Emergency contraception: clinical outcomes

The Levonorgestrel-Releasing Intrauterine Device as Emergency Contraception: Re-examining the Data

Emergency contraception methods that also deliver ongoing contraception provide the most effective options for individuals hoping to prevent pregnancy after unprotected intercourse. Although the copper intrauterine device (IUD) provides the most effective option for emergency contraception because the device prevents pregnancy when placed before implantation and offers long-acting contraception, uptake by patients has been limited. Recently, the Society of Family Planning issued new guidance recommending the levonorgestrel IUD (LNG-IUD) as an emergency contraception option along with the copper IUD. Here, we review evidence related to this recommendation and conclude that the available data do not support use of the LNG-IUD for emergency contraception. We discuss the mechanisms of action of emergency contraception methods and how these concepts interface with the current political and social landscape of contraception and abortion care. We describe limitations of the existing evidence supporting use of the LNG-IUD as emergency contraception and highlight the critical research needed to establish the device as a highly effective method of emergency contraception.

Preliminary report of sexual assaults at Ekiti Sexual Assault Referral Centre, Ado-Ekiti, Southwest, Nigeria (Moremi Clinic)

There has been a surge in the incidence and severity of sexual assaults globally with the insurgence of COVID-19 owing to lockdown restrictions. Ekiti Sexual Assault Referral Centre, Ado-Ekiti also known as Moremi Clinic was established in June 2020 as a multisectoral response centre to this surge. Seventy-four survivors accessed medical services from June 2020 to May 2021. Adolescents made up 54.1% while the median age was 14.5 years. Only seven survivors were seen within 24 h of the event and around a quarter had follow-up visits. A quarter of survivors reported repeat episodes of sexual assault. Complications documented were sexually transmitted infections (13.5%), depression (4.1%) and posttraumatic stress disorder (5.4%). There was a failure of contraception in 4.5% of survivors who had taken emergency contraceptive pills. For improvements in quality of care, strategies to ensure early presentation and encourage follow-up visits must be introduced.

Birth control knowledge among freshmen of four Italian universities

Since sexual health education (SHE) is not mandatory in Italian schools, we conducted a survey on freshmen of four Italian university campuses in 2012 to investigate the respective level of sexual health knowledge (SHK) in relation to birth control, with the aim to inform public health policy makers. A convenience strategy was employed to sample 4,552 freshmen registered with various undergraduate courses at four Italian universities: Padua university (Veneto Region); university of Milan (Lombardy Region); university of Bergamo (Lombardy Region); university of Palermo (Sicily Region). We investigated the level of SHK on birth control using 6 proxy indicators: (1) the average length of a woman’s period [outcome with 3 levels: wrong (base) vs. acceptable vs. correct]; (2) the most fertile interval within a woman’s period (binary outcome: correct vs. wrong answer); (3) the event between the end of a period and the beginning of the next cycle (binary outcome: correct vs. wrong answer); (4) the average survival of spermatozoa in the womb (binary outcome: correct vs. wrong answer); (5) the concept of contraception (binary outcome: correct vs. wrong answer); (6) the efficacy of various contraceptives to prevent unintended pregnancies (linear score: 0–17). We fitted 6 separate models of multiple regression: multinomial for outcome 1; logistic for outcomes 2, 3, 4, 6; linear for outcome 6. Statistical estimates were adjusted for a number of socio-demographic factors. Results were expressed as odds ratios (OR) for the 4 multiple logistic regression models, linear coefficients (RC) for the linear regression model and relative risk ratio (RRR) for the multinomial logistic regression model. The level of significance of each risk estimate was set at 0.05. The level of SHK of freshmen sampled was rather low, as 60% interviewees did not know the average length of a woman’s period, the average survival of spermatozoa in the womb and the concept of contraception, whilst the most fertile interval within a woman’s period was known only to 55% of interviewees. The mean score of SHK on the efficacy of various contraceptive methods was only 5 (scale 0–17). Some categories of students were consistently and significantly less knowledgeable on birth control at multivariable analysis: males; students from the university of Palermo; those with vocational secondary school education and those not in a romantic relationship at the time the survey was conducted. The results of this survey clearly call for the introduction of SHE programs in Italian schools, as already done in several European countries. School SHE should start as early as possible, ideally even before secondary school. SHE should be holistic and delivered with a multiple agency coordinated approach involving the Ministry of Health, the Ministry of Education, University and Scientific Research (MIUR), families, schools, public health departments, primary health care providers, pharmacists, media, other.

N-glycosylation of uterine endometrium determines its receptivity

Glycosylation alters the molecular and functional features of glycoproteins, which is closely related with many physiological processes and diseases. During "window of implantation", uterine endometrium transforms into a receptive status to accept the embryo, thereby establishing successful embryo implantation. In this article, we aimed at investigating the role of N-glycosylation, a major modification type of glycoproteins, in the process of endometrial receptivity establishment. Results found that human uterine endometrial tissues at mid-secretory phase exhibited Lectin PHA-E+L (recognizes the branched N-glycans) positive N-glycans as measured by the Lectin fluorescent staining analysis. By utilizing in vitro implantation model, we found that de-N-glycosylation of human endometrial Ishikawa and RL95-2 cells by tunicamycin (inhibitor of N-glycosylation) and peptide-N-glycosidase F (PNGase F) impaired their receptive ability to human trophoblastic JAR cells. Meanwhile, N-glycosylation of integrin αvβ3 and leukemia inhibitory factor receptor (LIFR) are found to play key roles in regulating the ECM-dependent FAK/Paxillin and LIF-induced STAT3 signaling pathways, respectively, thus affecting the receptive potentials of endometrial cells. Furthermore, in vivo experiments and primary mouse endometrial cells-embryos coculture model further verified that N-glycosylation of mouse endometrial cells contributed to the successful implantation. Our results provide new evidence to show that N-glycosylation of uterine endometrium is essential for maintaining the receptive functions, which gives a better understanding of the glycobiology of implantation.

Prevention of unintended pregnancies by using emergency contraception: the differences between levonorgestrel and ulipristal acetate. A theoretical model using data from a survey on the use of emergency contraception in Spain, 2017

Objective: To estimate the differences in unintended pregnancies avoided using either levonorgestrel (LNG) or ulipristal acetate (UPA) emergency contraception (EC). Design: Cross-sectional study. Setting: Survey carried out in Spain. Participants: 1000 Spanish women reporting unprotected sex in 2017. Main measurements: EC use, reasons for not using EC, calculation of the number of unintended pregnancies avoided. Results: 39% of Spanish women having had unprotected sex used EC. 61% of those women did not use EC and 11% did not know the existence of this resource. In 2017 the use of EC prevented 101,271 unintended pregnancies. If instead of using LNG every woman had used UPA another 15,979 additional pregnancies could have been prevented. Conclusions: If all Spanish women having unprotected sex used EC we could expect a significant decrease in the number of unintended pregnancies and abortions. Using UPA instead of LNG would have a greater impact on that reduction with the corresponding benefit for women and society as a whole.

Levonorgestrel only emergency contraceptive use and risk of ectopic pregnancy in Eldoret Kenya: a case-control study

INTRODUCTION

ectopic pregnancy is one of the causes of maternal morbidity and mortality in sub-Saharan Africa. Levonorgestrel (LNG) only emergency contraceptive pill is a well-established emergency contraceptive pill that is administered within 72 hours after unprotected intercourse. This study aimed at determining whether or not there is a significant association between levonorgestrel emergency contraceptive use and the occurrence of ectopic pregnancy.

METHODS

case-control (1:3) study among 79 women with ectopic pregnancy (cases) matched against 237 women without (controls) at Moi Teaching and Referral Hospital in Eldoret, Kenya; Sociodemographic and clinical data were collected using a questionnaire. Association between ectopic pregnancy and LNG-EC was assessed using Pearson chi-square test. The relationship between outcome and exposure (while adjusting for confounders) was assessed using logistic regression model.

RESULTS

The mean age was 27.15 years. Both cases and controls were similar by age (p = 0.990), educational level (p = 0.850), marital status (p = 0.559), employment status (p = 0.186) and parity (p = 0.999). Seventy-eight (24.7%) participants had a history of miscarriage. A higher proportion of the cases had history of using LNG-EC compared to the controls (32.9% vs. 7.2%, p < 0.001). The use of LNG-EC portended more than nine times increased odds of ectopic pregnancy compared to other contraceptive methods {OR = 9.34 (95% CI: 3.9 - 16.0)}.

CONCLUSION

levonorgestrel only emergency contraceptive use was associated with ectopic pregnancy. One of the limitations of this study is that we could not control for all confounders of ectopic pregnancy.

Methods of contraception: the nurse's role in providing care and advice

Most women require contraception during their reproductive years, and many methods are available. Women should have access to all of these methods and be encouraged to take an active role in decision-making about their choice of contraceptive, within medical eligibility constraints. Long-acting reversible contraceptives are more effective than user-dependent methods, such as condoms, and should be offered to all women during contraceptive consultations. In primary care settings, nurses often provide much basic contraception care and advice. Nurses should ensure that they work within the limits of their competence and are aware of how and where to refer women for specialist support, if required.

Knowledge of and Interest in the Copper Intrauterine Device Among Women Seeking Emergency Contraception

OBJECTIVE

Emergency contraception (EC) includes hormonal pills (levonorgestrel or ulipristal acetate) and the copper IUD (Cu-IUD). The Cu-IUD is more effective for EC than hormonal pills but remains underused, possibly because of lack of knowledge or interest. The objective of this study was to examine knowledge of and interest in the Cu-IUD for EC among Canadian women seeking EC.

METHODS

The study used a cross-sectional convenience survey of English-speaking women presenting for EC at two sexual health clinics in Toronto. The anonymous paper-based survey was completed in the waiting room. The main outcome measures were women's knowledge of and interest in the Cu-IUD for EC. Demographic and reproductive health data were also collected.

RESULTS

Between January and December 2013, 124 surveys were completed. Mean age of respondents was 26 years (SD ± 6.9). Most were single (85%), and over one half had completed postsecondary education. Overall, 77% had heard of the Cu-IUD, but only 21% were aware of its use for EC. Over 50% were aware that the Cu-IUD is hormone-free and may be used for long-term contraception. Women were less familiar with the window of administration of the Cu-IUD for EC (26%) and its efficacy (6%). In total, 23% (28 of 124) of women were interested in the Cu-IUD, including eight women scheduled to receive one that day.

CONCLUSION

Women presenting for EC were unaware of the Cu-IUD but were moderately interested in it once informed. Public education and routine counselling about the Cu-IUD at EC visits may increase the uptake of this method.

Emergency Contraception Algorithm and Guide for Clinicians

There are currently three forms of emergency contraception: oral levonorgestrel, oral ulipristal acetate, and the copper intrauterine device. The copper intrauterine device is the most effective, followed by ulipristal acetate and levonorgestrel, respectively. Although levonorgestrel is the least effective method, studies show that more prescribers are familiar with it and that is the most frequently used method. Clinicians should consider several factors when helping women make informed medical decisions regarding emergency contraception, including access to the products, a woman's individual preference, timing since unprotected intercourse, body mass index or weight, and initiation or resumption of routine contraception. This article explains and summarizes these considerations and provides an algorithm to guide clinicians.

Unplanned pregnancy-risks and use of emergency contraception: a survey of two Nigerian Universities

BACKGROUND

The vulnerabilities of young women of low socio-economic status and those with little or no formal education tend to dominate the discourse on unplanned pregnancy, unsafe abortion and emergency contraception (EC) in sub-Saharan Africa. This article draws on a survey conducted among female undergraduate students to shed light on sexual behaviour and the dynamics of emergency contraceptive use among this cohort.

METHODS

The survey involved 420 female undergraduate students drawn using a multistage sampling technique, while a self-administered questionnaire was used for data collection. Univariate and bivariate analyses were applied to examine the factors associated with the use of emergency contraception.

RESULTS

Of the 176 female students who reported being sexually active in the year preceding the survey, only 38.6% reported the use of condom during the entire year. Of those who reported unplanned pregnancy anxiety n = 94, about 30.1% used EC, 20.4% used non-EC pills as EC, while others reported having used no EC. A few respondents (n = 3) had terminated a pregnancy under unsafe conditions. Awareness of EC (p < 0.001), knowledge of timing of EC (p = 0.001), perceived risk of unplanned pregnancy (p < 0.001), and level of study (p = 0.013), were significantly correlated with the use of EC.

CONCLUSION

The study revealed that educated youths engaged in high-risk sexual activities and also, sought recourse to unproven and unsafe contraceptive methods. Poor knowledge of EC methods and timing of use, as well as wrong perception about EC side effects, are barriers to the utilisation of EC for the prevention of unplanned pregnancy among the study participants.

Novel contraceptive targets to inhibit ovulation: the prostaglandin E2 pathway

BACKGROUND

Prostaglandin E2 (PGE2) is an essential intrafollicular regulator of ovulation. In contrast with the one-gene, one-protein concept for synthesis of peptide signaling molecules, production and metabolism of bioactive PGE2 requires controlled expression of many proteins, correct subcellular localization of enzymes, coordinated PGE2 synthesis and metabolism, and prostaglandin transport in and out of cells to facilitate PGE2 action and degradation. Elevated intrafollicular PGE2 is required for successful ovulation, so disruption of PGE2 synthesis, metabolism or transport may yield effective contraceptive strategies.

METHODS

This review summarizes case reports and studies on ovulation inhibition in women and macaques treated with cyclooxygenase inhibitors published from 1987 to 2014. These findings are discussed in the context of studies describing levels of mRNA, protein, and activity of prostaglandin synthesis and metabolic enzymes as well as prostaglandin transporters in ovarian cells.

RESULTS

The ovulatory surge of LH regulates the expression of each component of the PGE2 synthesis-metabolism-transport pathway within the ovulatory follicle. Data from primary ovarian cells and cancer cell lines suggest that enzymes and transporters can cooperate to optimize bioactive PGE2 levels. Elevated intrafollicular PGE2 mediates key ovulatory events including cumulus expansion, follicle rupture and oocyte release. Inhibitors of the prostaglandin-endoperoxide synthase 2 (PTGS2) enzyme (also known as cyclooxygenase-2 or COX2) reduce ovulation rates in women. Studies in macaques show that PTGS2 inhibitors can reduce the rates of cumulus expansion, oocyte release, follicle rupture, oocyte nuclear maturation and fertilization. A PTGS2 inhibitor reduced pregnancy rates in breeding macaques when administered to simulate emergency contraception. However, PTGS2 inhibition did not prevent pregnancy in monkeys when administered to simulate monthly contraceptive use.

CONCLUSION

PTGS2 inhibitors alone may be suitable for use as emergency contraceptives. However, drugs of this class are unlikely to be effective as monthly contraceptives. Inhibitors of additional PGE2 synthesis enzymes or modulation of PGE2 metabolism or transport also hold potential for reducing follicular PGE2 and preventing ovulation. Approaches which target multiple components of the PGE2 synthesis-metabolism-transport pathway may be required to effectively block ovulation and lead to the development of novel contraceptive options for women. Therapies which target PGE2 may also impact disorders of the uterus and could also have benefits for women's health in addition to contraception.

Preferential Cyclooxygenase 2 Inhibitors as a Nonhormonal Method of Emergency Contraception: A Look at the Evidence

OBJECTIVE

To review the literature surrounding the use of preferential cyclooxygenase 2 (COX-2) inhibitors as an alternative form of emergency contraception.

DATA SOURCES

MEDLINE (1950 to February 2014) was searched using the key words cyclooxygenase or COX-2 combined with contraception, emergency contraception, or ovulation. Results were limited to randomized control trials, controlled clinical trials, and clinical trials.

STUDY SELECTION AND DATA EXTRACTION

Human trials that measured the effects of COX inhibition on female reproductive potential were included for review.

DATA SYNTHESIS

The effects of the COX-2 inhibitors rofecoxib, celecoxib, and meloxicam were evaluated in 6 trials. Each of which was small in scope, enrolled women of variable fertility status, used different dosing regimens, included multiple end points, and had variable results.

CONCLUSIONS

Insufficient evidence exists to fully support the use of preferential COX-2 inhibitors as a form of emergency contraception. Although all trials resulted in a decrease in ovulatory cycles, outcomes varied between dosing strategies and agents used. A lack of homogeneity in these studies makes comparisons difficult. However, success of meloxicam in multiple trials warrants further study. Larger human trials are necessary before the clinical utility of this method of emergency contraception can be fully appreciated.

Physical and mental development of children after levonorgestrel emergency contraception exposure: a follow-up prospective cohort study

Levonorgestrel (LNG), a dedicated emergency contraception (EC) product, has been available over-the-counter in China for more than 14 yr. Although LNG-EC is considered to have no effects on the developing fetus if the contraceptive fails and pregnancy occurs, there have been a few studies specifically examining this issue. The purpose of this study was to compare the physical and mental development of children born after LNG-EC failure with that of a cohort of children born to mothers with no history of exposure to LNG or any teratogenic substances. A group of 195 children who were exposed to LNG-EC during their mothers' conception cycle (study group) were matched to a group of 214 children without exposure to LNG (control group). The physical and mental development of the children were evaluated and compared over a 2-yr period. There were four congenital malformations in the study group and three in the control group (2.1% vs. 1.4%, respectively, P > 0.05). Over the 2-yr follow-up period, there were no statistically significant differences between the two groups with respect to children's weight, height, head circumference, and intelligence scores, and the values of all parameters of both groups were similar to those of the national standards. In summary, LNG-EC has no effect on the physical growth, mental development, or occurrence of birth defects in children born from pregnancies in which EC failed.

Effect of changes to cost and availability of emergency contraception on users' profiles in an emergency department in Catalunya

OBJECTIVE

Emergency contraception (EC) accessibility has evolved differently in Catalunya as compared with other autonomous communities in Spain. Free-of-charge access within the Public Health System was authorised in 2004, and over-the-counter (OTC) access was implemented in 2009. The aim of the study is to assess the impact of these measures on demand and users' profiles at our institution.

METHODS

A retrospective study, in our Emergency Department, was conducted to evaluate EC requests in relationship to accessibility modifications. The age of women and which days of the week they attended were analysed.

RESULTS

The number of EC requests, the distribution by age and the demand over the week remained stable after access to EC became free of charge. However, requests sharply decreased following OTC access implementation. Distribution by age also changed, with a significant increase in requests from women under 25 years (72% vs 56%, p < 0.001). Demand was greatest on Sunday and Monday, and this distribution persisted over the study period.

CONCLUSION

EC requests remained unchanged following free-of-charge access to EC, but decreased after OTC implementation. Women currently seeking EC at no cost at our institution are more likely to be younger and to request it on a Monday.

Use of ulipristal acetate and levonorgestrel for emergency contraception: a follow-up study

OBJECTIVES

Previously we showed that increasing the choice of emergency contraception (EC) guided by medical eligibility did not result in wholesale large-scale usage of ulipristal acetate (UPA). This further 12-month study aimed to answer three questions. (1) Does offering choice of EC lead to change in methods used? (2) Are women who choose UPA more likely than those who choose levonorgestrel (LNG) to continue using condoms for subsequent contraception or to decline any ongoing contraception? (3) Do more women choosing LNG 'quick start' hormonal contraception?

METHODS

A retrospective study of EC episodes (1 April 2012 to 31 March 2013) by quarters. Among women offered all three methods of EC (49.1%) we noted the method chosen, and decisions on ongoing contraception among those choosing either LNG or UPA. Differences were tested for statistical significance.

RESULTS

In 6110 episodes of EC, LNG was issued in 69.2%, UPA in 26.0%, and a copper intrauterine device (Cu-IUD) was fitted in 4.8%. Quarter by quarter, the data show a small decline in LNG use, suggesting plateauing by the last quarter, and a significant increase in UPA use between the first and the other three quarters (p<0.001). Use of the Cu-IUD remained static. The percentage of women offered three methods rose to 54.2%. In women offered full choice (3000; 49.1%) we saw a significant increase in choice of UPA, from 39.3% to 48.6% (p<0.001). Women who chose LNG were more likely to quick start (p=0.02) or be continuing contraception already used (p<0.001). Overall, those choosing UPA were more likely to use condoms (p<0.001) but were no more likely to decline ongoing contraception (p=0.13).

CONCLUSIONS

There was a significant increase in women using UPA for EC compared with our previous study, particularly among those wishing to use condoms for continuing contraception. Women choosing LNG were more likely to quick start pills or to continue current hormonal contraception. Detailed attention to continuing contraception following EC may be an important factor in the prevention of unwanted pregnancy.

Family planning: choices and challenges for developing countries

While slow and uneven progress has been made on maternal health, attaining the 1994 Cairo International Conference on Population and Development (ICPD) goal for achieving universal access to reproductive health remains elusive for many developing countries. Assuring access to sexual and reproductive health services, including integrated family planning services, remains a critical strategy for improving the health and well-being of women and alleviating poverty. Family planning not only prevents maternal, infant, and child deaths, but also empowers women to engage fully in socioeconomic development and provides them with reproductive choices. This paper will discuss the current landscape of contraception in developing countries, including options available to women and couples, as well as the challenges to its provision. Finally, we review suggestions to improve access and promising strategies to ensure all people have universal access to reproductive health options.

Selective progesterone receptor modulators: an update

INTRODUCTION

Several selective progesterone receptor modulators (SPRMs) show promise in several areas of medicine and this work has been summarized by us in 2008.

AREAS COVERED

Since the publication of our reviews, several developments have taken place in the field of reproductive medicine. The first is emergency contraception (EC). Two SPRMs are clinically utilized today: mifepristone (MFP) and ulipristal acetate (UPA). MFP is available for EC in up to 120 h following unprotected intercourse. A dose of 10 mg is significantly more effective than levonorgestrel (LNG). In a metanalysis of the use of UPA versus LNG up to 72 h after unprotected intercourse, failure rates of 1.4 versus 2.2% were reported. The second is contraception. A daily dose of 2 mg MFP can block ovulation and several MFP regimens are being tested, including a vaginal ring releasing MFP. The third is the preoperative administration in women harboring leiomyomas, where clinical testing of several SPRM has shown that they can decrease uterine leiomyomas' size and substantially reduce uterine bleeding. SPRM can induce unusual, specific endometrial appearances. Many believe that these changes should not cause concern, but the issue remains controversial.

EXPERT OPINION

SPRMs are very effective in EC and for the preoperative treatment of uterine leiomyomas.

Can we reduce costs and prevent more unintended pregnancies? A cost of illness and cost-effectiveness study comparing two methods of EHC

OBJECTIVES

To calculate the cost of an unintended pregnancy in 2011 and use this cost in a cost-effectiveness model comparing ulipristal acetate (UPA) with levonorgestrel (LNG) for emergency hormonal contraception (EHC).

DESIGN

Retrospective analysis of published data sources and published cost-effectiveness model.

SETTING

Women presenting in primary care in England for EHC within 24 or 72 h of unprotected sexual intercourse (UPSI).

INTERVENTIONS

EHC of either LNG (1.5 mg) or UPA (30 mg).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure is the number and direct and indirect costs of an unintended pregnancy. The secondary outcome measure is the consequence of unintended pregnancy: miscarriage, abortion, ectopic pregnancy, stillbirth or live birth.

RESULTS

From the comparative clinical studies of EHC we observe that if 125 women receive either LNG or UPA within 72 h of UPSI, there will be one less pregnancy due to method failure in the UPA group than in the LNG group. We calculate the cost of an unintended pregnancy to be £1663 in direct healthcare costs rising to £2922 with the inclusion of social costs. Using these costs in the comparative cost-effectiveness model shows that it costs £194 less in direct health costs alone to prevent one more pregnancy with UPA than with LNG. The inclusion of social costs of pregnancy increases this cost-saving potential to £1453 for each extra pregnancy avoided with UPA compared with LNG.

CONCLUSIONS

Clinical trials have demonstrated the superior efficacy of UPA compared with LNG as a method of EHC. Given that it costs less overall in health and social costs of pregnancy while preventing more pregnancies, UPA is said to be the dominant treatment, and primary care services should shift to offering UPA as the preferred oral option to women presenting within 24 and 72 h of UPSI.

The COX-2 inhibitor meloxicam prevents pregnancy when administered as an emergency contraceptive to nonhuman primates

OBJECTIVE

Cyclooxygenase-2 (COX-2) inhibitors reduce prostaglandin synthesis and disrupt essential reproductive processes. Ultrasound studies in women demonstrated that oral COX-2 inhibitors can delay or prevent follicle collapse associated with ovulation. The goal of this study was to determine if oral administration of a COX-2 inhibitor can inhibit reproductive function with sufficient efficacy to prevent pregnancy in primates.

STUDY DESIGN

The COX-2 inhibitor meloxicam (or vehicle) was administered orally to proven fertile female cynomolgus macaques using one emergency contraceptive model and three monthly contraceptive models. In the emergency contraceptive model, females were bred with a proven fertile male once 2±1 days before ovulation, returned to the females' home cage, and then received 5 days of meloxicam treatment. In the monthly contraceptive models, females were co-caged for breeding with a proven fertile male for a total of 5 days beginning 2±1 days before ovulation. Animals received meloxicam treatment (1) cycle days 5-22, or (2) every day, or (3) each day of the 5-day breeding period. Female were then assessed for pregnancy.

RESULTS

The pregnancy rate with meloxicam administration using the emergency contraception model was 6.5%, significantly lower than the pregnancy rate of 33.3% when vehicle without meloxicam was administered. Pregnancy rates with the three monthly contraceptive models (75%-100%) were not consistent with preventing pregnancy.

CONCLUSIONS

Oral COX-2 inhibitor administration can prevent pregnancy after a single instance of breeding in primates. While meloxicam may be ineffective for regular contraception, pharmacological inhibition of COX-2 may be an effective method of emergency contraception for women.

IMPLICATIONS

COX-2 inhibitors can interfere with ovulation, but the contraceptive efficacy of drugs of this class has not been directly tested. This study, conducted in nonhuman primates, is the first to suggest that a COX-2 inhibitor may be effective as an emergency contraceptive.

Obesity and hormonal contraceptive efficacy

Obesity is a major public health concern affecting an increasing proportion of reproductive-aged women. Avoiding unintended pregnancy is of major importance, given the increased risks associated with pregnancy, but obesity may affect the efficacy of hormonal contraceptives by altering how these drugs are absorbed, distributed, metabolized or eliminated. Limited data suggest that long-acting, reversible contraceptives maintain excellent efficacy in obese women. Some studies demonstrating altered pharmacokinetic parameters and increased failure rates with combined oral contraceptives, the contraceptive patch and emergency contraceptive pills suggest decreased efficacy of these methods. It is unclear whether bariatric surgery affects hormonal contraceptive efficacy. Obese women should be offered the full range of contraceptive options, with counseling that balances the risks and benefits of each method, including the risk of unintended pregnancy.