Final answer:
Leto cannot give birth because her uterus fails to contract during childbirth, which is essential for the delivery of the baby.
Step-by-step explanation:
Uterine contraction is a vital part of the labor process that helps to deliver the baby through the birth canal. If the uterus does not contract, this could lead to complications and the inability to give birth naturally. Moreover, being unable to give birth could also relate to a broader condition known as infertility, which is the inability of a sexually mature adult to reproduce by natural means, often defined by the failure to achieve a successful pregnancy after at least one year of regular, unprotected sexual intercourse.
In a broader context, issues such as irregular menstruation and not ovulating regularly, or damage to the reproductive organs, like testicular injuries, could lead to infertility. For women, hormonal imbalances can prevent the body from preparing for pregnancy and may prevent ovulation. The proper release of different hormones is essential for pregnancy and childbirth to occur. Complications such as venous embolism, where blood clots form in the legs, may also pose risks during pregnancy or after giving birth.
Your question is incomplete, but most probably your full question was
Leto is unable to give birth because ....
(Reference: Leto, the mother of Apollo and Artemis)