Studies on Low-Dose Oral Contraceptives: Cervical Mucus and Plasma Hormone Changes in Relation to Circulating D-Norgestrel and 17α-Ethynyl Estradiol Concentrations

Length of the menstrual cycle after discontinuation of oral contraceptives

“…Elstein and colleagues [10] performed a study in three women who discontinued the use of an OC containing 30 mg EE and 150 mg Dnorgestrel. Ovulation occurred within 20 days after cessation of the OC.…”

“…In the past a few studies were done to investigate the cycle length after discontinuation of high-dose combination OCs [3][4][5][6], most of them reporting an increased duration of the first post-pill cycle. In more recent studies with lower-dose OCs a rapid return of ovulation after cessation of OC intake was reported, but data on the day of ovulation or the next menstruation were not given [7][8][9] or only the duration until the first ovulation was investigated [10,11]. Recently, a large prospective study reported the characteristics of multiple cycles after discontinuation of OCs in 175 women, in comparison with a control group of 284 non-OC users [12].…”

Changes in ovine cervical mucus in response to oestrogen treatment

“…The physical nature of the cervical mucus varies greatly throughout the oestrous or menstrual cycle and plays a vital role in these functions (Mattner, 1969; Davajan, Nakamura & Kharma, 1970). An alteration of the physical properties of mucus by concurrent progestagen treatment of women (Elstein et al, 1976) or after prolonged exposure of ewes to oestrogenic pasture (Adams, 1976) leads to interference with sperm transport and reduces the likelihood of fertilization. The physical properties of mucus are also believed to be responsible for its ability to maintain the viability of spermatozoa in vitro (Mattner, 1969).…”

A Radioimmunoassay for Ethinyl Oestradiol in Plasma Incorporating an Immunosorbent, Pre-assay Purification Procedure

“…in subjects taking 30 and 50 fLg of EE 2 alone; using the same antiserum and tracer as Lahteenrnaki and Nilsson they reported concentrations of 170-340 and 320-456 pmol/l. It is possible that higher concentrations of apparent EE 2 seen in subjects receiving 12 concomitant progestagens represent EE 2 and the corresponding IS-methyl EE 2 formed from norethisterone and norgestrel respectively. However the conversion of norethisterone and norgestrel to phenolic steroids in significant amounts remains controversial, and the topic is reviewed elsewhere.P The immunosorbent extraction procedure described here relies on a non-specific anti-oestrogen serum, raised against 17~-oestradiol 17-hemisuccinate conjugate, which shows high affinity binding for ethinyl oestradiol but not for norethisterone.…”