Pethidine is the only narcotic that midwives are licensed to prescribe. Up to 42 per cent of women are given the drug for pain relief during labour, and report dizziness, loss of control and disorientation as side effects. The Birth Stories community shared another effect that no one was warned about: hallucinations

Elliesparkle: Funny - I've never spoken to anyone else who mentioned Pethidine hallucinations. I hallucinated very badly on Pethidine during my first labour seven years ago.

I was given two full doses (not measured against body weight) which, as I was only nine stone, seemed a little excessive. It didn't help the pain, it just made me forget I was in labour (in fact at one point I thought I was eight years old again on a campsite) and therefore I couldn't understand why I was in such awful pain.

I got quite aggressive, and punched an ambulance man! Worst of all were the flashbacks - I had to change round the whole room I'd been in at the time and couldn't sleep properly for days (not good when you are breastfeeding as well).

The flashbacks were like mini panic attacks. Suffice to say, for my second labour, I refused any drugs in my house and said a rude word to the doctor when he called me in to suggest I got some 'just in case'. That birth was wonderful - and drug free.

Louiserovai: I had a shot of Pethidine and had a hallucination that the ward sister was jumping from bed to bed singing George Michael's 'Let's go outside', which was on the television at the time. I was adamant that this was happening and shouted at her when she came to examine me, asking, to her puzzlement, if she could keep the noise down.

My sister also hallucinated that Noel Edmonds was sitting on the end of her bed, and that the milkman kept coming in to see her. Are we the only ones? Pethidine doesn't seem to do anything for pain relief; I think they only give you it so they can have a laugh at what you come out with.

My mum also says that when she was having me she thought the clock kept coming down off the wall and telling her to hurry up.

Tollysmum: How terrific to hear that other people had Pethidine hallucinations. I was adamant that I would never have Pethidine again as I had hallucinated, but everyone looked at me very oddly and said they had never heard of this. My most recent midwife told me that she passed out completely on it though, so was very sympathetic.

For me it happened when I went up to the ward and little Maurice Sendak men (as in the illustrations for his book Where the Wild Things Are) kept trooping in long brown dragging overcoats and big floppy top hats. I knew they weren't really there, and it was quite entertaining in a completely peculiar way.

Gaeauk: I'm pregnant with my second at the moment, but when I had my first I was getting a bit hysterical because of the pain, so they offered me Pethidine injections to try and help me.

The next thing I know I'm seeing pink bunny rabbits with razors for claws coming to get me. I know it sounds bonkers now, but at the time it was so real that the midwife and my husband had to hold me down so I wouldn't run away from the killer bunnies.

I only had one injection and used gas and air for the rest - thankfully no more strange hallucinations.

brit2001: Not sure what this was, but I was given Pethidine with my second child as the contractions I was having were very painful compared to my first labour. I think it was because I was on a drip.

I was convinced the whole time that I was in labour in the dark. To me the room seemed dark and I just felt like I was sinking into the bed. When we spoke about this afterwards my husband informed me that the room was very well lit and it was light outside as I gave birth in the afternoon.

To be honest I didn't like the effect that Pethidine had on me at all - it made me feel totally out of control and sick