A comparative study on the return to ovulation following chronic use of once-a-month injectable contraceptives

• Published in: Contraception (Stoneham) 1995-05, Vol.51 (5), p.307-311
• Main Authors: Bassol, Susana, Hernandez, Cecilia, Nava, Martha P., Trujillo, Ana Ma, de la Cruz, Dora Luz
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Birth control; Contraceptives, Oral, Combined - administration & dosage; Contraceptives, Oral, Combined - adverse effects; Contraceptives, Oral, Combined - pharmacokinetics; Cyclofem; Drug Combinations; endometrial bleeding patterns; Estradiol - administration & dosage; Estradiol - adverse effects; Estradiol - analogs & derivatives; Estradiol - pharmacokinetics; Estrone - urine; Female; Glucuronates - urine; Gynecology. Andrology. Obstetrics; Humans; hypothalamus-pituitary-ovarian axis; Injections, Intramuscular; Kinetics; Medical sciences; Medroxyprogesterone Acetate - administration & dosage; Medroxyprogesterone Acetate - adverse effects; Medroxyprogesterone Acetate - pharmacokinetics; menses; Mesigyna; Mexico; Norethindrone - administration & dosage; Norethindrone - adverse effects; Norethindrone - analogs & derivatives; Norethindrone - pharmacokinetics; oestrone glucuronide; once-a-month injectable contraceptive; Other methods of contraception. Sterilization; ovulation; Ovulation - physiology; Pregnanediol - urine; pregnanediol glucuronide; return to ovulation
• ISSN: 0010-7824; 1879-0518
• DOI: 10.1016/0010-7824(95)00080-T

A comparative study was undertaken involving 21 Mexican women who discontinued the use of medroxyprogesterone acetate 25 mg plus oestradiol cypionate 5 mg (Cyclofem) and norethisterone enanthate 50 mg plus oestradiol valerate 5 mg (Mesigyna) to assess the time required for the return to menses and ovulation. All subjects were exposed to once-a-month injectable contraceptives for two years and were followed for 120 days after the last injection. The urinary concentration of oestrone glucuronide and pregnanediol glucuronide was determined daily in all subjects beginning one month after the last injection. The results disclosed that ovulatory cycles were documented after 120 days of the last injection in six women of each studied group. Similar endometrial bleeding patterns were observed in both groups, indicating that the two drugs have alike pharmacokinetic and pharmacodynamic effects.