Contraceptive efficacy of emergency contraception with levonorgestrel given before or after ovulation

Noé, Gabriela; Croxatto, Horacio B.; Salvatierra, Ana María; Reyes, Verónica; Villarroel, Claudio; Muñoz, Carla; Morales, Gabriela; Retamales, Anita

doi:10.1016/j.contraception.2009.12.015

Cited by 54 publications

(15 citation statements)

References 29 publications

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“…In summary, under the conditions studied, LNG caused minimal changes in transcripts levels and, considering their nature and magnitude, it is unlikely they would interfere with endometrial receptivity an assumption confirmed by the studies of Novikova et al (2007) and Noe et al (2010) cited above.…”

Section: Discussionmentioning

confidence: 55%

“…In addition, low doses of mifepristone administered in the luteal phase alter endometrial maturation (Greene et al 1992) and other antiprogestins, such as onapristone produce the same pattern of endometrial alterations (Katkam et al 1995) that will inhibit endometrial receptivity providing a basis of their development for endometrial contraception (Cameron et al 1997) whereas no effects of post-ovulatory LNG administration on the histological features of the endometrium examined during the receptive phase were found (Durand et al 2001, Marions et al 2002. Furthermore, two independent studies have shown that emergency contraception with LNG given before ovulation prevents pregnancy in all treated women and that it fails completely to prevent pregnancy when it is given after ovulation (Novikova et al 2007, Noe et al 2010, confirming the use of LNG as an effective contraceptive method only if it is taken before ovulation. Those two studies provide functional evidence that the few changes in gene expression described here are irrelevant for endometrial receptivity.…”

Section: Discussionmentioning

confidence: 99%

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Effect of single post-ovulatory administration of levonorgestrel on gene expression profile during the receptive period of the human endometrium

Vargas¹,

Tapia-Pizarro²,

Henríquez³

et al. 2011

Journal of Molecular Endocrinology

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The hypothesis that levonorgestrel (LNG) used as an emergency contraceptive interferes with endometrial receptivity remains unproven. We compared the endometrial gene expression profile during the receptive period after administering a single dose of LNG 1 . 5 mg or placebo on day 1 of the luteal phase. An endometrial biopsy was done on day LHC7 or LHC8 and samples were taken from seven volunteers, each one contributing with one cycle treated with placebo and another with LNG. The expression of 20 383 genes was determined using cDNA microarrays. Real-time RT-PCR was used 1) to confirm the differences found in DNA microarray analysis and 2) to determine the effect of LNG on transcript levels of C3, C4BPa, COX2, MAOA, S100A4, and SERPINB9, known to be upregulated during receptivity, and on cPLA2a, JAK1, JNK1, CTSL1, and GSTP1, known to respond to mifepristone. Additional endometrial biopsies were done during the pre-receptive (LHC3) and receptive (LHC7) period and samples were taken from eight untreated volunteers in order to determine the changes associated with acquisition of receptivity of 14 genes. Mean levels of PAEP, TGM2, CLU, IGF2, and IL6ST mRNAs increased after administering LNG while those of HGD, SAT1, EVA1, LOC90133, ANXA1, SLC25A29, CYB5A, CRIP1, and SLC39A14 decreased. Except for the level of ANXA1 transcript, all changes remained within the range observed in untreated controls, and none of the transcripts responding to mifepristone changed in response to LNG. Post-ovulatory administration of LNG caused minimal changes in gene expression profiling during the receptive period. Neither the magnitude nor the nature or direction of the changes endorses the hypothesis that LNG interferes with endometrial receptivity.

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Section: Discussionmentioning

confidence: 55%

Section: Discussionmentioning

confidence: 99%

Effect of single post-ovulatory administration of levonorgestrel on gene expression profile during the receptive period of the human endometrium

Vargas¹,

Tapia-Pizarro²,

Henríquez³

et al. 2011

Journal of Molecular Endocrinology

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“…When taken as instructed, levonorgestrel tablets can reduce the risk of pregnancy by approximately 80% (per “plan B” label, for example) relative to the number of pregnancies that would be expected to occur with unprotected intercourse [16], [25], [26]. This product type is only effective when taken before ovulation [27], [28].…”

Section: Discussionmentioning

confidence: 99%

A Tiered Analytical Approach for Investigating Poor Quality Emergency Contraceptives

Monge¹,

Dwivedi²,

Zhou³

et al. 2014

PLoS ONE

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Reproductive health has been deleteriously affected by poor quality medicines. Emergency contraceptive pills (ECPs) are an important birth control method that women can use after unprotected coitus for reducing the risk of pregnancy. In response to the detection of poor quality ECPs commercially available in the Peruvian market we developed a tiered multi-platform analytical strategy. In a survey to assess ECP medicine quality in Peru, 7 out of 25 different batches showed inadequate release of levonorgestrel by dissolution testing or improper amounts of active ingredient. One batch was found to contain a wrong active ingredient, with no detectable levonorgestrel. By combining ultrahigh performance liquid chromatography-ion mobility spectrometry-mass spectrometry (UHPLC-IMS-MS) and direct analysis in real time MS (DART-MS) the unknown compound was identified as the antibiotic sulfamethoxazole. Quantitation by UHPLC-triple quadrupole tandem MS (QqQ-MS/MS) indicated that the wrong ingredient was present in the ECP sample at levels which could have significant physiological effects. Further chemical characterization of the poor quality ECP samples included the identification of the excipients by 2D Diffusion-Ordered Nuclear Magnetic Resonance Spectroscopy (DOSY 1H NMR) indicating the presence of lactose and magnesium stearate.

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“…6 Therefore, because the risk of pregnancy is highest in the two days leading up to ovulation, ulipristal acetate is probably more effective than levonorgestrel. Levonorgestrel is not effective after fertilisation, 7 and it is unclear whether ulipristal acetate has any effect after ovulation.…”

Section: How Does It Work? Intrauterine Devicementioning

confidence: 99%

Emergency contraception

Prabakar¹,

Webb²

2012

BMJ

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Contraceptive efficacy of emergency contraception with levonorgestrel given before or after ovulation

Abstract: We conclude that LNG-EC prevents pregnancy only when taken before fertilization of the ovum has occurred.

Cited by 54 publications

References 29 publications

Effect of single post-ovulatory administration of levonorgestrel on gene expression profile during the receptive period of the human endometrium

Effect of single post-ovulatory administration of levonorgestrel on gene expression profile during the receptive period of the human endometrium

A Tiered Analytical Approach for Investigating Poor Quality Emergency Contraceptives

Emergency contraception

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