rabin Medical Center (Golda Campus), 7 Kakal St, Petah Tikva 49372 and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Abstract
BACKGROUND: Fluctuations in spontaneous pregnancy rates have been observed in the general population. The purpose of this study was to evaluate whether pregnancy rates fluctuate over time in a homogeneous assisted reproduction treatment unit. METHODS: The study sample consisted of 3522 consecutive assisted reproduction cycles conducted from January 1996 to December 1999. Only fresh cycles in women <41 years old were included. All pertinent clinical data were prospectively collected on a computerized database and analysed at the end of the study. RESULTS: Throughout the 4 years of the study, monthly pregnancy rates fluctuated between 10.5 and 34.1% (mean 21.4%) per cycle, and between 13.6 and 41% (mean 27.26%) per transfer. These fluctuations did not follow any specific seasonal pattern. CONCLUSION: During routine work in an assisted reproduction treatment unit, there are random fluctuations in the pregnancy rate. This factor should be considered in studies performed in a specific time-period.
BACKGROUND: Fluctuations in spontaneous pregnancy rates have been observed in the general population. The purpose of this study was to evaluate whether pregnancy rates fluctuate over time in a homogeneous assisted reproduction treatment unit. METHODS: The study sample consisted of 3522 consecutive assisted reproduction cycles conducted from January 1996 to December 1999. Only fresh cycles in women <41 years old were included. All pertinent clinical data were prospectively collected on a computerized database and analysed at the end of the study. RESULTS: Throughout the 4 years of the study, monthly pregnancy rates fluctuated between 10.5 and 34.1% (mean 21.4%) per cycle, and between 13.6 and 41% (mean 27.26%) per transfer. These fluctuations did not follow any specific seasonal pattern. CONCLUSION: During routine work in an assisted reproduction treatment unit, there are random fluctuations in the pregnancy rate. This factor should be considered in studies performed in a specific time-period.
Authors: Amelia K Wesselink; Lauren A Wise; Elizabeth E Hatch; Ellen M Mikkelsen; Henrik T Sørensen; Anders H Riis; Craig J McKinnon; Kenneth J Rothman Journal: Hum Reprod Date: 2020-03-27 Impact factor: 6.918
Authors: Mingpeng Zhao; Haoyang Zhang; Tarah H B Waters; Jacqueline Pui Wah Chung; Tin Chiu Li; David Yiu Leung Chan Journal: Environ Health Date: 2019-11-28 Impact factor: 5.984