Ayahuasca and Pregnancy: Why It Is Strongly Advised Against

Pregnancy and breastfeeding are treated as firm contraindications for Ayahuasca, not because the drink is proven to harm a fetus, but because no one can show it is safe, and the known risks point the wrong way. There is no human safety data, the brew's beta-carboline alkaloids stimulate the uterus in animal and poisoning studies, it raises blood pressure and heart rate, and it reliably causes intense vomiting. Any responsible centre will screen out pregnant participants, and anyone who is pregnant, trying to conceive, or breastfeeding should speak to a clinician rather than a ceremony.

Is it safe to drink Ayahuasca while pregnant?

The honest answer is that no one knows, and that uncertainty is exactly why the standard guidance is "don't." There is no controlled human research on Ayahuasca in pregnancy, no studies measuring birth outcomes, fetal development, or long-term effects on children. What exists is a vacuum of evidence surrounded by several specific reasons for concern.

That distinction matters. A blanket "avoid" here is not built on proof of harm; it is built on the absence of any evidence of safety, combined with biological mechanisms that plausibly cause harm. In medicine, that combination is enough to advise against exposure. As a recent scoping review on psychedelics in pregnancy put it, clinicians should communicate that the evidence is insufficient to determine safety, that some studies report developmental concerns, and that the uncertainty is genuine.^[1]

If you want the broader picture of who is screened out and why, see our pillar on Ayahuasca safety and contraindications and our overview of who should not take Ayahuasca.

Why the lack of safety data is the core problem

For almost any medicine taken in pregnancy, regulators rely on a body of evidence: animal reproductive studies, registries, and careful human follow-up. Ayahuasca has essentially none of this in humans. You cannot ethically run a trial that exposes pregnant volunteers to a Schedule I / Class A substance, so the data simply does not exist.

What we do have is animal toxicology, and it is not reassuring. In a controlled study, pregnant rats were given Ayahuasca daily during gestation at one to eight times the typical human ceremonial dose. At higher doses, many of the mothers died and survivors showed kidney injury; the brew increased embryo deaths and the rate of fetal soft-tissue and skeletal anomalies, and it caused delayed intrauterine growth.^[2] Animal results never translate directly to humans, and ceremonial single doses are not daily dosing, but a study showing developmental toxicity in mammals is precisely the kind of signal that, in the absence of any human data, tilts the balance firmly toward caution.

When you cannot prove something is safe and you have real reasons to suspect it isn't, you don't expose a developing fetus to find out.

Uterine and cardiovascular effects in pregnancy

Beyond the missing data, two physiological effects make Ayahuasca a poor fit for pregnancy specifically.

The uterus. Ayahuasca's effects depend on beta-carboline alkaloids, harmine, harmaline, and tetrahydroharmine, from the Banisteriopsis caapi vine. These same harmala alkaloids are documented uterine stimulants. The related plant Peganum harmala, rich in harmine and harmaline, has a long history of use as an abortifacient, and a published case report describes a woman 22 weeks pregnant who developed uterine contractions after harmala poisoning, with subsequent fetal loss.^[3] That case involved a toxic overdose, not a ceremony, so it does not show that a ceremonial cup causes miscarriage. But it does demonstrate that these alkaloids can act on the pregnant uterus, a mechanism you do not want to test in early or late pregnancy.

The cardiovascular system. Ayahuasca raises blood pressure and heart rate through its monoamine-oxidase-inhibiting (MAOI) action, which increases circulating noradrenaline. Human pharmacology studies show transient but real increases in blood pressure, peaking around 60–90 minutes after drinking.^[4] Pregnancy already places extra demand on the heart and is itself a state where blood-pressure changes carry weight. Stacking an acute pressor effect on top of that, especially in anyone with, or at risk of, pregnancy-related hypertension, adds avoidable risk. (We cover the heart in more depth in Ayahuasca and your heart.)

Vomiting, dehydration and the "purge"

Vomiting is not a side effect of Ayahuasca so much as a defining feature of it, the purge is expected, and nausea and vomiting are the most commonly reported physical effects. Ceremonies also run for hours, often overnight, with little food or water beforehand.

For a pregnant person, repeated forceful vomiting and the dehydration that follows are real concerns in their own right. Pregnancy raises fluid needs, dehydration can reduce blood flow to the placenta, and severe vomiting in pregnancy is a recognised medical condition. An all-night ceremony built around purging is close to the opposite of the controlled, well-hydrated environment you would want.

What about breastfeeding?

The same logic extends past birth. There is no published data on whether Ayahuasca's alkaloids pass into breast milk or what they might do to a nursing infant. The lactation reference database e-lactancia rates these compounds as having limited compatibility with breastfeeding, citing the absence of milk-excretion data alongside the drug's potential for serious effects.^[5]

There is also a practical, child-safety dimension that has nothing to do with pharmacology: during and after a ceremony, a parent is in an altered, often incapacitated state for many hours and cannot reliably care for or feed an infant. Responsible guidance, including from lactation pharmacists, is to avoid the substance and to consult a clinician about timing if breastfeeding is involved.

How responsible retreats handle this

A well-run centre treats pregnancy as a hard exclusion, not a judgement call. Pre-arrival medical screening should ask directly about pregnancy and breastfeeding, and a credible facilitator will decline a pregnant participant rather than "work around" it. A centre that waves this away, or that frames ceremony as beneficial during pregnancy, is showing you how seriously it takes the rest of its safety obligations.

If you are evaluating a retreat, this belongs on your checklist. Our guides to choosing a retreat safely and the questions to ask an Ayahuasca retreat cover how rigorous screening should look, and a centre's handling of contraindications like pregnancy, heart conditions, and antidepressant interactions is one of the clearest signals of whether it is safe to trust with anything else.

The bottom line

The case against Ayahuasca in pregnancy is not built on a dramatic proven harm, and being honest about that is part of taking it seriously. It rests on four things together: a complete absence of human safety data; animal evidence of developmental toxicity; beta-carboline alkaloids that act on the uterus; and an acute cardiovascular load plus heavy vomiting and dehydration. None of those, on its own, would settle the question. Together, in a setting where a developing baby cannot consent and cannot be monitored, they make the responsible answer straightforward: not during pregnancy, not while breastfeeding, and any decision near either should run through a clinician who knows you.