Were you able to unlock the Field?
I've seen some people with trouble finding the area, I was trying to identify if it was bad luck, looking on the wrong places or if there is a bug in unlocking the Field.
I can give you a few more details regarding the plan we have for the pregnancy feature

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The defeat birth scene remains as is, gives the idea that Leah spent some time being a breeding ground. Then any other "normal" scene will create a period of incubation for the eggs where Leah's belly will grow slightly depending on the egg size/quantity and then trigger a normal birth scene after a while. Parasite Worms will function as contraception as suggested before, and the Parasite Worm Big scene will only trigger when it has consumed some eggs.
Mosquitos will be part of the second case, but we won't be able to add them at the same time since we have to plan, request and animate the CGs. Either that or make image edits, which we will decide when we get there. We will also have a scene problem for the Leeches and the Cicada as well, so this may also be added on another version.
For now we're not planning pregnancy for the Parasite Beast and the Jellyfish, but we wanted to add a consequence or effect to the Jellyfish scene, since the Parasite Beast already has the Parasite Worms.
It will take a few versions into the extension roadmap until we implement the feature however, like you said, but any thoughts or ideas meanwhile are welcomed

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