This survey shows that techniques to protect the perineum against tearing during delivery are used by the great majority of midwives at Norwegian maternity departments. This is a result of changes in practice in recent years, according to the responses from the heads of 39 of 47 departments.
We chose to prepare a very short questionnaire in the hope of getting as many answers as possible. We were very successful in this respect, since we received responses from 83 % of the maternity departments. On the other hand, the questionnaire was so short that the amount of information we received from each department was limited.
We did not carry out any formal validation of the questionnaire, but it was adjusted after pilot testing. There is a certain risk that misunderstandings may have arisen as a result of weaknesses in the questionnaire. One major weakness is that all the answers were subjective, since we asked the heads of department to give their «impression» of practice at their maternity department. We do not know whether the heads of department have a realistic impression of what is going on in the delivery rooms. A better option might have been to ask all Norwegian midwives about their use of manual techniques to protect the perineum.
At the same time as the use of support techniques at Norwegian maternity departments appears to have increased, the incidence of sphincter rupture has decreased (12). It is difficult to know whether there is a causal relationship. Our survey is not appropriate for saying anything about this.
Theoretical considerations indicate that active support results in more controlled expulsion and slower emergence of the head. This reduces the pressure on the sphincter, which in turn reduces the risk of tearing. On the other hand, it is conceivable that the risk of rupture increases, for example if the deflection of the head during emergence results in an unfavourable head diameter so that the emerging head occupies more space than if it were flexed, as it usually is (13).
Several controlled studies have been performed where active manual techniques have been compared with more passive approaches (9) – (11). The results of these studies do not provide any unambiguous answer to whether the use of support techniques affects the risk of sphincter rupture. Nor can the possibility that support techniques do more harm than good be excluded. In one of the randomised studies, the frequency of third degree ruptures was several times as high in birthing mothers where manual manoeuvres had been used than in the others (10). In this study, a comparison has been made between the Ritgen manoeuvre and a passive approach without touching of the perineum (hands poised). The results of two other relevant randomised studies we know of had conflicting results with respect to the effect on the frequency of serious ruptures, but neither of the findings was statistically significant (9, 11).
Our study indicates that there has been a widespread introduction of support techniques among midwives at Norwegian maternity departments in recent years. The big question is whether this has contributed to the decline in the number of sphincter ruptures, which has taken place concurrently. The introduction of routine use of the modified Ritgen’s manoeuvre («Finnish manoeuvre») has been evaluated at five Norwegian maternity departments, where a dramatic decline has been reported in rupture frequency when a comparison is made between the incidence before and after the introduction of the intervention (6, 7). But an observed change from one time to another is seldom sufficient to allow the effects of a measure to be estimated – there may be a number of other reasons for the observed decline in the incidence of ruptures during this period. The strong focus on sphincter ruptures may have led to a number of changes that may have affected the frequency of ruptures. Without a control group, it is very difficult to assess how effective a measure has been. Simple before-and-after comparisons can be very misleading (14).
The results of our questionnaire survey indicate that it is no longer possible to perform a comparative study of a hands-on versus a more passive approach in Norway, since support techniques have now become standard procedure at the great majority of Norwegian maternity departments. This is positive for the women giving birth – provided that the use of these techniques reduces the risk of sphincter rupture – but negative with respect to the possibility of ascertaining whether it actually does so. A few years ago, the maternity departments could have been randomised to introduce routine use of hands-on or otherwise, but it is difficult to imagine today’s midwives taking part in an experiment where half of the maternity departments are randomised to re-introduce old methods.
In the absence of a robust evaluation, a thorough investigation should be made of the relationships between changes in the incidence of ruptures in recent years and measures that were introduced during the same period – using interrupted time series analysis. Such a study could contribute to substantiating any causal relationships.