Related Experiment Video
Updated: Jul 27, 2026

Surgical Techniques to Optimize Ovarian Reserve during Laparoscopic Cystectomy for Ovarian Endometrioma
Published on: January 22, 2022
Timing of onset of contraceptive effectiveness in Depo-Provera users. II. Effects on ovarian function
C A Petta1, A Faúndes, T R Dunson
1Departamento de Tocoginecologia, Universidade Estadual de Campinas, Brazil. gpetta@turing.unicamp.br
Objective:
To determine the timing of onset of contraceptive effectiveness after the first injection of 150 mg of depot medroxyprogesterone acetate (DMPA) administered between days 8 and 13 of the menstrual cycle.
Design:
Descriptive, prospective study.
Setting:
A tertiary university referral center.
Patient(S):
Thirty healthy women between 18 and 40 years of age.
Intervention:
Volunteers were injected with DMPA between days 8 and 13 (5 women on each day) of the menstrual cycle.
Main Outcome Measure(S):
Ovarian function determined by serum levels of E2 and progesterone and follicular development evaluated by vaginal ultrasound.
Result(S):
In nine (30%) of 30 women studied, DMPA did not prevent ovulation. All ovulations occurred in women receiving DMPA between days 10 and 13 of the cycle. No woman who received injections on day 8 or 9 ovulated. Ovulation suppression was more effective in women with low ovarian activity. All ovulation occurred within 3 days after the injection.
Conclusion:
A back-up contraceptive method, used after the 7th day of the menstrual cycle, is recommended for up to 7 days after the first injection of DMPA.
Related Concept Videos
Hormonal Regulation of the Menstrual Cycle
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH release.
Ovarian Cycle
Hormonal Control of the Ovarian Cycle
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...
Menopause
Birth Control Methods
Intrauterine Drug Delivery Systems

