BACKGROUND: We aimed to evaluate whether emergency contraception with levonorgestrel (LNG-EC) administered after ovulation is equally effective to LNG-EC administered before ovulation. STUDY DESIGN: We studied a cohort of women attending a family planning clinic for EC. From interview, we recorded menstrual history, time of intercourse and of intake of LNG-EC. On the day of intake of LNG-EC and during 5 days' follow-up, blood samples were taken for examination of luteinizing hormone, estradiol and progesterone concentrations, and vaginal ultrasound examinations were done for size of the leading follicle and/or corpus luteum. Thereafter women were not contacted until next menses or pregnancy occurred. RESULTS: Of 388 women attending for LNG-EC, 122 women had intercourse on fertile cycle days according to ultrasound and endocrine findings. At the time of LNG-EC intake, 87 women were in Days -5 to -1 and 35 women were in Day 0 (day of ovulation) or beyond. With the use of the probability of clinical pregnancy reported by Wilcox et al. [N Engl J Med 333 (1995) 1517-1521], expected numbers of pregnancies among the 87 and 35 women were 13 and 7, respectively, while 0 and 6 pregnancies, respectively, occurred. CONCLUSION: We conclude that LNG-EC prevents pregnancy only when taken before fertilization of the ovum has occurred.
BACKGROUND: We aimed to evaluate whether emergency contraception with levonorgestrel (LNG-EC) administered after ovulation is equally effective to LNG-EC administered before ovulation. STUDY DESIGN: We studied a cohort of women attending a family planning clinic for EC. From interview, we recorded menstrual history, time of intercourse and of intake of LNG-EC. On the day of intake of LNG-EC and during 5 days' follow-up, blood samples were taken for examination of luteinizing hormone, estradiol and progesterone concentrations, and vaginal ultrasound examinations were done for size of the leading follicle and/or corpus luteum. Thereafter women were not contacted until next menses or pregnancy occurred. RESULTS: Of 388 women attending for LNG-EC, 122 women had intercourse on fertile cycle days according to ultrasound and endocrine findings. At the time of LNG-EC intake, 87 women were in Days -5 to -1 and 35 women were in Day 0 (day of ovulation) or beyond. With the use of the probability of clinical pregnancy reported by Wilcox et al. [N Engl J Med 333 (1995) 1517-1521], expected numbers of pregnancies among the 87 and 35 women were 13 and 7, respectively, while 0 and 6 pregnancies, respectively, occurred. CONCLUSION: We conclude that LNG-EC prevents pregnancy only when taken before fertilization of the ovum has occurred.
Authors: Alexia Hermanny; M Valeria Bahamondes; Francisco Fazano; Nadia M Marchi; Maria Elena Ortiz; Maria Heloisa R R Genghini; Horacio B Croxatto; Luis Bahamondes Journal: Reprod Biol Endocrinol Date: 2012-01-30 Impact factor: 5.211
Authors: María Eugenia Monge; Prabha Dwivedi; Manshui Zhou; Michael Payne; Chris Harris; Blaine House; Yvonne Juggins; Peter Cizmarik; Paul N Newton; Facundo M Fernández; David Jenkins Journal: PLoS One Date: 2014-04-18 Impact factor: 3.240
Authors: Mohammad Shohel; Mohammad Mahfuzur Rahman; Asif Zaman; Mir Muhammad Nasir Uddin; Md Mamun Al-Amin; Hasan Mahmud Reza Journal: BMC Womens Health Date: 2014-04-04 Impact factor: 2.809