Is pregnancy really worth the trouble when adoption is an option?

Most people who’ve had kids naturally say that pregnancy and the ensuing damages were worth it because their kids are so precious and important. I understand that, but I think if you adopted a kid you would feel the same way – aka, love them and feel like you would die for them, etc. So considering how hard pregnancy is on the body, not just during but even afterwards (substantial tearing, depression, weight gain, stretch marks, possible incontinence, etc) why do people more often than not choose natural childbirth over adoption? If you’re a mother, why was it worth it?