Now that would be an most interesting case. To get that done, she could either be in the lucky position of still having eggs resulting in a healthy baby. Or she would use a frozen egg (and then Carl Philip and his children could know about her plan) or she would get an egg of a donator. But would the baby be then her offspring, and the one, who is first/second in line to the throne. Complicated question, that would make the modern world and old traditions clashing in an most interesting way

Then again these days all Royals seem to live with the motto "I´m creating my own rules"...so maybe Victoria could then adopt the baby, she has self carried. Or it would be declared automatically to her baby, because 200 years ago, they had no genetic tests either
Well, all grey theory...Miss "I love children & animal" would better reproduce yourself. Nearly 50 year old prince Albert is already enough of a "desperate figure", but an 50 year old crown princess or queen having decided to live alone and/or not having children is it even more...talking about double standards here.