Microval

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Medically reviewed

Laura Arias

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Microval

Quick Facts

Property Description
Active ingredient Levonorgestrel
Form Oral Tablet (Coated/Sugar-Coated)
Pharmacological class Progestogen-Only Contraceptive (POC)
Common use Contraception (Pregnancy Prevention)
Origin Synthetic Progestin

What is Microval and What Type of Contraceptive Is It?

Microval is a prescription hormonal contraceptive agent that is clinically recognized and classified within the family of Progestogen-Only Contraceptives (POCs), commonly referred to as the minipill. This medication is an oral tablet intended for systemic administration and is a single-ingredient product, containing only a progestin hormone and no estrogen. This formulation is often chosen in scenarios where estrogen is contraindicated, such as for lactating women or individuals with specific health conditions.


What Is Microval's Composition and Origin?

The sole active ingredient in Microval is levonorgestrel, a potent, low-dose synthetic progestin. Levonorgestrel is a man-made (synthetic) steroid hormone derivative that has been the subject of extensive pharmacological studies supporting its high efficacy profile. Microval is a monophasic formulation, meaning every pill delivers a consistent quantity of the hormone. The established use of levonorgestrel makes it a reliably targeted option for hormonal intervention.


What is the General Therapeutic Purpose of Microval?

The primary therapeutic purpose of Microval is pregnancy prevention, serving as a reliable method of daily contraception. This low-dose oral agent works via three established physiological actions: significant cervical mucus thickening, endometrial alteration (thinning of the uterine lining), and, in some users, ovulation suppression. The drug's mechanism is clinically confirmed to create a highly unfavorable environment for conception, providing consistent protection when used as a continuous daily method.

Regulatory References

  1. Levonorgestrel - WHO Essential Medicines List (eEML)

What side effects are possible with Microval?

Possible Side Effects and Safety Information

The official safety profile for Microval (levonorgestrel) is defined by categories of adverse reactions and specific safety constraints documented by governmental regulatory authorities.

Changes to the menstrual bleeding pattern—such as irregular bleeding, spotting, or the absence of bleeding (amenorrhoea)—are among the common and expected effects observed with this progestogen-only contraceptive. These changes are often most frequent at the start of treatment and may normalize over time. Other commonly documented effects affecting various system-organ classes include headache, nausea, changes in body weight, depressed mood, and breast tenderness.


Documented Serious Adverse Reactions

Although rare, regulatory documents specify potential serious adverse reactions. These include the risk of ectopic pregnancy, which requires evaluation if severe abdominal pain or amenorrhoea occurs. Additionally, rare risks associated with hormonal steroids, such as venous thromboembolism (VTE) and liver tumors (benign or malignant), are documented within the drug class safety profile.


Safety Constraints and Special Populations

Safety constraints restrict use in specific medical situations. The medicine is formally contraindicated in women with existing severe hepatic disease or a history of liver tumors. Use is also restricted in cases of known or suspected pregnancy and undiagnosed abnormal genital bleeding. For lactating women, the medicine is commonly used, as official documents generally indicate no adverse effects on infant health or development, despite the presence of small amounts of progestin in breast milk. The medicine provides no protection against HIV infection or other sexually transmitted infections.

Overdose and Emergency Response

Overdose and when to seek help

The official regulatory profile for an overdose of the Progestogen-Only Pill Microval is generally not associated with serious, life-threatening outcomes. Overdose manifestations are typically limited to extensions of known adverse effects and do not constitute a critical risk. Regulatory documentation confirms that serious undesirable effects have not been reported following the acute ingestion of large doses.


Documented Overdose Manifestations

Acute ingestion of larger than prescribed doses may result in specific clinical signs documented in official labeling. These manifestations include nausea and vomiting within the gastrointestinal system, as well as dizziness and somnolence (drowsiness) affecting the central nervous system. Females may also experience breast tenderness and the occurrence of withdrawal bleeding.


Emergency Response and Management

The mandated guidance for a known or suspected overdose situation is to seek immediate medical help and contact a Poison Control center right away. This action is required in all cases of overexposure. Treatment for an overdose of this low-dose oral contraceptive is non-specific; clinical management is officially directed toward providing symptomatic and supportive treatment to address the presenting signs. There is no specific antidote available or specified in the official prescribing information.

Therapeutic Uses of Microval

Microval is commonly used to help with daily hormonal management relevant for family planning, serving as a core component of therapeutic support for women requiring ongoing reproductive control. The Progestogen-Only Pill is considered a relevant therapeutic option commonly used in the domain of family planning.


Key Therapeutic Applications

The primary therapeutic purpose of this progestogen-only medicine is to assist with the management of the persistent risk of unintended conception. It is also relevant for managing heavy menstrual bleeding (hypermenorrhea) and painful cramping (dysmenorrhea), and may be applied across domains where additional symptomatic support is needed.

This medication is specifically used in clinical situations where a woman needs hormonal contraception but is medically restricted from using estrogen, which is common for key patient groups such as breastfeeding women and those with certain conditions like a history of blood clots or hypertension. This option may assist these women with accessing hormonal contraception that supports their unique health needs and postpartum care.

“This medicine may help patients cope more steadily with symptom fluctuations and supports general well-being during symptomatic phases.”


Quick Fact: Relief for Menstrual Symptom Burden

In situations where patients experience heavy menstrual bleeding and painful cramping, Microval may assist with managing these manifestations. This benefit supports patients during episodes of heightened discomfort and assists with maintaining functional stability during the menstrual phase.

Eligibility and Restrictions for Use

Microval (levonorgestrel 30 μg) is a Progestogen-Only Contraceptive (POC) with eligibility criteria strictly defined by regulatory authorities. The medicine is primarily intended for females of reproductive potential. A key allowance of the drug's labeled use is its suitability for lactating and breastfeeding women, distinguishing it from combined oral contraceptives. The medicine is not indicated for women outside of their reproductive years, such as those of prepubertal age or who are postmenopausal.


Contraindications (Who Must Not Use Microval)

Use of Microval is strictly prohibited (contraindicated) for women with the following conditions, as stated in the official regulatory documents:

Category Conditions
Hormone/Hepatic Known or suspected pregnancy, active liver disease, or history of steroid-dependent cancers (like breast or liver tumours).
Vascular History of or existing arterial or venous thromboembolic processes (e.g., DVT, stroke, or myocardial infarction).
Other Undiagnosed abnormal vaginal bleeding and hypersensitivity to the active ingredient or any excipients.

Use Restrictions and Cautions

Official labeling advises caution or defines restrictions for several populations. Caution is required for women with certain pre-existing conditions, including a history of hypertension, diabetes mellitus, or epilepsy. Furthermore, the safety and efficacy of Microval have not been specifically studied in patients with renal impairment.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The regulatory profile for Microval is defined by documented pharmacokinetic interactions that primarily affect the drug's systemic exposure. The main concern is co-administration with other medicinal products that induce CYP3A4 and other hepatic enzymes, a metabolic pathway responsible for Levonorgestrel's clearance. This enzyme induction can substantially decrease the plasma concentrations of Levonorgestrel, officially reducing its contraceptive effectiveness.

Exposure-Altering Substances

The following classes and specific substances are officially noted to reduce Levonorgestrel plasma levels, risking a reduction in efficacy:

Substance Category Examples (as listed in official documents)
Anticonvulsants Phenytoin, Carbamazepine, Primidone
Anti-infectives Rifampicin, Griseofulvin
Antivirals Efavirenz, HIV Protease Inhibitors (significant changes noted)
Herbal Products St. John's Wort (Hypericum perforatum)

Conversely, some strong CYP3A4 inhibitors may increase Levonorgestrel exposure. The co-administration of certain HIV protease inhibitors has been noted to cause significant changes (increase or decrease) in the progestin’s plasma levels. Furthermore, if a user experiences vomiting within a specific time window (e.g., two hours) of taking the tablet, official guidance addresses the need to consider a repeat dose due to a reduction in expected absorption. The interaction structure necessitates specific consideration of the reduced contraceptive efficacy when enzyme-inducing products are co-administered.

Mechanism of Action

How Microval Works: Mechanism of Action

The active component, levonorgestrel, functions as a synthetic progestin and acts primarily across three integrated mechanistic domains by engaging progesterone receptors.

Targeted Cervical Mucus Thickening

Levonorgestrel influences the progesterone receptors within the cervical canal glands. Activation of these receptors increases the viscosity and quantity of the cervical mucus. This localized effect creates a physical barrier that significantly impedes the passage and mobility of sperm into the upper reproductive tract.

Modulating the Neuroendocrine Pathway

This mechanism involves the active component influencing the Hypothalamic-Pituitary-Ovarian (HPO) axis through negative feedback. By dampening the signaling cascade that controls the release of Luteinizing Hormone (LH), the drug interferes with the LH surge required for follicular rupture. This modulates the ovulatory cycle by suppressing the release of the ovum (ovulation).

️ Altering Endometrial Receptivity

Levonorgestrel directly influences progesterone receptors in the endometrium (uterine lining), leading to glandular and stromal atrophy. This mechanism modifies the uterine environment by causing thinning and structural changes in the lining. The resulting physiological effect is the creation of an altered endometrial state that modifies receptivity.

Dosage and Administration Information

Microval is administered exclusively via the oral route, taken as one coated tablet containing 30 micrograms of levonorgestrel every day. The medicine is prescribed for a continuous daily regimen, meaning that one tablet is taken without interruption, even when bleeding occurs. This non-stop schedule is maintained for the entire duration that contraception is desired.

Adherence to a precise schedule is a core component of the usage pattern. The tablet must be taken at the same time every day to ensure the dose interval remains near 24 hours. The official labeling notes that the tablet is preferably taken after the evening meal or at bedtime. This strict time adherence is critical because the medicine's effectiveness is considered reduced if the interval between doses is more than 27 hours (a delay exceeding three hours).

If a tablet is missed, the high-level missed dose protocol requires the user to take the forgotten tablet immediately, even if this results in taking two tablets at the same time. The official instructions outline specific procedures for initiating therapy. When starting without prior hormonal use, an additional barrier method is required for the first days of the initial cycle. Furthermore, the official documents provide guidance for use in specific populations, such as rules for commencing the regimen in post-partum and breastfeeding women. These procedural rules define the standardized approach to commencing and maintaining the medicine's continuous administration.

Recent Clinical Evidence

Research evidence / Overview of studies for Microval

The research landscape for Progestogen-Only Contraceptives (POCs), such as Microval, includes studies examining its use for contraception and research on associated menstrual patterns. Research for this medication often involves follow-up periods of up to one year and includes real-world usage patterns to examine outcomes. Findings describe group patterns, not personal outcomes, and research provides context but not individual predictions.


Evidence for use in Pregnancy Prevention (Contraception)

Research has primarily examined the prevention of unintended pregnancy through randomized controlled trials (RCTs) and systematic reviews. Researchers typically monitored study participants over periods of one year to measure the primary outcome of unintended pregnancy rate. Findings describe patterns observed in the studies related to the consistency of prevention.

These studies explored how the medication was observed in conditions reflecting both perfect (ideal) use and typical (real-world) use. Data show patterns related to the importance of perfect daily adherence. Evidence is limited regarding how certain factors, such as the use of other medications, may affect the pill’s measured outcome.


Evidence for Associated Support in Menstrual Symptom Management

Research was studied for its potential association with changes in outcomes related to physical discomfort during menstruation, specifically heavy bleeding and painful cramping. These studies monitored changes in patient-reported outcomes over short- to intermediate-term intervals.

Research has described patterns of changes measured during the study period related to bleeding. These findings are often recorded as a secondary outcome rather than the primary focus of the initial clinical trials. The evidence for this use is limited because dedicated, large-scale RCTs are not as commonly available for this specific benefit as they are for contraception.


Research in Specific Populations

The Progestogen-Only Contraceptive was evaluated in specific groups of women who have health conditions or life stages that restrict the use of estrogen, such as lactating/breastfeeding women and individuals with contraindications to estrogen. Comparative evidence is lacking for certain subgroups, meaning subgroup findings are uncertain when trying to draw broad conclusions.

Key Studies & References Treatment of Irregular Uterine Bleeding Caused by Progestin-Only Contraceptives: A Systematic Review

Frequently Asked Questions (FAQ)

Common questions about Microval (FAQ)


Q: How long does it typically take for Microval to start working?

Official information outlines specific protocols for starting the pill regimen. Depending on the day of the menstrual cycle when the medication is first taken, official guidance suggests using an additional non-hormonal method for the first few days (for example, two or seven days). This temporary use of an extra method helps ensure protection until the medicine's full contraceptive effects are established.


Q: Does drinking alcohol affect how Microval works?

Regulatory drug product labeling generally does not report a direct interaction between moderate alcohol intake and the effectiveness of levonorgestrel-based contraceptives. Regulatory guidance emphasizes the importance of maintaining the precise daily dosing schedule, noting that alcohol consumption should not interfere with taking the pill at the same time every day.


Q: How quickly can a person get pregnant after stopping Microval?

According to official health guidance, the return to fertility is often quick after a person stops taking a progestogen-only pill. Because of this rapid return to a fertile state, it is possible for pregnancy to occur at any time immediately after discontinuing the drug. If pregnancy is not desired, official guidance suggests immediately considering other forms of contraception.


Q: What should I do if I experience unexpected severe side effects while on Microval?

Regulatory patient information advises that if you experience signs of serious adverse reactions, such as sudden severe abdominal pain or symptoms that suggest a blood clot, official guidance specifies that stopping the medication should be considered. In any of these situations, regulatory information advises seeking emergency medical attention.


Q: Does Microval have a black box warning?

Progestogen-Only Contraceptives (POCs) that contain levonorgestrel, the active ingredient in Microval, typically do not carry a specific FDA Black Box Warning. However, official drug class safety profiles do note warnings related to certain serious conditions, such as the potential for blood clots or liver disease.


Q: Can Microval be taken if I am a smoker?

Official prescribing information advises that careful assessment is necessary for all hormonal contraceptives in patients who have cardiovascular risk factors. While the primary concerns related to smoking are usually associated with estrogen-containing pills, smoking is considered a cardiovascular risk factor. Caution is advised by official sources in situations involving cardiovascular risk factors.


Q: What is the guidance on traveling across time zones while taking Microval?

Official information emphasizes the critical need to take the pill at approximately the same time every day, within a narrow margin of three hours. Official guidance related to managing this strict schedule suggests maintaining the original 24-hour dosing cycle. This typically means setting a new pill-taking time before or immediately upon arrival in the new time zone to ensure the pill interval remains consistent.


Q: Do any foods or specific juices interact with Microval?

While food interactions are generally not a primary concern, some official drug interactions databases suggest that the consumption of grapefruit juice may potentially increase the blood levels of levonorgestrel. Because of this potential change in absorption, its consumption is generally noted as needing to be limited or reviewed with a healthcare provider.


Q: Does Microval cause changes in skin condition or acne?

Skin changes, including conditions like acne and oily skin, are not universally listed as common adverse reactions for all specific progestogen-only pill formulations. However, reports of such skin issues are documented in official safety information for some forms of levonorgestrel-based contraception.


Q: Where can I find the official prescribing information for Microval?

The official prescribing information, such as the Summary of Product Characteristics (SmPC) or the DailyMed Label, is published by national regulatory bodies. The full regulatory text for the drug and its active ingredient, levonorgestrel, can be accessed through the public websites of authorities like the European Medicines Agency (EMA) or the Food and Drug Administration (FDA).


Q: What should I tell my dentist or surgeon about Microval before a procedure?

It is important to inform your medical team that you are taking Microval before any procedure, especially major surgery. This is because official information indicates that hormonal contraceptives may be associated with specific risks related to thromboembolism (blood clots) in surgical situations. Additionally, certain medications co-administered during a procedure could potentially affect the efficacy of the contraceptive.

How should Microval be stored and disposed of?

How to Store and Dispose of Microval

Microval (levonorgestrel) tablets must be stored at controlled room temperature, typically between 20 C and 25 C. It is mandatory to keep the medicine in its original, tightly closed container and protect it from moisture and light to maintain stability. The product must be stored out of the sight and reach of children and should never be used past its expiration date.

Disposal Requirements

Official regulatory guidance strongly recommends the use of a drug take-back program to dispose of unused or expired Microval. The tablets must not be flushed down the toilet or poured down a drain, as this medicine is not on the list for wastewater disposal. If a take-back program is unavailable, follow specific guidelines for household trash disposal, including mixing the medicine with an undesirable substance before discarding.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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