This increased the amount of pain the woman felt immediately after the operation, which could affect her immediate recovery as well as potentially influence other related factors such as breast feeding and parent-child bonding.
The lead researchers from the University of Bath (Dr Keogh) and Imperial College London (Dr Holdcroft) suggest that helping prepare the birth partner for a caesarean, both at antenatal classes and before the operation, could help reduce the pain experienced by the mother and improve the birth experience.
One in four babies born in the UK is now delivered by caesarean section (CS), with many hospitals delivering almost 30 per cent in this way. Fear of pain during childbirth is often cited as one of the contributory factors for the increasing rate of CS delivery.
But despite the popular notion that caesarean deliveries are the 'easy option,' with respect to overall pain experiences compared with labour pain, this may not be the case.
"Caesarean sections involve major surgery and are often performed whilst the mother is awake under regional anaesthesia which numbs the lower part of the body," said Dr Ed Keogh from the University of Bath.
"Whilst actual pain during a caesarean is usually more controlled than a vaginal delivery, the whole procedure is not painless.
"Women who have had a caesarean tend to experience much longer periods of postnatal pain and recovery. They also have mobility restrictions placed on them whilst they recover from the surgery, such as picking up heavy items, reaching upwards and driving.
"Whilst it has become a social expectation that birth partners accompany and support mothers during a caesarean delivery, it is unclear what part birth partners play in women's experience of childbirth.
"Whilst some women say that birth partners improve birth experiences, others report less positive outcomes. It is not unreasonable for the birth partner to have some feelings of anxiety and fear about the operation they are about to witness."
The women involved in the study were recruited from the Chelsea and Westminster Hospital in London during regular ante-natal check ups.
Almost all of the women (61) had chosen their husband or partner to be their birth partner, with just four deciding on a female birth partner.
The women and their birth partners were questioned before, during and after the delivery about their fears, expectations and experiences. The women were also assessed for their pain levels at different stages of the procedure and immediately afterwards.
The study revealed that those women who had negative birth expectations before the operation had the most fear experiences during the delivery, which in turn was related to greater post-operative pain.
It also showed that women are most afraid during the application of the nerve block used to numb the lower part of the body, rather than the initial incision as the researchers expected.
"Maternal fear fluctuates during a caesarean section but it can be influenced by the psychosocial factors around them, including their birth partner," said Dr Keogh.
"Anecdotally a number of birth partners told us that they had little choice in attending the caesarean operation and felt ill prepared.
"Birth partners can have potentially beneficial effects on maternal birth experiences. Rather than removing them from the operating theatre altogether, it would be better to target the emotional wellbeing of the birth partner to help reduce the anxiety and fear experienced by the mother.
"Since anxiety can increase recovery times, it would be useful to study whether increased maternal fear during the procedure has an impact on mothers, such as longer-term recovery from surgery as well as other related factors such as breast feeding and parent-child bonding."