Pregnyl

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Pregnyl

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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 Pregnyl

What is Pregnyl? Definition and Classification

Property Description
Active ingredient Chorionic Gonadotropin (hCG)
Form Lyophilized powder for injection
Pharmacological class Gonadotropins, Pituitary and hypothalamic hormones and analogues
Origin Biologically-derived polypeptide hormone
LH analogue Yes (mimics Luteinizing Hormone)

Pregnyl is a medication whose active component is Chorionic Gonadotropin (hCG), a powerful polypeptide hormone classified pharmacologically as a Gonadotropin. It functions essentially as an analogue of Luteinizing Hormone (LH), mirroring the action of the body's natural pituitary hormone to target specific receptors in the gonads. This classification is clinically recognized for its direct role in specific hormonal regulation. Human chorionic gonadotropin is included on the WHO Model List of Essential Medicines.

Composition, Origin, and Pharmaceutical Form

The active ingredient, Chorionic Gonadotropin (hCG), is a biologically-derived substance that, in its traditional manufacturing, was purified from the urine of pregnant individuals, establishing its origin as a natural compound. Pregnyl is supplied as a lyophilized powder for solution for injection, a stable, dry presentation housed in a vial, which requires reconstitution with an accompanying solvent prior to use. This specific form, a single-ingredient product, is uniquely intended for intramuscular or subcutaneous injection, ensuring that the large glycoprotein hormone is delivered systematically without degradation.

The General Purpose of Chorionic Gonadotropin

The general purpose of Pregnyl is to provide the precise and potent hormonal signal necessary to induce final maturation and secretion processes within the reproductive system. By substituting for the natural LH surge, its luteotropic action reliably facilitates key reproductive events. A common scenario for its use is in fertility protocols to trigger ovulation in women who have undergone follicular development. The drug's utility is defined as supporting essential reproductive events in the management of specific cases of infertility and hypogonadism.

Regulatory References

  1. clinical practice guidelines

What side effects are possible with Pregnyl?

Adverse Reactions and Safety Information

The safety profile of Pregnyl is defined by both common local reactions and less frequent, but potentially serious, systemic adverse reactions documented in regulatory sources.

Serious and Clinically Significant Adverse Reactions

The most serious risk documented, particularly in females undergoing ovarian stimulation, is Ovarian Hyperstimulation Syndrome (OHSS), which may progress rapidly into a severe, life-threatening medical event. OHSS involves a dramatic increase in vascular permeability, potentially leading to fluid accumulation and complications like ascites and pleural effusion.

Other serious documented risks include:

  • Thromboembolic Events: Formation of blood clots in venous or arterial vessels, which may result in serious outcomes such as stroke, pulmonary embolism, or deep venous thrombosis.
  • Ovarian Torsion: Twisting of the ovary, which can result in reduced blood supply and potential damage.
  • Severe Hypersensitivity: Immediate reactions such as anaphylaxis (a generalized, life-threatening allergic reaction) and angioedema have been reported.

Common Adverse Reactions

Reactions reported at the injection site are very common and may include bruising, pain, redness, swelling, and itching. Systemic reactions reported include headache, irritability, restlessness, depression, fatigue, and localized or generalized edema.

Safety Restrictions and Contraindications

Official regulatory documents contraindicate the use of this medicine in patients with:

  • Precocious puberty.
  • Androgen-dependent neoplasms (e.g., prostate or breast cancer).
  • Tumors of the hypothalamus or pituitary gland.
  • Uncontrolled non-gonadal endocrinopathies (e.g., thyroid or adrenal disorders).
  • Primary gonadal failure (indicated by high serum FSH).

Additionally, patients with generally recognized risk factors for thrombosis (such as severe obesity or a personal/family history of thrombosis) may face an increased risk of thromboembolic events.

Overdose and Emergency Response

Overdose of Pregnyl (Chorionic Gonadotropin) is not typically associated with acute life-threatening toxicity, but administration of too high a dose may lead to severe, hormone-driven complications. The principal documented manifestation of overexposure is Ovarian Hyperstimulation Syndrome (OHSS) in women. Early signs that require attention include severe pelvic pain, abdominal pain, nausea, diarrhea, and sudden, rapid weight gain.

Severe OHSS is classified by regulatory authorities as a serious medical event that may be life-threatening. Manifestations can include ascites (fluid in the abdomen), pleural effusion, oliguria, and significant electrolyte imbalances. A major documented complication is the potential for venous or arterial thromboembolism (blood clots).

In the event of suspected overdose or the development of severe symptoms, individuals must seek immediate medical attention. For cases involving serious OHSS, regulatory labeling advises that hospitalization should be considered, and the use of the medicine must be stopped. Treatment is officially defined as being symptomatic and supportive, emphasizing bed rest and careful fluid and electrolyte management, as no specific antidote is stated in the prescribing information. A distinct consideration is the risk of precocious puberty in prepubertal males; if this occurs, regulatory guidance dictates that therapy must be discontinued.

Therapeutic Uses of Pregnyl

What Pregnyl Treats: Main Uses and Benefits

Pregnyl is relevant within therapeutic areas related to hormonal insufficiency. Its application is relevant for managing conditions that include anovulation in women, hypogonadotropic hypogonadism in males, and certain manifestations of cryptorchidism and delayed puberty in prepubertal males.

This medication is applied in clinical settings that involve systemic imbalance, particularly when a lack of natural Luteinizing Hormone (LH) signaling is the issue. The treatment provides support that helps ease the overall burden of symptoms associated with subfertility and developmental delays.

“This treatment helps manage symptoms that interfere with normal reproductive and developmental functioning, offering supportive symptomatic assistance when natural hormone signals are insufficient.”

In fertility protocols, Pregnyl helps trigger the final maturation and release of the egg, an action critical for progression toward conception. In men with hypogonadism, it contributes to supporting the body’s natural production of testosterone and may assist with sperm production. For young boys, it is relevant for easing symptoms associated with physical development and may assist with testicular descent.


Quick Fact: Support for Hormonally-Driven Developmental and Reproductive Symptoms

Condition Category Symptom Management Role
Female Infertility (Anovulation) Helps trigger the final hormonal event relevant for egg release.
Male Hypogonadism Supports endogenous hormone production in situations involving low testosterone/sperm count.
Pediatric Delays (Cryptorchidism) Contributes to providing hormonal support to encourage physical maturation.

Eligibility and Restrictions for Use

Pregnyl (Chorionic Gonadotropin) is an analogue of Luteinizing Hormone whose eligibility is strictly determined by official regulatory criteria, including absolute prohibitions and conditional use requirements.

Absolute Contraindications

Pregnyl must not be used in patients presenting with the following conditions, as stated in the regulatory labels:

  • A known hypersensitivity or allergic reaction to Chorionic Gonadotropin or its excipients.
  • Known or suspected sex hormone-dependent tumors, such as carcinoma of the prostate, breast, ovary, or uterus.
  • Males with precocious puberty (early onset of puberty).
  • Females with primary ovarian failure, unexplained vaginal bleeding, or reproductive organ malformations deemed incompatible with pregnancy.
  • Patients with uncontrolled non-gonadal endocrinopathies (e.g., thyroid or adrenal disorders).

Conditional Use and Restrictions

Use requires caution and close monitoring in certain populations due to the drug’s potential to increase androgen production, which may cause fluid retention:

  • Patients with a history of cardiac or renal disease, epilepsy, migraine, or asthma.
  • Pediatric Use: Use in prepubertal boys for cryptorchidism requires monitoring to avoid premature epiphyseal closure or precocious sexual development.
  • Pregnancy and Lactation: The drug is contraindicated once pregnancy is confirmed. Caution is advised when administering to a nursing woman, as excretion into breast milk is not established.
  • Geriatric Use: Clinical studies did not include subjects aged 65 and over, and safety and effectiveness are not established in children under four years old.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory documents define the interaction profile of Pregnyl (Chorionic Gonadotropin) based on its chemical properties and the absence of certain formal studies.

Documented Interaction Patterns

Formal clinical studies investigating the pharmacokinetic or pharmacodynamic interactions between Pregnyl and other medicinal products have not been performed. Consequently, there are no documented interactions related to metabolic enzymes, such as the Cytochrome P450 system, or drug transporters.

There are also no known interactions documented in regulatory summaries concerning the consumption of food or drinks while using this product.

Interaction-Related Restrictions and Constraints

The prescribing information mandates specific procedural constraints for administration and diagnostic testing:

  • Pharmaceutical Incompatibility: Pregnyl must not be mixed with any other medicinal products in the same syringe or vial. This restriction is based on the absence of compatibility studies, which is necessary to maintain the physical integrity of the injection solution.
  • Diagnostic Interference: Following administration, Chorionic Gonadotropin may interfere with the immunological determination of serum or urinary hCG. This interaction can lead to a false positive pregnancy test result, an effect that may persist for up to ten days after the final dose. This is a crucial procedural constraint for healthcare providers and patients relying on these tests.

Mechanism of Action

Pregnyl contains human chorionic gonadotropin (hCG), a glycoprotein hormone that acts as an agonist at the Luteinizing Hormone/Choriogonadotropin Receptor (LHCGR). This G-protein coupled receptor is expressed prominently on Leydig cells in the testes and Theca/Luteal cells in the ovaries, with structural and functional homology to luteinizing hormone (LH).

Binding of hCG to LHCGR activates Gs alpha subunits, leading to the stimulation of adenylate cyclase. This enzyme catalyzes the conversion of ATP to cyclic adenosine monophosphate (cAMP), increasing the intracellular concentration of this second messenger. The elevated cAMP levels activate Protein Kinase A (PKA), initiating a downstream phosphorylation cascade that modulates transcription factors and key steroidogenic enzymes, such as Steroidogenic Acute Regulatory protein (StAR). This molecular pathway promotes gonadal steroidogenesis, driving the synthesis and secretion of androgens (e.g., testosterone) in males and progesterone in the corpus luteum in females. System-level consequences include sustained endocrine support for reproductive processes.

Dosage and Administration Information

Administration Overview

Pregnyl is administered via injection. The process involves preparing the medication from a powder form using a provided diluent. It is typically delivered either subcutaneously (under the skin) or intramuscularly (into the muscle), depending on the specific requirements of the treatment plan.

Preparation and Handling

The medication is supplied in a sterile vial as a dry powder. Before administration, it must be reconstituted with the accompanying sterile liquid. The following general principles apply to the handling of the product:

  • Visual Inspection: Before use, the reconstituted solution should be inspected for clarity. It should be free of particulate matter and discoloration.
  • Aseptic Technique: Maintaining a sterile environment during the mixing and injection process is essential to prevent contamination.
  • Immediate Use: Once the powder and liquid are mixed, the solution is generally intended for use as directed by the clinical protocol.

Injection Sites

The choice of injection site depends on the method of administration:

  • Intramuscular Injections: These are often administered into large muscle groups, such as the upper outer quadrant of the buttock.
  • Subcutaneous Injections: These are typically administered into fatty tissue areas, such as the abdomen (away from the navel) or the front of the thigh.

Rotating the injection sites is a standard practice to minimize local tissue irritation or discomfort.

Disposal of Materials

Used needles, syringes, and empty vials require proper disposal. These items are placed in a puncture-resistant sharps container to ensure environmental safety and to prevent accidental injury. Filled containers are subsequently managed according to local protocols for biohazardous waste.

Recent Clinical Evidence

Research Evidence / Overview of studies for Pregnyl


Studies in Women: To Support Ovarian Follicle Development and Release

Research has explored how the use of this medication was evaluated in studies involving fluctuating or unstable symptoms for women undergoing specific fertility treatments. Studies evaluated its association with the final steps of ovarian follicle development and release. These studies explored its use to mimic a natural hormone surge, which was observed in the studies to time the process of egg release (ovulation).

Findings describe patterns observed in the studies suggesting that this medication may be associated with patterns of hormonal events observed for the egg's release. However, comparative evidence is lacking with regard to certain long-term outcomes, and follow-up durations were limited in some reports. Certainty remains low for predicting individual outcomes, as findings describe group patterns, not personal outcomes.


Studies in Men: To Address Specific Conditions of Low Hormone Production

This medication was evaluated in studies of men with conditions marked by functional limitations due to low hormone production (hypogonadotropic hypogonadism). These studies explored its use to monitor changes in the testicles' production of their own hormones, specifically testosterone, and to assess its association with sperm development.

Research describes patterns observed in the studies regarding levels of testosterone within the testicles, which is an outcome related to systemic or functional imbalance. For men receiving other forms of hormone treatment, co-administration was observed in some studies regarding outcomes related to systemic or functional imbalance. While research provides insight into short-term changes, data are still emerging for certain subgroups, and subgroup findings are uncertain.


Studies in Prepubertal Boys: For Undescended Testes (Cryptorchidism)

This medication was observed in studies of prepubertal boys with undescended testicles. Studies explored whether its use was associated with the testes moving into the correct position in the scrotum. The incidence of outcomes reflecting daily functioning or activity level appears to be low when this medication was studied for use as a single treatment option. Evidence suggests that in an additional treatment setting (alongside surgery), it may be associated with changes in testicular growth and structure. Evidence quality varies across studies, and there is limited information for long-term outcomes.

Key Studies & References

  1. Pregnyl® (chorionic gonadotropin for injection, USP) - Official Prescribing Information (FDA DailyMed)

Frequently Asked Questions (FAQ)

Common questions about Pregnyl (FAQ)

Q: How long does the hCG from a Pregnyl injection remain detectable in the body?

Studies examining the medication’s properties describe the time it takes for the active ingredient, human Chorionic Gonadotropin (hCG), to be eliminated from the body. The mean terminal half-life of hCG is described as approximately 29 hours after administration.

Q: Can Pregnyl cause a false positive result on a home pregnancy test?

Yes. The active ingredient in this medication is the same hormone (hCG) detected by pregnancy tests. Due to this, the medicine may interfere with test results, which can lead to a false positive pregnancy test for a period that may persist for up to ten days after the final dose.

Q: How long does it typically take for male testosterone levels to normalize after starting Pregnyl?

Treatment for low hormone production in males is structured to support the body's own hormone production over time. For this reason, official dosing is structured as long-term, intermittent courses that may span several months, indicating that the stabilization of testosterone levels is not an immediate process.

Q: How long might it take to see a noticeable increase in sperm count in men taking Pregnyl?

Since the medication is intended to stimulate the development of new sperm cells, and this biological process occurs over an extended period, treatment regimens for low sperm count are structured to run for several months.

Q: What information is available regarding the use of Pregnyl while breastfeeding?

Official labeling advises caution when using this medicine while breastfeeding. This is because it is not established whether the active ingredient is excreted into breast milk. This information is used by healthcare providers to determine appropriate use during lactation.

Q: Are there any known interactions between Pregnyl and moderate alcohol consumption?

Regulatory summaries have not documented any known formal interactions concerning the consumption of food or drinks while using this product. Regulatory summaries focus on the official lack of documented interaction with food or drinks.

Q: Are there any known long-term health effects from using Pregnyl for fertility treatment?

Regulatory overviews indicate that comparative evidence is described as lacking with regard to certain long-term outcomes for patients after treatment. Similarly, follow-up study durations have been described as limited in some reports focusing on long-term effects.

Q: Can individuals with a history of migraines or epilepsy use Pregnyl?

Regulatory information indicates that patients with a history of conditions such as migraines or epilepsy require caution and close monitoring during use. This is due to the potential for the drug to increase androgen production, which may cause fluid retention.

Q: What kind of monitoring is typically required while a person is on Pregnyl treatment?

The effects of treatment are typically monitored according to official guidelines. This can involve procedures such as ultrasound scans of the ovaries for women, and the regular checking of blood hormone levels for both male and female patients.

Q: How is Pregnyl use addressed in individuals with high blood pressure or heart conditions?

Individuals with a history of conditions like cardiac or renal disease (kidney disease) require caution and close monitoring during use. This is primarily due to the potential for the medication to increase androgen production, which may lead to fluid retention.

Q: How is Pregnyl used in the treatment of men with low testosterone levels?

For low testosterone levels (hypogonadism) caused by certain medical conditions, the medication is administered by injection. Official protocols indicate that it is typically given two or three times per week over structured, intermittent courses that can span several months.

Q: What are the most commonly reported general side effects for women using Pregnyl?

Side effects more commonly reported in females include headache, painful breasts, and reactions at the injection site, such as bruising or pain. Mild Ovarian Hyperstimulation Syndrome (OHSS) is also listed as a commonly reported reaction.

Q: What are the most common side effects reported when men use Pregnyl?

Side effects more commonly reported when prescribed for men include acne, headache, fluid retention (edema), irritability, and reactions at the injection site. These are often related to the stimulation of androgen (male hormone) production.

Q: Is fluid retention (edema) a possible expected side effect of Pregnyl?

Yes. Fluid retention, or edema, is described in the official documents as a commonly reported systemic adverse reaction. It is a known effect related to the stimulation of hormone production caused by the medicine.

Q: Does Pregnyl affect mood, such as causing depression or irritability?

Official regulatory information lists changes in mood as adverse reactions that have been reported during treatment. Specifically, irritability and depression are mentioned among the common adverse reactions.

Q: What kind of research evidence supports the use of Pregnyl for fertility treatment?

Research has explored the use of this medication to mimic a natural hormone surge in women to time the process of egg release (ovulation). In men, studies have explored its use to monitor changes in the testicles' production of hormones like testosterone.

Q: What does the available evidence say about using Pregnyl for weight loss?

Prescription Chorionic Gonadotropin, the active ingredient, is not approved for use in weight loss. Furthermore, official labeling states it has not been shown to be effective as adjunctive therapy in the treatment of obesity.

Q: Does Pregnyl have an effect on appetite or fat metabolism?

Official labeling states the medication has not been shown to be effective as adjunctive therapy in the treatment of obesity. This is the only information provided regarding the medication's use or lack of use in relation to weight management.

Q: Is Pregnyl sourced from natural or synthetic ingredients?

Pregnyl contains a biologically-derived form of Chorionic Gonadotropin (hCG). The active ingredient is purified from the urine of pregnant individuals.

Q: What is the difference between Pregnyl and other brands of hCG, like Novarel or Ovidrel?

Pregnyl is a biologically-derived form of hCG, meaning it is purified from human urine. Other brands may utilize a recombinant form of hCG, which is manufactured synthetically in a laboratory setting.

Q: Does the vial of Pregnyl contain benzyl alcohol, and is this a concern?

The diluent provided with the medication, which is used to mix the powder for injection, is described in the official labeling as containing benzyl alcohol. This information is included in the full list of ingredients (excipients) for the product.

Q: Are there special instructions for discarding unused or expired Pregnyl?

For safe disposal, unused or expired medicine can be mixed with an undesirable substance, placed in a sealed container, and discarded in the household trash or taken to an authorized drug take-back program.

Q: Is Pregnyl safe to use for women who have a history of ovarian cysts or fibroids?

Official labeling includes restrictions for use in women who have fibroids in the uterus that could prevent a normal pregnancy, or a past or current history of ovarian cysts. Official documents describe these conditions as restrictions for use.

Q: Are there specific medical conditions men should report before starting Pregnyl treatment?

Official documents state that men with a history of precocious puberty or androgen-dependent tumors, such as prostate or breast cancer, are prohibited from using this medicine. Official documents describe these conditions as absolute contraindications for the use of this medicine.

Q: What are the differences between naturally-derived hCG and lab-created (recombinant) hCG drugs?

The difference relates to origin: naturally-derived hCG (like Pregnyl) is purified from human urine. Recombinant forms of hCG are manufactured synthetically in a laboratory. Both forms are described as different pharmaceutical products.

Q: Is Pregnyl an intramuscular (IM) injection or a subcutaneous (SC) injection?

The medication is administered via injection, and its official administration routes include both intramuscular (IM) injection and subcutaneous (SC) injection. The specific route used is part of the established administration protocol.

How should Pregnyl be stored and disposed of?

Official Storage and Disposal Guidelines

Pregnyl (chorionic gonadotropin) requires distinct, regulated storage conditions based on its state, as mandated by regulatory labeling.

Product State Storage Temperature Stability/Constraints
Unreconstituted Powder Controlled Room Temperature (15 C to 30 C) Keep in original carton; protect from light.
Reconstituted Solution Refrigerated (2 C to 8 C) Use within 60 days; Do Not Freeze.

The powder must be protected from light and kept away from moisture. When mixing, gently swirl the vial; do not shake. To meet safety standards, the medication must be stored out of the reach of children. Used needles and syringes must be immediately placed in an approved sharps disposal container for safe discard.

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

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