Is Vyleesi Safe During Pregnancy? What Women Need to Know About Bremelanotide

The Short Answer: Vyleesi Is Contraindicated in Pregnancy

Stop here if you need a direct answer. Vyleesi is not safe to use during pregnancy. The FDA-approved prescribing information for bremelanotide places the drug in a category that requires discontinuation before or as soon as pregnancy is confirmed, based on animal reproductive toxicity data showing fetal weight reduction and increased fetal loss.

The drug was approved exclusively for premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD). The label explicitly states that bremelanotide should be discontinued when pregnancy is recognized. No controlled studies in pregnant humans have been conducted, which means any safety discussion rests on animal models and biological plausibility, not direct clinical evidence in pregnant women.

If you are currently pregnant and have been using Vyleesi, that discovery warrants a same-day call to your OB-GYN or midwife. The absence of human data does not mean the drug is safe. It means the risk is unknown, and unknown risk during pregnancy is treated as a signal to stop.

What Bremelanotide Actually Does in the Body

Bremelanotide is a melanocortin receptor agonist. It works primarily at the MC1R, MC3R, MC4R, and MC5R receptors in the central nervous system to modulate sexual desire pathways. Melanocortin receptors are expressed broadly across fetal tissue, including in developing neural structures, adrenal tissue, and skin. That broad receptor distribution is part of why reproductive toxicologists flag the class as concerning during organogenesis.

The drug is administered as a subcutaneous injection 45 minutes before anticipated sexual activity, with a maximum of one dose per 24 hours and no more than one dose per month recommended per the label. Its half-life is approximately 2.7 hours. Plasma concentrations fall quickly, but the biological window of fetal organogenesis, which runs from roughly 3 to 8 weeks after fertilization, is narrow enough that even short exposures during that window carry theoretical risk.

What the Animal Data Show (and Why It Matters)

Animal reproductive toxicology is the only formal safety data available for bremelanotide in pregnancy. The findings are not reassuring.

Rat Studies: Fetal Weight and Fetal Loss

In rat studies cited in the FDA label, bremelanotide administered subcutaneously during organogenesis at doses of 0.3 mg/kg per day produced reduced fetal body weight. At higher doses, increased post-implantation loss (a marker of early fetal death) was observed. The dose producing fetal weight reduction in rats is estimated to produce exposures that overlap with the human therapeutic exposure range at the 1.75 mg clinical dose. That overlap is the core pharmacological concern.

Rabbit Studies: Developmental Malformations

Rabbit embryo-fetal development studies showed increased rates of fetal malformations at doses above 0.3 mg/kg per day. Malformations included skeletal and visceral findings. Rabbits are used alongside rats in reproductive toxicology because their placental physiology approximates human placentation more closely than rodents do in certain respects. The rabbit findings reinforce the rat signal rather than contradicting it.

What Is Extrapolated, What Is Not

To be direct about the evidence gap (and this matters): every number above comes from animal models. The translation of animal reproductive toxicity data to human risk is imperfect. Some drugs that cause fetal harm in rodents are safe in humans; some that appear safe in animals cause human teratogenicity. There are no published controlled cohort studies, no pregnancy registries with meaningful enrollment, and no randomized data in pregnant women. The decision to contraindicate bremelanotide in pregnancy is precautionary and based on mechanism plus animal signal, not on documented human birth defects.

That precautionary stance is consistent with how ACOG approaches drugs with reproductive toxicity signals in the absence of human safety data. The absence of proven human harm is not the same as evidence of safety, and no reputable clinician would recommend continuing a non-essential medication with an animal teratogenicity signal once pregnancy is confirmed.

Pregnancy and Lactation Safety: The Full Picture

This section is required for every drug article on WomanRx and reflects the clinical information every woman deserves to have before starting, continuing, or stopping a medication.

Pregnancy Category and Current FDA Labeling Framework

Vyleesi received FDA approval in August 2019, after the 2015 Pregnancy and Lactation Labeling Rule (PLLR) replaced the old A/B/C/D/X letter categories. Under the PLLR system, the bremelanotide label contains a structured pregnancy subsection that states: animal studies have demonstrated fetal risk, there are no adequate and well-controlled studies in pregnant women, and the drug should be discontinued when pregnancy is detected.

Under the prior letter system, this profile would have mapped to Category D or Category X territory given the animal malformation data and the non-essential indication. For practical clinical communication, you can think of it as a drug to avoid in pregnancy.

If You Conceived While Using Vyleesi

Accidental conception during Vyleesi treatment is possible, particularly because HSDD affects premenopausal women across the full reproductive-age spectrum, including women who are not actively avoiding pregnancy or who use methods with typical-use failure rates.

Steps to take immediately:

• Discontinue Vyleesi as soon as pregnancy is confirmed or suspected.
• Contact your OB-GYN, midwife, or reproductive endocrinologist for a full first-trimester evaluation.
• Report the exposure through the FDA MedWatch system or by calling 1-800-FDA-1088. Palatin Technologies, the manufacturer, also collects exposure data and can be reached through the same reporting channel.
• Be prepared to discuss the timing of exposure relative to your last menstrual period, because organogenesis timing determines the window of greatest theoretical risk.

A first-trimester ultrasound to assess fetal anatomy and growth is standard practice after any exposure to a drug with an animal teratogenicity signal. Your clinician may also refer you for a targeted anatomy scan at 18 to 20 weeks.

Breastfeeding and Lactation

No human data exist on bremelanotide transfer into breast milk. The NIH LactMed database entry for bremelanotide states that no information is available on the clinical use of bremelanotide during breastfeeding. Because of the absence of safety data and the fact that the drug affects central melanocortin receptors that are present in developing infants, the standard clinical recommendation is to avoid bremelanotide while breastfeeding.

Bremelanotide has a relatively short half-life of approximately 2.7 hours, which theoretically means that drug levels would fall to near zero within 12 to 16 hours of a single dose. Some clinicians apply a "pump and dump" reasoning to drugs with short half-lives, but that approach has not been validated for bremelanotide, and LactMed explicitly does not endorse its use during lactation given the absence of infant safety data. The melanocortin system plays roles in infant feeding behavior, energy regulation, and stress response, creating a theoretical concern even for low-level infant exposure.

The postpartum period also deserves its own mention here. HSDD can emerge or worsen postpartum due to estrogen withdrawal, prolactin elevation, sleep deprivation, and relationship stress. The temptation to restart Vyleesi after delivery is understandable, but the drug should not be used during breastfeeding based on current evidence. Discuss alternatives with your clinician, including sexual health counseling and hormone evaluation once lactation ends.

Contraception Requirements During Treatment

The FDA label does not include a formal contraception mandate comparable to, say, isotretinoin's iPLEDGE program. However, the combination of a contraindicated-in-pregnancy status and the drug's indication in sexually active premenopausal women means that reliable contraception is a standard clinical expectation during treatment.

Clinicians prescribing Vyleesi should confirm that women who do not want to become pregnant are using effective contraception. Highly effective options include hormonal IUDs, copper IUDs, implants, oral contraceptives used consistently, or barrier methods used correctly. For women who are actively trying to conceive, Vyleesi is simply not compatible with that goal and should be discontinued before attempting pregnancy.

Who Vyleesi Is Approved For (and Who Should Never Use It)

Approved Population: Premenopausal Women with HSDD

Vyleesi is FDA-approved for premenopausal women with acquired, generalized HSDD, defined as low sexual desire that causes marked distress or interpersonal difficulty and is not better explained by another medical or psychiatric condition, relationship problems, or a drug effect. The key trials, RECONNECT I and RECONNECT II, enrolled premenopausal women aged 21 to 55. In those trials, a statistically significant improvement in satisfying sexual events was seen compared to placebo, though the absolute difference was modest: approximately 0.5 additional satisfying sexual events per month over placebo in the combined analysis.

Who Should Not Use Vyleesi

Beyond pregnancy and breastfeeding, Vyleesi is contraindicated in women with:

• Uncontrolled hypertension (the drug transiently raises blood pressure by approximately 6 mmHg systolic and 3 mmHg diastolic on average, with some women experiencing larger spikes)
• Known cardiovascular disease or high cardiovascular risk, given that blood pressure transient increases are consistent across the clinical data
• Concurrent use of naltrexone (pharmacokinetic interaction: bremelanotide reduces naltrexone AUC by approximately 35%)
• Hypersensitivity to bremelanotide or any component of the formulation

Life-Stage Considerations

Bremelanotide has not been studied in postmenopausal women, and it is not FDA-approved for that population. The physiology of HSDD differs across the lifespan. In postmenopausal women, declining estrogen and androgen levels are more central to the pathophysiology, and interventions such as hormone therapy, systemic or local estrogen, and off-label testosterone have a different evidence base. The Menopause Society notes that testosterone therapy has the strongest evidence base for HSDD in postmenopausal women, while bremelanotide's evidence base is specifically in premenopausal women.

In perimenopausal women with irregular cycles and residual ovarian function, the same pregnancy cautions apply as in younger premenopausal women: pregnancy remains possible until 12 consecutive months of amenorrhea, and contraception is advisable during Vyleesi use.

HSDD Across the Female Lifespan: Context for This Conversation

HSDD is estimated to affect approximately 10% of premenopausal women in the United States, making it the most prevalent female sexual dysfunction. Its prevalence rises in the perimenopause transition and postmenopause, but those populations fall outside Vyleesi's approved indication.

A useful way to think about HSDD management across reproductive life stages:

Reproductive years (not trying to conceive): Both FDA-approved options for HSDD in premenopausal women, flibanserin (Addyi) and bremelanotide (Vyleesi), are available. Both require avoiding pregnancy during use. Flibanserin is taken daily; bremelanotide is taken on demand. Neither has been adequately studied in pregnancy.

Trying to conceive: Neither drug is compatible with a conception attempt. Discontinue before stopping contraception. Consider sexual health counseling, relationship therapy, and hormonal evaluation (thyroid, androgens, estrogen) to identify and address modifiable contributors to low desire.

Pregnancy: No pharmacologic treatment for HSDD is approved or recommended. Psychosexual counseling and addressing sleep, pain, relationship dynamics, and body image changes are the evidence-based approaches during this life stage.

Postpartum and lactation: As above. Address hormonal and relational drivers first. Bremelanotide should not be used during lactation.

Perimenopause: Ovarian hormone fluctuations, emerging genitourinary syndrome of menopause (GSM), and mood changes all contribute to low desire. Vyleesi is not approved for perimenopause, and the overlap with possible pregnancy means contraception remains necessary. Hormone therapy addressing estrogen deficiency may improve desire indirectly by treating GSM symptoms, dyspareunia, and mood instability.

Postmenopause: Testosterone (off-label) has the strongest evidence base. Vyleesi is not approved for this population.

Nausea, the Most Common Side Effect, and Why It Matters in Pregnancy

The most common adverse effect of bremelanotide in the RECONNECT trials was nausea, occurring in approximately 40% of women in the treatment arm versus 1% in placebo. Nausea is also the first symptom many women notice in early pregnancy. This creates a practical clinical problem: a woman taking Vyleesi who develops new nausea may attribute it to the drug rather than recognizing it as a possible sign of pregnancy.

If you are using Vyleesi and develop nausea at times not associated with dosing, or nausea that persists longer than the typical 1- to 2-hour post-dose window, take a pregnancy test. Early pregnancy nausea typically begins 4 to 6 weeks after the last menstrual period. The overlap in symptom timing and the fact that Vyleesi is used in sexually active premenopausal women means unintended pregnancy should always be on the differential when nausea pattern changes.

Evidence Gaps and What Women Deserve to Know

Bremelanotide's clinical development program, like most drug development programs before the 2016 NIH policy requiring sex as a biological variable in all funded research, did not include pregnant women, did not study drug behavior across the menstrual cycle in any published subgroup analysis, and enrolled primarily women aged 35 to 52 in the key trials.

The menstrual cycle changes bremelanotide pharmacokinetics theoretically through shifts in plasma protein binding, hepatic blood flow, and renal clearance that vary across follicular and luteal phases, but no cycle-phase PK data have been published. This is a genuine evidence gap. Women metabolize drugs differently than men, and women's metabolic physiology changes across the cycle. The FDA's 2020 guidance on sex as a biological variable in drug development acknowledges the historical underrepresentation of women in clinical pharmacology studies and calls for cycle-phase PK analyses, but for bremelanotide this data does not yet exist in the published record.

The honest position: we know bremelanotide causes harm in animal pregnancies at doses near the human therapeutic range. We do not know whether it causes harm in human pregnancies. Given the non-essential nature of the indication, no ethical framework supports continuing the drug in pregnancy. The appropriate response to incomplete data in a non-essential treatment is precaution.

If you were exposed to Vyleesi early in pregnancy and are worried: report the exposure, get your first-trimester evaluation and anatomy scan, and work with a maternal-fetal medicine specialist if you have additional risk factors or concerns. The animal data, while concerning, involved continuous dosing in rats, not the single-dose, on-demand use pattern seen in clinical practice. That distinction may matter for risk magnitude, though it does not eliminate the concern.