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Abstract
The effect of deliberate omission of a phased formulation pill, TrinordiolR (ethinyl estradiol 30 μg + levonorgestrel 50μg: 6 tablets; ethinyl estradiol 40 μg + levonorgestrel 75 μg : 5 tablets; ethinyl estradiol 30 μg + levonorgestrel 125 μg: 10 tablets) or a low-dose, combined, oral contraceptive pill, MicrogynonR (ethinyl estradiol 30 μg + levonorgestrel 150 μg: 21 tablets) on the hypothalamo-pituitary-ovarian axis were studied.
Thirty-six women were recruited to the study and divided equally between the two types
of pill. Medication was begun on the 8th pill-free day of the cycle and continued
for 7 days (Group 1), 14 days (Group 2) or 21 days (Group 3). Levels of FSH, LH, estradiol
(E2) and progesterone (P) were measured in plasma on alternate days during the final
week of pill therapy, and daily for the 7 days after stopping the pill.
For the first 2 weeks of pill therapy, follicular activity, as judged by plasma levels
of E2, was greater in women taking Trinordiol than in those taking Microgynon, but was
similar in both groups by the third week of pill treatment. Five women taking Trinordiol
(2 in Group 1 and 3 in Group 2) had plasma levels of E2 in excess of 500 pmol/1 whilst taking the pills, but this level of follicular activity
was maintained in only three of these women in the seven ‘pill-free’ days. None of
the women taking Microgynon had levels of E2 above 500 pmol/1 whilst taking the pills and only 1 patient achieved this degree
of follicular activity after stopping the tablets.
One woman who had taken 7 days of Trinordiol (Group 1) showed a rise of plasma levels
of P to 6.8 nmol/1, but luteinization did not occur in any of the remaining 35 women
who took Trinordiol or Microgynon.
These findings suggest that follicular activity is less completely suppressed by Trinordiol
than Microgynon, at least in the first 2 weeks of pill therapy, but that normal ovulation
is still a rare event in the week after cessation of either of these pills, even if
only 7 days of medication have been taken.
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References
- Why do inadvertent pregnancies occur in oral contraceptive users.Contraception. 1983; 27: 531-551
- Studies on low dose oral contraceptives, plasma hormone changes in relation to deliberate pill (Microgynon 30) omission.Contraception. 1979; 20: 61-67
- ‘Escape’ ovulation in women due to the missing of low dose combination oral contraceptive pills.Contraception. 1980; 22: 241-245
- Hormonal consequences of ‘missing the pill’.Contraception. 1982; 6: 545-566
- Hormonal consequences of missing the pill during the first two days of three consecutive artificial cycles.Contraception. 1984; 29: 437-446
- Hormonal profile of the cycle in 68 normally menstruating women.Acta Endocr. (Copenh.). 1980; 94: 89-98
- Prolactin, TSH, LH and FSH responses to a combined LHRH/TRH test at different stages of the menstrual cycle.Clin. Endocr. 1974; 3: 427-435
- Comparison of single and repeated applications of a long-acting synthetic analogue of LHRH [D-SER(TBU)6 EA10LHRH] in the assessment of pituitary gonadotrophin secretory capacity.Clin. Endocr. 1980; 13: 51-56
- Failure of positive feedback in normal men and subjects with testicular feminization.Clin. Endocr. 1977; 71: 353-366
- Production of antisera to steroid hormones in sheep.in: Cameron E.H.D. Hillier S.G. Griffiths K. Steroid Immunoassay, Proceedings of the Fifth Tenovus Workshop. Alpha Publishing Co, Cardiff1975: 111-122
- Log normal distribution of gonadotrophins and ovarian steroid values in the normal menstrual cycle.Am. J. Obstet. Gynecol. 1975; 121: 688-703
- Plasma steroid and gonadotrophin profiles in ovulatory but infertile women.Clin. Endocr. 1978; 8: 241-255
- “Missed pill” conception: fact or fiction.B.M.J. 1985; 290: 1474-1475
- Plasma gonadotrophin and ovarian steroid concentrations in women with menstrual cycles with a short luteal phase.J. Reprod. Fert. 1985; 75: 363-368
- Dose-dependent inhibition by oral contraceptives of the pituitary to release LH and FSH in response to stimulation with LH-RH.Contraception. 1976; 14: 171-181
- The effect of contraceptive steroids on hypothalamic-pituitary function.Am. J. Obstet. Gynecol. 1977; 128: 60-70
- Pulsatile secretion of LH, FSH, prolactin, oestradiol and progesterone during the human menstrual cycle.Clin. Endocr. 1982; 17: 29-42
- Suppression of oestradiol secretion and luteinizing hormone release during oestrogen-progestogen oral contraception therapy.Lancet. 1970; 1: 271-274
- Identification of proteins in pooled human follicular fluid which suppress follicular response to gonadotrophins.J. Clin. Endocr. Metab. 1983; 56: 35-41
- Effect of enucleation of the corpus luteum at different stages of the luteal phase of the human menstrual cycle on subsequent follicular development.J. Reprod. Fert. 1984; 70: 615-624
- Increase in ovulation rate after treatment of ewes with bovine follicular fluid in the luteal phase of the oestrous cycle.J. Reprod. Fert. 1985; 73: 505-515
- Inhibition and subsequent rebound of FSH secretion following treatment with bovine follicular fluid in the ewe.Theriogenology. 1982; 18: 45-53
- Time course of serum FSH suppression in ovariectomized rats injected with porcine follicular fluid (Folliculostatin): effect of estradiol treatment.Biol. Reprod. 1979; 20: 1093-1098
- Missed Pills — what advice should we give?.Br J Fam Plan. 1981; 7: 41-44
Article info
Publication history
Accepted:
November 5,
1986
Received:
September 8,
1986
Identification
Copyright
© 1986 Published by Elsevier Inc.