Metabolism of injectable formulations of contraceptive steroids in obese and thin women

Misreporting contraceptive use and the association of peak study progestin levels with weight and BMI among women randomized to the progestin-only injectable contraceptives DMPA-IM and NET-EN

Progestin-only injectable contraceptives, mainly depo-medroxyprogesterone acetate intramuscular (DMPA-IM), are the most widely used contraceptive methods in sub-Saharan Africa. Insufficient robust data on their relative side-effects and serum concentrations limit understanding of reported outcomes in contraception trials. The WHICH clinical trial randomized HIV-negative women to DMPA-IM (n = 262) or norethisterone enanthate (NET-EN) (n = 259) at two South African sites between 2018-2019. We measured serum concentrations of study and non-study progestins at initiation (D0) and peak serum levels, one week after the 24-week injection [25 weeks (25W)], (n = 435) and investigated associations between study progestin levels, and BMI and weight of participants. Peak median serum concentrations were 6.59 (IQR 4.80; 8.70) nM for medroxyprogesterone (MPA) (n = 161) and 13.6 (IQR 9.01; 19.0) nM for norethisterone (NET) (n = 155). MPA was the most commonly quantifiable non-study progestin at D0 in both arms (54%) and at 25W in the NET-EN arm (27%), followed by NET at D0 in both arms (29%) and at 25W in the DMPA-IM arm (19%). Levonorgestrel was quantifiable in both arms [D0 (6.9%); 25W (3.4%)], while other progestins were quantifiable in ≤ 14 participants. Significant negative time-varying associations were detected between MPA and NET concentrations and weight and BMI in both contraceptive arms and a significant increase was detected for peak serum progestin concentrations for normal weight versus obese women. Contraceptive-related reported outcomes are likely confounded by MPA, more so than NET, with reported DMPA-IM effects likely underestimated, at sites where DMPA-IM is widely used, due to misreporting of contraceptive use before and during trials, and 'tail' effects of DMPA-IM use more than six months before trial enrolment. Peak serum levels of MPA and NET are negatively associated with BMI and weight, suggesting another source of variability between trial outcomes and a potential increase in side-effects for normal weight versus overweight and obese women. Trail registration: The clinical trial was registered with the Pan African Clinical Trials Registry (PACTR 202009758229976).

An overview of contraception in women with obesity

The use of safe and effective contraception is essential for preventing unplanned pregnancy in women of all body sizes. When counseling women with obesity about contraception, it is important to consider the pharmacokinetic alterations of obesity on various modern contraceptive methods. However, evidence is reassuring that most contraceptive methods are safe and effective in women with obesity. Individual countries and the World Health Organization have published Medical Eligibility Criteria to guide contraceptive selection in women with medical issues including obesity. When choosing contraception, specific risks of the method relative to any underlying medical disorders must also be balanced against the risks of unintended pregnancy in this group.

Best Practice Contraception Care for Women with Obesity: A Review of Current Evidence

The prevalence of obesity among females of reproductive age is increasing globally. Access to the complete range of appropriate contraceptive options is essential for upholding the reproductive rights of this population group. People with obesity can experience stigma and discrimination when seeking healthcare, and despite limited evidence for provider bias in the context of contraception, awareness for its potential at an individual provider and health systems level is essential. While use of some hormonal contraceptives may be restricted due to increased health risks in people with obesity, some methods provide noncontraceptive benefits including a reduced risk of endometrial cancer and a reduction in heavy menstrual bleeding which are more prevalent among individuals with obesity. In addition to examining systems-based approaches which facilitate the provision of inclusive contraceptive care, including long-acting reversible contraceptives which require procedural considerations, this article reviews current evidence on method-specific advantages and disadvantages for people with obesity to guide practice and policy.

Variability and quantification of serum medroxyprogesterone acetate levels

Quantification of serum progestin levels in clinical contraceptive studies is now routinely performed to understand progestin pharmacokinetics and to correct for unreliable self-reporting of contraceptive use by study participants. Many such studies are focussed on the three-monthly progestin-only intramuscular (IM) injectable contraceptive depot medroxyprogesterone acetate (DMPA-IM). Methods commonly used to measure serum MPA levels include liquid chromatography coupled to mass spectrometry (LC/MS) and radioimmunoassay (RIA); however, RIA methods have not been used in recent years. We review the available literature and find that these methods vary widely in terms of use of organic solvent extraction, use of derivitization and choice of organic solvent and chromatography columns. There is a lack of standardization of LC/MS methodology, including a lack of detailed extraction protocols. Limited evidence suggests that RIA, without organic solvent extraction, likely over-estimates progestin levels. Maximum MPA concentrations in the first two weeks post-injection show wide inter-individual and inter-study variation, regardless of quantification method used. Standardization of quantification methods and sampling time post-injection is required to improve interpretation of clinical data, in particular the side effects arising at different times depending on the pharmacokinetic profile unique to injectable contraceptives.

Pharmacokinetics, metabolism and serum concentrations of progestins used in contraception

Many different forms of hormonal contraception are used by millions of women worldwide. These contraceptives differ in the dose and type of synthetic progestogenic compound (progestin) used, as well as the route of administration and whether or not they contain estrogenic compounds. There is an increasing awareness that different forms of contraception and different progestins have different side-effect profiles, in particular their cardiovascular effects, effects on reproductive cancers and susceptibility to infectious diseases. There is a need to develop new methods to suit different needs and with minimal risks, especially in under-resourced areas. This requires a better understanding of the pharmacokinetics, metabolism, serum and tissue concentrations of progestins used in contraception as well as the biological activities of progestins and their metabolites via steroid receptors. Here we review the current knowledge on these topics and identify the research gaps. We show that there is a paucity of research on most of these topics for most progestins. We find that major impediments to clear conclusions on these topics include a lack of standardized methodologies, comparisons between non-parallel clinical studies and variability of data on serum concentrations between and within studies. The latter is most likely due, at least in part, to differences in intrinsic characteristics of participants. The review highlights the importance of insight on these topics in order to provide the best contraceptive options to women with minimal risks.

The contraceptive medroxyprogesterone acetate, unlike norethisterone, directly increases R5 HIV-1 infection in human cervical explant tissue at physiologically relevant concentrations

The intramuscular progestin-only injectable contraceptive, depo-medroxyprogesterone acetate (DMPA-IM), is more widely used in Sub-Saharan Africa than another injectable contraceptive, norethisterone enanthate (NET-EN). Epidemiological data show a significant 1.4-fold increased risk of HIV-1 acquisition for DMPA-IM usage, while no such association is shown from limited data for NET-EN. We show that MPA, unlike NET, significantly increases R5-tropic but not X4-tropic HIV-1 replication ex vivo in human endocervical and ectocervical explant tissue from pre-menopausal donors, at physiologically relevant doses. Results support a mechanism whereby MPA, unlike NET, acts via the glucocorticoid receptor (GR) to increase HIV-1 replication in cervical tissue by increasing the relative frequency of CD4+ T cells and activated monocytes. We show that MPA, unlike NET, increases mRNA expression of the CD4 HIV-1 receptor and CCR5 but not CXCR4 chemokine receptors, via the GR. However, increased density of CD4 on CD3+ cells was not observed with MPA by flow cytometry of digested tissue. Results suggest that DMPA-IM may increase HIV-1 acquisition in vivo at least in part via direct effects on cervical tissue to increase founder R5-tropic HIV-1 replication. Our findings support differential biological mechanisms and disaggregation of DMPA-IM and NET-EN regarding HIV-1 acquisition risk category for use in high risk areas.

Hormonal Contraception and HIV-1 Acquisition: Biological Mechanisms

Access to effective affordable contraception is critical for individual and public health. A wide range of hormonal contraceptives (HCs), which differ in composition, concentration of the progestin component, frequency of dosage, and method of administration, is currently available globally. However, the options are rather limited in settings with restricted economic resources that frequently overlap with areas of high HIV-1 prevalence. The predominant contraceptive used in sub-Saharan Africa is the progestin-only three-monthly injectable depot medroxyprogesterone acetate. Determination of whether HCs affect HIV-1 acquisition has been hampered by behavioral differences potentially confounding clinical observational data. Meta-analysis of these studies shows a significant association between depot medroxyprogesterone acetate use and increased risk of HIV-1 acquisition, raising important concerns. No association was found for combined oral contraceptives containing levonorgestrel, nor for the two-monthly injectable contraceptive norethisterone enanthate, although data for norethisterone enanthate are limited. Susceptibility to HIV-1 and other sexually transmitted infections may, however, be dependent on the type of progestin present in the formulation. Several underlying biological mechanisms that may mediate the effect of HCs on HIV-1 and other sexually transmitted infection acquisition have been identified in clinical, animal, and ex vivo studies. A substantial gap exists in the translation of basic research into clinical practice and public health policy. To bridge this gap, we review the current knowledge of underlying mechanisms and biological effects of commonly used progestins. The review sheds light on issues critical for an informed choice of progestins for the identification of safe, effective, acceptable, and affordable contraceptive methods.

Contraceptive Care of Obese Women

Importance

In the United States, 27% of reproductive-aged women are overweight, and 35% are obese. Until recently, contraceptive research excluded women greater than 130% of their ideal body weight. Gaps in data limit evidence-based decision making for effective contraceptive counseling and management in this rapidly growing population.

Objectives

The aims of this summary are to review the benefits, adverse effects, and risk factors associated with contraceptive methods in obese women, with special attention to effectiveness, and provide contraceptive management and counseling recommendations for best clinical practice.

Evidence Acquisition

We performed a thorough search of PubMed for current literature, including original research articles, review articles, and guidelines on contraceptive counseling and management in obese women in the United States. We reviewed the body of evidence with special attention to studies published since recent Cochrane and systematic reviews on this topic.

Conclusions

Contraceptive use is safer than pregnancy, especially for obese women who have increased pregnancy risks. Baseline health is compromised by obesity, but contraceptive risks remain low. Long-acting, reversible contraceptive methods offer superior effectiveness, minimal risk, and numerous noncontraceptive benefits across body mass index groups. No substantial evidence supports ineffectiveness of any method in obese women except oral emergency contraception and the patch. Pharmacokinetic changes of obesity associated with other oral methods do not seem to result in clinically significant declines in effectiveness. Future contraceptive efficacy studies should include obese women to better discuss their contraceptive needs.

Relevance

This review is beneficial for all providers caring for reproductive-aged women wanting to avoid unintended pregnancy.

Hormonal contraception and obesity

The rising rate of overweight and obesity is a public health crisis in the United States and increasingly around the globe. Rates of contraceptive use are similar among women of all weights, but because contraceptive development studies historically excluded women over 130% of ideal body weight, patients and providers have a gap in understanding of contraceptive efficacy for obese and overweight women. Because of a range of drug metabolism alterations in obesity, there is biologic plausibility for changes in hormonal contraception effectiveness in obese women. However, these pharmacokinetic changes are not linearly related to body mass index or weight, and it is unknown what degree of obesity begins to affect pharmacokinetic or pharmacodynamics processes. Overall, most studies of higher quality do not demonstrate a difference in oral contraceptive pill effectiveness in obese compared with non-obese women. However, data are scant for women in the highest categories of obesity, and differences by progestin type are incompletely understood. Effectiveness of most non-oral contraceptives does not seem to be compromised in obesity. Exceptions to this include the combined hormonal patch and oral levonorgestrel emergency contraception, which may have lower rates of effectiveness in obese women. The purpose of this review is to summarize evidence on contraceptive use in women with obesity, including differences in steroid hormone metabolism, contraceptive effectiveness, and safety, compared with women of normal weight or body mass index using the same methods.

Medroxyprogesterone acetate levels among Kenyan women using depot medroxyprogesterone acetate in the FEM-PrEP trial

Objective

To describe medroxyprogesterone acetate (MPA) levels among Kenyan depot medroxyprogesterone acetate (DMPA) users in the FEM-PrEP HIV prevention trial, and to compare MPA levels between ARV for HIV prevention (treatment) and placebo groups.

Study Design

We measured MPA in previously collected plasma samples from 63 Kenyan trial participants who used DMPA for one or two complete intervals. We separately assessed MPA levels among the nine DMPA users who became pregnant at this site.

Results

Mean MPA levels at the end of each 12 week injection interval were 0.37 ng/ml (95% CI: 0.25, 1.99) and 0.28 ng/ml (95% CI: 0.19, 1.22) among participants assigned TDF/FTC and 0.49 (95% CI: 0.40, 1.27) and 0.39 (95% CI: 0.31, 1.17) among those assigned placebo. The difference between groups was not statistically significant overall, or in an analysis which adjusted for the observed low adherence to TDF/FTC. Unanticipated findings of this analysis were low 12-week MPA levels among DMPA users in both study arms. Of 61 women who contributed data for the first DMPA injection interval, 26.2% had MPA levels < 0.1 ng/ml and 9.8% had levels below the detection level (0.02 ng/ml) at 12 weeks post-injection. Levels were similar at the end of the second injection interval. Five of nine women who became pregnant had levels below 0.15 ng/mL at the time of their last negative pregnancy test.

Conclusions

Use of TDF/FTC did not appear to affect serum MPA levels, however we found lower than expected MPA concentrations at the end of the dosing interval among DMPA users in the FEM-PrEP trial, the cause of which are unknown.

Implications

This study presents some of the few available data on MPA levels among DMPA users in Africa. The low levels among users described here, together with a number of pregnancies among DMPA users, are potentially concerning and require further investigation.

Contraception and sexual health in obese women

As the proportion of women with obesity increases worldwide, understanding the influence of body weight on sexual behavior, fertility, and contraceptive effectiveness is critical for health-care professionals and patients. Although many have theorized that obese women are different from normal-weight women regarding sexual health and behavior, current evidence for the most part disproves this. The exception is in adolescents where body image may play a role in riskier behavior, placing them at a greater risk of an unintended pregnancy. Given that most modern contraceptives were not originally evaluated in obese women, understanding how weight affects contraceptive pharmacokinetics and efficacy should be a focus of ongoing research. Evidence is reassuring that most modern contraceptive methods are safe and effective in obese women. This paper reviews what is known about sexual and contraceptive behavior, as well as the effectiveness and pharmacokinetics of modern contraceptives, for overweight and obese women.

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.

Serum medroxyprogesterone acetate levels in new and repeat users of depot medroxyprogesterone acetate at the end of the dosing interval

In the absence of published data on serum medroxyprogesterone acetate (MPA) levels in South African users, this study examines such levels in new and repeat users of depot medroxyprogesterone acetate at the end of the dosing interval. The study was undertaken at three family-planning clinics in Durban, South Africa. Serum MPA levels were measured in 94 Black African, Indian and White women returning between 11 and 14 weeks after their last injection. The median serum MPA level was 0.88 (range, <0.04-1.77) ng/mL and wide interindividual variability was observed. Levels in all but one woman were higher than 0.1 ng/mL, the level at which ovulation is reported to resume. MPA levels were not found to vary according to weight, body mass index or ethnicity. Although there was a slight tendency towards higher MPA levels with longer duration of use (r = 0.13), the wide interindividual variability precluded the possibility of determining whether this was a real trend. A prospective study, using standardized assay techniques and following individual women, is required to further clarify this issue.

Lunelle monthly contraceptive injection (medroxyprogesterone acetate and estradiol cypionate injectable suspension): effects of body weight and injection sites on pharmacokinetics

A new contraceptive option, medroxyprogesterone acetate (MPA) and estradiol cypionate (E2C) (MPA/E2C, Lunelle Monthly Contraceptive Injection), will soon be available for women in the US. This article reports the results of a US trial that assessed the effects of body weight and injection site on the pharmacokinetics of MPA, the progestin mediating contraceptive efficacy. This assessment was part of a nonrandomized, open-label, multicenter US study in healthy women receiving a monthly injection of MPA/E2C for 60 weeks. A total of 77 women (aged 18-47 years) at four centers participated in the pharmacokinetics assessment during the sixth or the seventh injection. For determination of serum MPA concentration-time profiles, blood samples were collected before the sixth and seventh injections (day 0) and on days 3, 7, 14, 21, and 28 after the sixth and seventh monthly administrations. For effects of injection site, MPA pharmacokinetics were compared at injection sites of the arm, hip, and leg. The pharmacokinetics of MPA, determined at the sixth and seventh injection, were not significantly affected by injection sites. The mean area under the curve (AUC0-28), however, was different between the arm and the leg injection sites; the difference was < 20%. More important, the average MPA trough concentrations (Cmin) at the fifth and sixth monthly injections were similar (range 0.42-0.51 ng/mL) for the three injection sites and well above the threshold levels of 0.10-0.20 ng/mL required to suppress ovulation. For effects of body mass index (BMI) on pharmacokinetics, women were stratified into three groups: thin/normal (BMI 18-28, n = 48), obese (BMI 29-38, n = 23), and highly obese (BMI > 38, n = 6). There were no significant differences in the pharmacokinetics of MPA among the three BMI categories. The only significant difference (p = 0.0387) was the AUC0-28 between BMI 18-28 and BMI 29-38. Because of the small sample size in the highly obese group, a reanalysis was performed by pooling subjects of the obese and highly obese groups. Results of the pooled statistical analysis remained the same. In summary, these results suggest that minor differences observed in the MPA pharmacokinetics--whether due to injection site or body weight or both--have no impact on the contraceptive efficacy of MPA/E2C, as trough concentrations (Cmin) are well above the threshold levels required to suppress ovulation. No dose adjustment is necessary based on body weight or injection site.

Pharmacodynamic effects of depot-medroxyprogesterone acetate (DMPA) administered to lactating women on their male infants

Normal postpartum women, who had a spontaneous vaginal delivery of one full-term male infant, free of congenital abnormalities and other diseases, were recruited for this study. Thirteen women received 150 mg depot-medroxy-progesterone acetate (DMPA), intramuscularly on days 42 + 1 and 126 + 1 postpartum. Infants of nine mothers, who did not receive DMPA, served as controls. Blood samples were collected from treated mothers on days 44, 47, 74, 124, 128, and 130 postpartum for medroxyprogesterone acetate (MPA) measurements. Four-hour urine collections were obtained from all 22 infants in the morning on days 38, 40, 42, 44, 46, 53, 60, 67, 74, 88, 102, 116, 122, 124, 126, 128, 130, and 137. Urinary follicle stimulating hormone (FSH), luteinizing hormone (LH), unconjugated testosterone, and unconjugated cortisol were measured by radioimmunoassay, and serum MPA and urinary MPA metabolites were measured by gas chromatography-mass spectrometry (GC-MS). No MPA metabolites could be detected in the urine of the infants from the DMPA-receiving mothers. Hormonal profiles in the urine samples were not suppressed in comparison with those of the control infants. The present study demonstrates that DMPA, administered to the mother, does not influence the hormonal regulation of the breast-fed normal male infant.

Interactions with oral contraceptives

The interaction of a range of different factors with the pharmacologic activity of oral contraceptives is reviewed. Pharmacokinetic interactions with oral contraceptives may occur (1) during absorption and extrahepatic circulation, (2) by interfering with protein binding, and (3) during hepatic metabolism. The hepatic mixed function oxidase system, which is mainly responsible for the metabolism of oral contraceptives, is affected by several different factors and is easily induced. Nutrition affects the activity of many drugs, but information regarding oral contraceptives is meager. Both pharmacokinetic and pharmacodynamic interactions, which may be synergistic or antagonistic, between the estrogen and gestagen components of oral contraceptives, are important, but there is no correlation between the rate of metabolism of the two components. Evidence suggests that some anticonvulsant, antibiotic, and antibacterial drugs may reduce the efficacy of oral contraceptives. Instances of interactions of other therapeutic agents are reported infrequently. The incidence of serious interactions is low and does not appear to have been reduced with low-dose oral contraceptives, probably because of large intersubject variability in the pharmacokinetics of oral contraceptives.

Comparative evaluation of contraceptive efficacy of norethisterone oenanthate (200 mg) injectable contraceptive given every two or three monthly. Indian Council of Medical Research Task Force on Hormonal Contraception

A total of 2388 subjects, 1181 for 60 +/- 5-day and 1207 for 90 +/- 5-day treatment regimen with norethisterone oenanthate (NET OEN) 200 mg injection, were observed for 24 months, constituting 28,513 woman-months. This clinical trial represents the largest clinical trial undertaken on NET OEN. The observations indicated that NET OEN given at 60 +/- 5-day intervals provides adequate contraceptive protection. However, as compared to the published studies elsewhere, higher method failures were seen during the first six months of NET OEN usage, when all women were receiving the drug at 60 +/- 5-day intervals. The reasons for this discrepant observation in the present study cannot be explained. The higher method failures reported with 90 +/- 5-day regimen were mainly during the third month following the injection, suggesting reduced contraceptive efficacy of the drug during this period. Thin build women (body weight less than or equal to 40 kg) were at higher risk of involuntary pregnancy. Disrupted menstrual pattern was the major reason for discontinuation ranging between 42-43 per 100 users at the end of 24 months. Amongst these, amenorrhoea was the commonest reason for discontinuation. No change in blood pressure was observed during contraceptive usage. The majority of NET OEN users did not show any change in body weight. The overall continuation rates with NET OEN were lower than those observed in similar conditions with Cu-T 200 mm2 IUCD.

Return of ovulation following a single injection of depo-medroxyprogesterone acetate: a pharmacokinetic and pharmacodynamic study

The effect of a single dose of 150 mg of depo-medroxyprogesterone acetate (DMPA) on pituitary, ovarian and endometrial function was assessed in relation to the peripheral levels of the compound in 8 women. The levels of medroxyprogesterone acetate (MPA), follitropin (FSH), lutropin (LH), prolactin, estradiol (E2) and progesterone ( Prog .) were measured 3 times a week during a pretreatment (control) cycle and then daily during postinjection weeks 14-17, 22-25 and 30-33. An endometrial biopsy specimen was obtained during postinjection weeks 17, 25 and 33. In three out of 8 subjects the daily hormone assays carried out during postinjection weeks 30-33 indicated anovulatory periods; in these subjects peripheral blood was drawn daily during postinjection weeks 46-49 and a fourth endometrial biopsy was taken during week 49.