Unripe and semi-ripe papaya contain considerably more latex than fully ripe fruit. Research has found that crude papaya latex can cause uterine contractions in laboratory experiments, while a study using pregnant rats found no significant harmful effect from ripe papaya but did identify contractile effects from crude latex.
That distinction is important.
It does not mean that eating a normal serving of ripe papaya has been proven to cause miscarriage. The evidence concerning pregnancy is limited, and much of the experimental evidence involves animals or concentrated latex rather than ordinary servings of ripe fruit.
Nevertheless, because pregnancy is a situation where unnecessary risks should be avoided, pregnant people should discuss unripe or semi-ripe papaya with their healthcare professional.
What About Latex Allergy?
Papaya contains proteins associated with latex-fruit cross-reactivity.
Recent European food-safety assessments of papain and related enzymes from unripe papaya latex identify papain and chymopapain as known allergens and conclude that allergic reactions cannot be completely excluded.
If someone has a known latex allergy, it is sensible to ask a healthcare professional whether papaya should be avoided.
Anyone who develops symptoms such as swelling of the lips or throat, widespread hives, wheezing, or difficulty breathing after eating papaya should seek appropriate medical attention.
