Hon gjorde inte!

Barnet är hennes antagna dotter.

Skamlöst kopierat från MY EWN svar på SF & F

Det finns ingen specifik indikation på att Maddie är Clarke's daugher (barring advanced aging) eftersom hon tydligt är mer än 6 år gammal (mindre graviditetstid).

Jason Rothenburg, producent av The 100 ...

We wanted a reveal that Clarke survived and that her Nightblood kicked in, and she's now essentially — or so we think for the first couple of minutes of that final pop-out at the end — the lone survivor on the planet. Her friends... we know they made it to space, but she doesn't know whether or not they made it. We also know there's a group of 1200 led by Octavia (Marie Avgeropoulos) in the bunker, but Clarke is the lone survivor on the planet. And then we reveal she's found Maddy, this Nightblood child. Clearly, there's a maternal connection between the two of them when we reveal her in the end.

...

They have been together for years when we first see them. She's been with Maddy alone for a number of years; longer than she was ever on the ground with anybody. So it's going to be a very powerful bond and a huge part of season five.

Hollywood Reporter

Hittade indikerar inte en dotter åtminstone inte en födelsedotter.

Faktum är att ... vid en annan intervju ... bekräftar Rothenberg

The mother-daughter vibe that you pick up on in that scene is real. (It’s not her biological child; I think it’s fairly obvious that the kid is too old for that.) But she is a nightblood. Clarke was alone until she found Madi. When we find them together in [episode] 413, they have been together already for a number of years and are relying on each other and surviving together.

EW.com

När det gäller vem Maddy / Madi (stavningen varierar) är och var hon kommer från, är det ännu inte avslöjad i S5.