Short answer: The Pregnyl label lists, without percentages, headache, irritability, restlessness, depression, edema, fatigue and injection-site bruising, pain, redness, swelling and itching. In women, the key risk is ovarian hyperstimulation syndrome (OHSS), with stomach pain, nausea, diarrhea, enlarged ovaries and weight gain. In men, high doses can cause water and sodium retention, and gynecomastia or early puberty can occur.
What Pregnyl is approved for: Pregnyl (hCG) is approved for prepubertal cryptorchidism (undescended testicles) not caused by a physical blockage, for selected cases of hypogonadotropic hypogonadism in males (low testosterone from a pituitary deficiency), and to induce ovulation and pregnancy in anovulatory, infertile women whose anovulation is not from primary ovarian failure and who have been treated with human gonadotropins. The label states hCG has not been shown to be effective for treating obesity (Indications and Usage).
Source
PREGNYL (chorionic gonadotropin) for injection, prescribing information. Organon. DailyMed, version published December 4, 2025. DailyMed setid 1e94155f-19be-4944-b197-be4edbb4faf9
No. The current Pregnyl label has no boxed warning.
These are the label's own numbers from the Adverse Reactions section. Where the label compares with placebo (a dummy treatment), both columns are shown, so you can see how much more often a reaction happened on Pregnyl.
| Who and body system | Reactions the label lists |
|---|---|
| Males and females: immune system | Hypersensitivity reactions, both localized and systemic, including anaphylaxis; in rare cases, generalized rash or fever |
| Males and females: psychiatric | Irritability, restlessness, depression |
| Males and females: nervous system | Headache |
| Males and females: general and injection site | Bruising, pain, redness, swelling and itching at the injection site; occasionally allergic reactions, mostly pain and/or rash at the injection site; edema; fatigue |
| Females: vascular | In rare instances, thromboembolism, usually associated with severe OHSS |
| Females: respiratory | Hydrothorax, as a complication of severe OHSS |
| Females: gastrointestinal | Abdominal pain and gastrointestinal symptoms such as nausea and diarrhea, related to mild OHSS; ascites, as a complication of severe OHSS |
| Females: reproductive and breast | Unwanted ovarian hyperstimulation, mild or severe OHSS; mild to moderate enlargement of ovaries and ovarian cysts related to mild OHSS; large ovarian cysts (prone to rupture), usually with severe OHSS; painful breasts |
| Females: investigations | Weight gain as a characteristic of severe OHSS |
| Males: metabolism and nutrition | Water and sodium retention occasionally seen after high dosages, regarded as a result of excessive androgen production |
| Males: reproductive and breast | Gynecomastia (sporadically); precocious puberty |
The label lists these reactions by body system without percentages or a placebo comparison, split into reactions in both sexes, in females and in males.
OHSS develops after gonadotropin treatment has stopped and can come on fast, peaking about seven to ten days after treatment. It usually resolves on its own when the period starts, and the label says women are assessed for OHSS for at least two weeks after hCG.
For context, the label gives the U.S. background risk of major birth defects as 2% to 4% and of miscarriage as 15% to 20% of clinically recognized pregnancies.
If an allergic reaction is suspected, the label says Pregnyl is stopped and other possible causes are looked for.
The Warnings and Precautions part of the label lists these. Each line gives the label's heading and what it means in plain words.
Specialist use and monitoring. Pregnyl with gonadotropins is for physicians experienced with infertility, with proper monitoring available. Safe ovulation induction requires regular estradiol blood tests and transvaginal ultrasound.
Anaphylaxis. Anaphylaxis (a severe allergic reaction) has been reported with urine-derived hCG products.
Ovarian hyperstimulation syndrome (OHSS). OHSS causes fluid to leak quickly into the abdomen, chest and sometimes around the heart, and can become serious fast. Early signs are severe pelvic pain, nausea, vomiting and weight gain. It is more common, severe and long-lasting if pregnancy occurs, and severe OHSS may be life-threatening. hCG is withheld if OHSS seems to be developing before it is given.
Lung and blood vessel complications. Serious lung problems and blood clots in veins or arteries have been reported with gonadotropins, with or without OHSS, leading in rare cases to stroke, lost limbs, heart attack or death. Personal or family clot history, severe obesity and thrombophilia raise the risk.
Ovarian torsion. Twisting of the ovary has been reported after gonadotropins, including Pregnyl. Early diagnosis and untwisting can limit damage from lost blood supply.
Multiple pregnancy. Multiple pregnancies and births have been reported with all gonadotropin therapy, including hCG, and women are told of this risk before starting.
Birth defects, ectopic pregnancy and miscarriage. Birth defects after assisted reproduction may be slightly more common, which the label ties to parent factors and multiple pregnancies, not gonadotropins. Ectopic pregnancy is more frequent, so early ultrasound checks the pregnancy is in the womb. Miscarriage risk is increased, though causality is not established.
Ovarian tumors. Infrequent reports of benign and malignant ovarian tumors exist in women who had multiple drugs for ovarian stimulation; a causal link has not been established.
Fluid retention. hCG-driven androgen production can cause fluid retention, so the label urges caution in people with heart or kidney disease, high blood pressure, epilepsy, migraine or asthma.
Early puberty in boys. In boys treated for undescended testicles, hCG may cause precocious puberty; therapy is stopped if signs appear.
Lab test interference. hCG can cross-react in gonadotropin blood tests, especially LH, so the lab should be told the patient is on hCG.
Who should not use it. Prior allergy to gonadotropins or the ingredients; high FSH showing primary ovarian failure; uncontrolled thyroid, adrenal or pituitary disorders; tumors of the hypothalamus, pituitary, ovary, breast, uterus or prostate; reproductive organ malformations or fibroids incompatible with pregnancy; and unexplained abnormal vaginal bleeding.
From the Warnings and Adverse Reactions (the label has no Medication Guide; its Information for Patients says OHSS and multiple-birth risks are discussed before therapy) that comes with Pregnyl:
Dose Track has a side-effect log. Each entry records the symptom, a severity (none, mild, moderate, severe or life-threatening), the date and an optional note, and can be tied to a specific dose or logged on its own. The history screen shows what you logged over time, which makes it easier to tell your prescriber when a reaction started and whether it is easing. The app records what you enter; it does not judge whether a symptom is serious. For anything on the label's call-your-doctor list, call your doctor.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.