Human Reproduction, Vol. 16, No. 1, 76-81,
January 2001
© 2001 European Society of Human Reproduction and Embryology
Charcoal treatment and risk of escape ovulation in oral contraceptive users
1 The Family Federation of Finland (Väestöliitto), FIN-00101 Helsinki, 2 Steroid Research Laboratory, Institute of Biomedicine, FIN-00014 University of Helsinki, 3 CRST Biostatistics Unit, FIN-20014 University of Turku, and 4 Leiras Oy, Research & Development, FIN-20101 Turku, Finland
Ovulatory potential was studied during the use of two oral contraceptive pill preparations, after repeated mid-cycle administration of activated charcoal. Eleven women used monophasic pills containing gestodene, 75 µg, plus ethinyl oestradiol, 30 µg, or norethisterone acetate, 1 mg, plus ethinyl oestradiol, 30 µg, for 4 months each, in randomized order. During both pill treatments the third cycle was a control cycle, and during the fourth cycle of both pill types, 5 g of activated charcoal was ingested four times a day, starting 3 h after pill intake, on cycle days 12, 13 and 14. Ovarian activity was monitored by intravaginal ultrasonography of follicles and by measurements of serum concentrations of LH, FSH, oestradiol and progesterone throughout the control and charcoal-treatment cycles of both pill treatments. None of the women ovulated. Follicular activity seen in two women did not correlate with charcoal administration. It is concluded that the possible enterohepatic recirculation of gestodene and norethisterone is not of clinical importance. Repeated charcoal treatment, when administered 3 h after but at least 12 h before pill intake, can be used to treat diarrhoea in women taking oral contraceptives.
Key words: activated charcoal/combined oral contraceptive/enterohepatic circulation/progestogens/risk of ovulation
5 To whom correspondence should be addressed at: Leiras Oy, Clinical Research, Research & Development, Pasilanraitio 9,PO Box 325, FIN-00101 Helsinki, Finland. E-mail: kaisa.elomaa{at}leiras.fi