She had two abortions, the first in the sixth month of pregnancy. In her own words:
[...] the baby was already well formed, and they chopped it up as they were pulling it out, and then brought it out in chunks. I suppose I was horrified, but by that time I was expecting anything -- it was like being in a butcher's shop. They gave me a local anaesthetic. They said they couldn't put me out otherwise they wouldn't have been able to perform the operation. I was fully conscious the whole time. There was a nurse holding me down, holding my head, and two men working down at the bottom, and I was in a most undignified position with my two feet strapped in those clamps they use to keep the legs apart. I kept saying (because I wanted a girl, incidentally), 'Will you just tell me whether it's a girl?' They just didn't answer. They took no notice of me at all. They simply got on with the job, working away at the bottom of the bed, with my feet held high in the air.
Caitlin Thomas with George Tremlett, Caitlin: Life with Dylan Thomas (Henry Holt and Company, 1988), p. 152