Levonorgestrel pharmacokinetics in plasma and milk of lactating women who take 1.5 mg for emergency contraception

Emergency contraception - A narrative review of literature

BACKGROUND

Emergency contraception includes several methods of contraception that can be used after unprotected sexual intercourse, after failure of any used method of contraception or in case of sexual abuse, to prevent pregnancy.

PURPOSE OF THE STUDY

The aim of the study was to analyze the available methods of emergency contraception, their mechanisms of action, efficacy, forms of administration, clinical applications and possible adverse effects.

MATERIAL AND METHOD

PubMed, Scopus and Cochrane datebases were searched for articles from 2010 to 2024 about emergency contraception.

RESULTS

The analyzed types of emergency contraception included single oral dose of ulipristal acetate, single oral dose of levonorgestrel and intrauterine system releasing levonorgestrel or copper intrauterine device. Taking emergency contraception in the optimum time according to the drug characteristics allows for avoiding pregnancy in more than 90% of cases (depending on the type of emergency contraception and time from unprotected intercourse). The analyzed literature shows that intrauterine copper intrauterine device is the most effective method of emergency contraception, also together with intrauterine system releasing levonorgestrel leading to the lowest rate of adverse effects.

CONCLUSIONS

Taking emergency contraception can result in various adverse effects, therefore it should be introduced after thorough analysis of woman's medical history, including gynecological and obstetric history and potential contraindications. Additionally, the patient should receive detailed information about the drug mechanism of efficacy and potential adverse effects.

Safety of Progestogen Hormonal Contraceptive Methods during Lactation: An Overview

BACKGROUND

Breastfeeding is a process for not only nourishing infants but also for building a unique emotional bond between mother and child. Therefore, the ideal contraception during lactation should not affect lactation (milk composition, milk volume) and offspring development.

OBJECTIVES

This study aims to analyze the literature on the safety of progestogen hormonal contraceptive methods during lactation.

METHODS

We conducted a thorough search across various databases, including the National Library of Medicine (PubMed), and the Cochrane Database, Drugs and Lactation Database (LactMed). Our search utilized specific phrases such as: "lactation" and "breastfeeding" and "oral contraception" with "drospirenone" or "desogestrel", with "subcutaneous etonogestrel implant" or "etonogestrel implant", with "levonorgestrel-releasing intrauterine system", and "emergency contraception", with "levonorgestrel" or "ulipristal acetate".

CONCLUSIONS

Based on published scientific reports, progestogen hormonal contraceptives can be considered a relatively safe solution for women desiring to continue feeding their infant with their milk while using hormonal contraception. It is important to seek guidance on selecting the best contraception method based on the latest medical knowledge, tailored to the individual needs and clinical circumstances of each woman and place of residence. A woman should always be informed of the potential risks of such a treatment and then allowed to make her own decision based on the knowledge received from a specialist.

Novel fluorescence approach for trace quantification of levonorgestrel in breast milk based on click reaction with benzonitrofurazan azide (NBD-AZ)

Although the great importance of oral contraceptive agents in birth control, their existence in breast milk became a cause for concern, since infant exposure to these hormones is associated with many health problems. Consequentially, developing a sensitive bioanalytical method for monitoring their concentrations in breast milk is an urgent demand to examine the safety or the risk of these compounds on infants. Levonorgestrel is one of the most common contraceptive hormones under concern. Despite the high sensitivity of the fluorometric methods, detection of Levonorgestrel by them is confined because its structure does not exhibit any fluorescence. For the first time, we proposed a promising click fluorescent probe, 4-azido-7-nitrobenzoxadiazole to react with the alkyne group of Levonorgestrel, to give a highly fluorescent triazole derivative that exhibited strong signal at wavelength of 544 nm after excitation at 470 nm. Reaction parameters impacting the fluorescence were cautiously studied and optimized. The suggested approach has been successfully applied in Levonorgestrel estimation in breast milk samples with linearity of (0.4-80 ng.ml-1) and low detection limit of 0.12 ng.ml-1without interferences from any biological components and with mean % recovery of 97.84 ± 2.73. Accuracy, sensitivity, selectivity, simplicity, and low-cost makes this approach a convincing, promising, and appealing alternative over reported analytical methods for Levonorgestrel bioanalysis in different matrices.

Society of Family Planning Clinical Recommendation: Emergency contraception

Emergency contraception (EC) refers to several contraceptive options that can be used within a few days after unprotected or under protected intercourse or sexual assault to reduce the risk of pregnancy. Current EC options available in the United States include the copper intrauterine device (IUD), levonorgestrel (LNG) 52 mg IUD, oral LNG (such as Plan B One-Step, My Way, Take Action), and oral ulipristal acetate (UPA) (ella). These clinical recommendations review the indications, effectiveness, safety, and side effects of emergency contraceptive methods; considerations for the use of EC by specific patient populations and in specific clinical circumstances and current barriers to emergency contraceptive access. Further research is needed to evaluate the effectiveness of LNG IUDs for emergency contraceptive use; address the effects of repeated use of UPA at different times in the same menstrual cycle; assess the impact on ovulation of initiating or reinitiating different regimens of regular hormonal contraception following UPA use; and elucidate effective emergency contraceptive pill options by body mass indices or weight.

Models and methods to characterise levonorgestrel release from intradermally administered contraceptives

Microneedle (MN)-based technologies have been proposed as a means to facilitate minimally invasive sustained delivery of long-acting hormonal contraceptives into the skin. Intradermal administration is a new route of delivery for these contraceptives and therefore no established laboratory methods or experimental models are available to predict dermal drug release and pharmacokinetics from candidate MN formulations. This study evaluates an in vitro release (IVR) medium and a medium supplemented with ex vivo human skin homogenate (SH) as potential laboratory models to investigate the dermal release characteristics of one such hormonal contraceptive that is being tested for MN delivery, levonorgestrel (LNG), and provides details of an accompanying novel two-step liquid–liquid drug extraction procedure and sensitive reversed-phase HPLC–UV assay. The extraction efficiency of LNG was 91.7 ± 3.06% from IVR medium and 84.6 ± 1.6% from the medium supplemented with SH. The HPLC–UV methodology had a limit of quantification of 0.005 µg/mL and linearity between 0.005 and 25 µg/mL. Extraction and detection methods for LNG were exemplified in both models using the well-characterised, commercially available sustained-release implant (Jadelle®). Sustained LNG release from the implant was detected in both media over 28 days. This study reports for the first time the use of biologically relevant release models and a rapid, reliable and sensitive methodology to determine release characteristics of LNG from intradermally administered long-acting drug delivery systems.

Pharmacokinetics of the 1.5 mg levonorgestrel emergency contraceptive in women with normal, obese and extremely obese body mass index

OBJECTIVE

To assess the pharmacokinetics (PK) of levonorgestrel after 1.5 mg oral doses (LNG-EC) in women with normal, obese and extremely obese body mass index (BMI).

STUDY DESIGN

The 1.5 mg LNG dose was given to healthy, reproductive-age, ovulatory women with normal BMI (mean 22.0), obese (mean 34.4), and extremely obese (mean 46.6 kg/m²) BMI. Total serum LNG was measured over 0 to 96 h by radioimmunoassay while free and bioavailable LNG were calculated. The maximum concentration (Cmax), time to maximum concentration (Tmax), and area under the curve (AUC) of LNG were assessed. Pharmacokinetic parameters calculated included half-life (t1/2), clearance (CL) and volume of distribution (Vss).

RESULTS

Ten normal-BMI, 11 obese-BMI, 5 extremely obese-BMI women were studied. After LNG-EC, mean total LNG metrics were lower in the obese and extremely obese groups compared to normal (Cmax 10.5 and 10.5 versus 16.2 ng/mL, both p<.01; AUC 208 and 197 versus 360 h × ng/mL, both p<.05). Mean bioavailable LNG Cmax was lower in obese (7.03 ng/mL, p<.05) and extremely obese (7.53 ng/ml, p=.198) compared to normal BMI (9.39 ng/mL). Mean bioavailable LNG AUC values were lower in obese and extremely obese compared to normal (131.6 and 127.5 vs 185.0 h × ng/mL, p<.05 for both).

CONCLUSIONS

Obese and extremely obese women were exposed to lower total and bioavailable LNG than normal BMI women.

IMPLICATIONS

Lower 'bioavailable' (free plus albumin bound) LNG AUC in obese women may play a role in the purported reduced efficacy of LNG-EC in obese users.

Emergency contraception: What is new?

Unintended pregnancy rates remain high throughout the World and increase the risk of poor maternal and infant outcomes. Most of unintended pregnancies occur in women who were not using contraception or who became pregnant despite the reported use of contraception. Women who have had recent unprotected intercourse including those who have had another form of contraception fail are potential candidates for this intervention. Currently used emergency contraceptive methods are pills that contain combined estrogen-progesterone, only progestin, antiprogestins and copper intrauterine devices. The most common form of this type of contraception is oral progestin-only pills (levonorgestrel). The most effective method is copper intrauterine devices followed by anti-progestins and oral progestin-only pills. The major pathogenesis of oral emergency contraceptives is the prevention or delay of ovulation. Although conception is possible on only a few days of the cycle, emergency contraception is offered when indicated without regard to the timing of the menstrual cycle because of uncertainty in the timing of the ovulation. Levonorgestrel and E/P regimes are most effective as soon as possible after unprotected sexual intercourse. A linear relationship has been shown between effectiveness and the time of dose. The effectiveness continues for 120 h, but it is recommended to be used within 72 h after intercourse. Intrauterine devices may prevent pregnancy when 5 d after ovulation.

Safety data for levonorgestrel, ulipristal acetate and Yuzpe regimens for emergency contraception

The World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC) provide recommendations for use of emergency contraceptive pills (ECPs), including levonorgestrel (LNG) and combined oral contraceptives (COCs). A new ECP formulation, ulipristal acetate (UPA), is now available worldwide. To determine whether LNG, UPA or COC (Yuzpe) ECPs are safe for women with certain characteristics or medical conditions, we searched the PubMed and Cochrane databases for articles published from date of inception until May 2015 pertaining to the safety of LNG, UPA or Yuzpe ECP use. For direct evidence, we considered studies that looked at safety outcomes among women with certain medical conditions or characteristics taking ECPs compared with women not taking ECPs. For indirect evidence, we considered studies that reported pharmacokinetic (PK) data for ECP use among women with certain medical conditions or characteristics and studies that reported safety outcomes among healthy women taking ECPs. Five studies provided direct evidence; of these five studies, four examined LNG or Yuzpe use among pregnant or breastfeeding women, and one reported risk of ectopic pregnancy among women repeatedly using LNG ECPs. Poor pregnancy outcomes were rare among pregnant women who used LNG or Yuzpe ECPs during the conception cycle or early pregnancy. Breastfeeding outcomes did not differ between women exposed to LNG ECP and those unexposed, and there was no increased risk of ectopic pregnancy versus intrauterine pregnancy after repeated use of LNG ECPs compared with nonuse. Forty-five studies provided indirect evidence. One PK study demonstrated that LNG passes into breastmilk but in minimal quantities. In addition, nine studies examined pregnancy outcomes following ECP failure among healthy women, and 35 articles reported adverse events. Studies suggest that serious adverse events are rare among women taking any of these ECP formulations.

IMPLICATIONS

Evidence on safety of ECPs among women with characteristics or medical conditions listed within WHO and CDC family planning guidance is limited. However, both direct and indirect evidence for our study question did not suggest any special safety concerns for the use of ECPs among women with particular medical conditions or personal characteristics, such as pregnancy, lactation or frequent ECP use.

ABM Clinical Protocol #13: Contraception During Breastfeeding, Revised 2015

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.

Assessment of effects of mifepristone administration to lactating mice on the development and fertility of their progeny

AIM

Mifepristone, a synthetic steroid compound that induces abortion, was recently found to potentially pass into human milk. This study aimed to determine the effects of mifepristone administration to lactating mice on the development and reproduction of their progeny.

METHODS

Lactating mice were gavage fed with mifepristone (8 mg/kg) daily for 4 days either from days 1-4 or from days 7-10 of lactation; controls received only peanut oil. Growth, mortality rate, organ weight to bodyweight ratio, sex hormone at 20, 40 and 60 days, fertility of these F1 progeny and litter size, sex ratio and mortality rate of the second generation were recorded.

RESULTS

No significant differences were observed in the average bodyweight, mortality rate of the female or male pups, and organ coefficient of uterus and ovaries of females in adulthood in comparison with the controls. However, the organ coefficient of testis at day 20 and 40 and testosterone concentration at day 60 were increased in male pups. Moreover, the reproductive capacity of the F1 pups was unaffected by 4 days exposure to mifepristone via their mother's milk: time to birth of F2 pups, litter size, sex ratio and mortality rate were similar to control F1 pups.

CONCLUSION

The study showed that treating lactating mice with 8 mg/kg mifepristone influenced only the organ coefficient of testis at day 40 and the testosterone concentration in male pups at day 60, however, it did not affect the development and fertility of female and male pups.

A systematic review of effectiveness and safety of different regimens of levonorgestrel oral tablets for emergency contraception

BACKGROUND

Unintended pregnancy is a complex phenomenon which raise to take an emergency decision. Low contraceptive prevalence and high user failure rates are the leading causes of this unexpected situation. High user failure rates suggest the vital role of emergency contraception to prevent unplanned pregnancy. Levonorgestrel - a commonly used progestin for emergency contraception. However, little is known about its pharmacokinetics and optimal dose for use. Hence, there is a need to conduct a systematic review of the available evidences.

METHODS

Randomized, double-blind trials were sought, evaluating healthy women with regular menstrual cycles, who requested emergency contraception within 72 h of unprotected coitus, to one of three regimens: 1.5 mg single dose levonorgestrel, two doses of 0.75 mg levonorgestrel given 12 h apart or two doses of 0.75 mg levonorgestrel given 24 h apart. The primary outcome was unintended pregnancy; other outcomes were side-effects and timing of next menstruation.

RESULTS

Every trial under consideration successfully established the contraceptive effectiveness of levonorgestrel for preventing unintended pregnancy. Moreover, a single dose of levonorgestrel 1.5 mg for emergency contraception supports its safety and efficacy profile. If two doses of levonorgestrel 0.75 mg are intended for administration, the second dose can positively be taken 12-24 h after the first dose without compromising its contraceptive efficacy. The main side effect was frequent menstrual irregularities. No serious adverse events were reported.

CONCLUSIONS

The review shows that, emergency contraceptive regimen of single-dose levonorgestrel is not inferior in efficacy to the two-dose regimen. All the regimens studied were very efficacious for emergency contraception and prevented a high proportion of pregnancies if taken within 72 h of unprotected coitus. Single levonorgestrel dose (1.5 mg) can substitute two 0.75 mg doses 12 or 24 h apart. With either regimen, the earlier the treatment is given, the more effective it seems to be.

Emergency contraception

This review will focus on the available methods for emergency contraception (EC), efficacy, side effects and mechanisms of action. Copper intrauterine device (IUD) has been shown to be the most effective method for EC which can be continually used for regular contraception. However, this possibility is seldom used and may be little known. Among the hormonal EC methods 1.5 mg levonorgestrel is the most widely used EC pill while the more recently developed Ulipristal acetate (UPA) has been shown to be the most effective option. This is probably due to a more pronounced prevention of follicular rupture compared with other hormonal EC methods. Knowledge is needed to better advise lactating women and obese women on optimal EC method. Furthermore a possible interaction of UPA with regular hormonal contraception and possibilities for "bridging" from EC to regular contraception needs to be explored. To increase efficacy future studies should focus on EC methods that target the endometrium.

Update on emergency contraception

Emergency contraception (EC) is any method used after sexual intercourse to prevent pregnancy. This article provides an overview of the history of EC methods and describes the current availability of oral and intrauterine EC. Oral forms include the Yuzpe regimen (combining ethinyl estradiol and levonorgestrel), levonorgestrel-only pills, and ulipristal acetate, which is a new emergency contraceptive drug recently approved by the US Food and Drug Administration. The copper T-380A intrauterine device can also be used for EC. Information about dosing, timing, access, and other considerations in the provision of EC is covered. Clinicians should be aware of all available options in order to counsel women in need of EC appropriately.

Nowadays which emergency contraception? Comparison between past and present: latest news in terms of clinical efficacy, side effects and contraindications

Despite many highly effective methods of contraception are available nowadays, many pregnancies are unintended. Emergency contraception (EC) is the use of drug or device after unprotected intercourse to prevent an unwanted pregnancy. It is a woman's last chance to prevent unintended pregnancy. Nevertheless the confusion about mechanisms of action, side effects, clinical efficacy and controindications makes the intervention underused in every setting investigated. So far levonorgestrel (LNG) has been considered the gold standard for oral EC. Today, a new type of second generation progesterone receptor modulator, ulipristal acetate (UPA) has been proposed as a more effective drug than LNG in prevention of unwanted pregnancies by delaying or inhibiting ovulation; even if many other devices are disposable in commerce. We revised the literature to concern most of the data available on the role of EC and moreover clarifying the available methods, the action windows of the accessible devices, the adverse events and the controindications.

Levonorgestrel used for emergency contraception during lactation-a prospective observational cohort study on maternal and infant safety

OBJECTIVE

To identify possible effects of levonorgestrel used as an emergency contraceptive during breastfeeding on mothers and their infants.

STUDY DESIGN

A prospective observational cohort study of all women who contacted the Teratology Information Service between January, 2005 and January, 2010. Breastfeeding women who used levonorgestrel as an emergency contraceptive (study group) were compared to breastfeeding women who used either ethynodiol diacetate or desogestrel (control group). Women were followed for 6-24 months. Main outcome measures were adverse maternal and infant effects and continuation of breastfeeding.

RESULTS

We followed 71 of 128 study group women and 72 of 100 control group women. Maternal adverse effects were mainly vaginal bleeding, which was less frequent in the study vs. control group (16 of 71 vs. 27 of 72, p = 0.068). Decreased lactation was uncommon and similar in both groups. Breastfeeding was reinitiated within less than 8 h in 75% of the levonorgestrel group women. Adverse infant effects were rare (0 of 72 infants vs. 2 of 72 infants, p = 0.5 in the study vs. control group).

CONCLUSIONS

Our findings support the safety of using levonorgestrel as an emergency contraceptive during lactation without the need for withholding breastfeeding.

Emergency Contraception Options: Focus on Ulipristal Acetate

Ulipristal acetate (UPA) is a progesterone receptor modulator that is available for emergency contraception (EC) and can be taken up to 120 hours after unprotected intercourse. A meta-analysis of clinical trials comparing UPA with levonorgestrel (LNG) for EC, demonstrated that UPA has higher efficacy than LNG. This higher efficacy is supported by biomedical studies that have demonstrated that UPA is a more potent inhibitor of ovulation, being able to delay ovulation in the immediate preovulatory period, when LNG is no longer effective. A recent study that explored risk factors for failure of EC, demonstrated that obese women were at increased risk of EC failure, with either UPA or LNG. However, failure was significantly less amongst women receiving UPA than those receiving LNG. There is growing evidence therefore, that UPA should be the preferred oral method of EC.

Emergency contraception: potential role of ulipristal acetate

Unintended pregnancy is a global reproductive health problem. Emergency contraception (EC) provides women with a safe means of preventing unwanted pregnancies after having unprotected intercourse. While 1.5 mg of levonorgestrel (LNG) as a single dose or in 2 doses with 12 hours apart is the currently gold standard EC regimen, a single dose of 30 mg ulipristal acetate (UPA) has recently been proposed for EC use up to 120 hours of unprotected intercourse with similar side effect profiles as LNG. The main mechanism of action of both LNG and UPA for EC is delaying or inhibiting ovulation. However, the 'window of effect' for LNG EC seems to be rather narrow, beginning after selection of the dominant follicular and ending when luteinizing hormone peak begins to rise, whereas UPA appears to have a direct inhibitory effect on follicular rupture which allows it to be also effective even when administered shortly before ovulation, a time period when use of LNG is no longer effective. These experimental findings are in line with results from a series of clinical trials conducted recently which demonstrate that UPA seems to have higher EC efficacy compared to LNG. This review summarizes some of the data available on UPA used after unprotected intercourse with the purpose to provide evidence that UPA, a new type of second-generation progesterone receptor modulator, represents a new evolutionary step in EC treatment.

Progesterone receptors and neural development: a gap between bench and bedside?

Despite a recent increase in the clinical use of progesterone in pregnant women and premature neonates, very little is understood about the potential role of this hormone and its receptors in neural development. Findings from rodent models indicate that the brain is indeed sensitive to progesterone during critical periods of development and maturation. Dramatic sex differences in progesterone receptor (PR) expression, in which males express higher levels of PR than females in specific regions, suggest that PR may play an important role in the sexual differentiation of brain and behavior and that the expression of PR may be one mechanism by which testicular hormones masculinize the brain. PR is also transiently expressed during fetal and neonatal development in areas of the brain associated with cognitive behaviors. PR protein and mRNA are expressed in pyramidal cell layers of perinatal cortex in an anatomically and developmentally specific manner, generating the intriguing hypothesis that progesterone is essential for normal cortical development. Basic research elucidating a potential role for progesterone and PR in developing brain is reviewed in light of the clinical use of this hormone. The necessity for future research integrating findings from the bench and the bedside is evident.