AU8153387A

AU8153387A - Obstetrics cushion

Info

Publication number: AU8153387A
Application number: AU81533/87A
Authority: AU
Inventors: Jason Otto Gardosi
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-11-11
Filing date: 1987-10-30
Publication date: 1988-06-01
Also published as: DE3785926T2; WO1988003401A1; EP0290502B1; DE3785926D1; GB8626897D0; EP0290502A1

Description

OBSTETRICS CUSHION

This invention relates to obstetrics.

It is believed that an upright position in childbirth offers certain advantages. More particularly, it is thought to promote better alignment of the foetal head with the pelvic inlet to improve the "drive angle" of the pelvis and to lead to stronger and more efficient contractions. There is benefit from the removal (as compared with the supine position) of the weight of the womb from the underlying blood vessels. The force of gravity is made better use of with an upright posture and, finally, it has been shown that with certain upright postures the area of the pelvic outlet is significantly increased. Interest has in recent years revived in a variety of upright postures such as squatting, kneeling, sitting or standing. These postures are referred to in historical works and are also observed in other present-day cultures. In terms of equipment provided for obstetrics use, attention has been primarily focused on the delivery chair which has been put forward as an alternative to the conventional obstetrics bed.

In trials, delivery chairs have not always found acceptance with mothers in labour, possibly because of their constraining nature and the lack of freedom to change position. If care is taken to provide adjustability and to meet necessary hygiene standards, the resulting delivery chair can be expensive. Moreover, if a delivery chair is to be used in place of a bed, it should desirably permit rapid transfer of the parturient to a supine position for operative management in the face of complications. This agains increases costs. The expense leads to difficulties for obstetrics departments wishing to offer a choice between an upright delivery posture and the more conventional supine position. There is believed, moreover, to be a more fundamental disadvantage with known delivery chairs and this can be explained as follows.

The pelvic outlet is defined by the transverse separation of the innominate bones and by the an ero-posterior diameter measured from the sy physis of the pelvic bone to the sacrum. It will be recognised that physiological changes in late pregnancy include an increased mouldability of the pelvic joints. The joints between the sacrum and the innominate bones have in their upper parts a shallow ball and socket configuration allowing rocking movement of the sacrum. The lower part of the joint is flatter and allows for sliding of the sacrum, which is in this region generally wedge-shaped. In a squatting position, leverage from the femora on the innominate bones and weight of the trunk acting through the spine, will have the effect of separating the lower parts of the innominate bones and displacing the lower sacrum backward. Both these effects are beneficial in increasing the pelvic outlet area. Observed increases of up to 1cm in the transverse and up to 2cm in the antero-posterior diameter have been reported with an average increase in area of the pelvic outlet as compared with the supine position - of 2&%. An increase in the sub-pubic angle has the additional related advantage of enabling the foetal head to pass through the pelvis more anteriorly, so that episiotomy is less likely to be required.

It is believed that a sitting position fails to provide or is far less efficient in providing this desirable change in pelvic configuration. In sitting, a substantial portion of trunk weight is supported through the sacrum with a corresponding reduced proportion being supported through the femora. Even with the thighs abducted, the leverage exerted upon the innominate bones is significantly reduced as compared with the squatting position. Moreover, the sacrum may be rotated forward by reaction with the supporting seat surface, leading to a decrease in the antero-posterior diameter which is the opposite to the desired effect. This tilting of the sacrum forward may also pull the lower ends of the innominate bones together so decreasing further the size of the pelvic outlet.

It is an object of this invention to provide obstetrics equipment which promotes the adoption of a squatting or near squatting position, . which is comfortable and unrestraining and which is relatively inexpensive.

Accordingly, the present invention consists in one aspect in an obstetrics cushion adapted to be used with a back support, comprising two resilient thigh pads connected in spaced relation so as in use to underlie the parturient's abducted thighs, the cushion being so arranged that the adoption of a squatting position is promoted with a substantial fraction of body weight supported through the femora, the height of the thigh pads being such as to provide a sufficient cavity therebetween for generally vertical delivery of the foetal head.

Advantageously, the resilient thigh pads are connected by a resilient bridge portion having a front to back dimension which is small compared with the length of the thigh pads.

Preferably, the cushion is adapted for use with an obstetric bed having a back support. The obstetric bed is ideally height adjustable.

Alternatively, the cushion can be used with an integral or detachable back support. In one form of the invention the cushion is provided with handles enabling a force to be exerted through the parturient's arms.

In another aspect the present invention consists in an obstetrics cushion adapted to be used with a back support, the cushion comprising a bridge portion formed integrally with two resilient thigh pads extending therefrom so as in use to underlie the parturient's abducted thighs, the bridge portion having a front to back dimension which is small compared with the^~length of the thigh pads, so that adoption of a squatting position is promoted with a substantial fraction of body weight supported through the femora, the height of the thigh pads being such as to provide a sufficient cavity above the bed surface for generally vertical delivery of the foetal head. Preferably, the cushion is formed of plastics foam material having a fluid-tight skin.

This invention will now be described by way of example with reference to the accompanying drawings in which:-

Figure 1 is a side view of an obstetrics cushion according to this invention with a diagrammatic representation of an obstetrics bed;

Figure 2 is a front elevation;

Figure 3 is a plan view in direction A of Figure 1.

Figure 4 is a perspective view of an obstetrics cushion according to this invention; and

Figures 5 and 6 are sketches illustrating use of the cushion shown in Figure .

The obstetrics cushion shown generally at 10 in the drawings is formed of relatively firm plastics foam covered with a skin of impervious PVC or other suitable material providing a fluid-tight skin. The grade of foam used in this example is FL35F-

As shown best in Figure 3. the cushion comprises a bridge portion 12 formed integrally with thigh pads 14 and 16. Between the thigh pads, there is defined a cavity which is generally parabolic in plan. The front-to-back dimension of the bridge portion 12 is seen to be considerably less than the length of the thigh pads. In the described example, the ratio of these dimensions is approximately 1:3 and a ratio of at least 1:2 is preferred.

The cushion when viewed in side elevation as in Figure 1 takes the form, of a trapezium with the angle of inclination of the parallel generally upright edges being selected to match a typical angle between bed surface lδ and back support surface 20. The upper surface of the cushion is arranged to slope downwardly and rearwardly.

The cushion may be provided with a strap (not shown) fastened to the back support 20 and secured to the cushion through a burr-type fastener to prevent slippage of the cushion away from the back support.

In use, the relatively thin bridge portion 12 undergoes significantly greater vertical compression than the extensive thigh pads 14 and 16. With abduction of the thighs encouraged by the wide spacing of the thigh pads, this compressibility promotes a squatting or near squatting position in which there is relatively little trunk weight supported through the sacrum and a relatively large fraction of trunk weight supported through the femora. Weight is taken mainly through the femora through the thigh pads and, to a smaller extent, through the feet acting on the bed surface. If the parturient is encouraged to slide forwardly away from the bridge portion this weight transfer is accentuated. The squatting or near squatting position provides the advantages outlined above. Leverage in the femora acts to separate the pubic bones to increase the transverse diameter of the pelvic outlet and also the angle between the innominate bones. Not only is the sacrum no longer pushed forward, the movement of the innominate bones and the nature of the sacro-iliac joint also serve to move the sacrum backwards to increase the antero-posterior diameter. It should be recognised, however, that these improvements in pelvic configuration are achieved with the parturient retaining the comfort and the freedom to shift position offered by a bed and the benefit of other features of a delivery bed, particularly height adjustability. The resilience of the cushion according to this invention also increases comfort. If thought desirable, a support may be provided over the bed at a height at which it can be gripped by the hands. This offers an alternative ^•squatting posture which may be found more comfortable or more efficient. Use of the cushion enables easy movement between a near squatting position supported by the cushion thigh pads and a "hanging" squatting position in which the bar has a steadying effect.

The obstetrics cushion according to this invention can be manufactured inexpensively and it becomes feasible for an obstetrics department to have a cushion for each bed. The sealed nature and uncluttered contours of the cushion facilitate thorough cleaning. If it becomes necessary for the parturient to adopt a supine position, the cushion may simply be removed. A further advantage as compared with birth chairs is that the baby is delivered onto the bed surface. If desired, the bed may be provided with side handles below the cushion enabling the parturient to pull herself downwards, effectively increasing body weight and accentuating the described leverage effect in the femora. Referring to Figure , handles 30 are provided with padding 32 and are supported by an internal frame (not shown) . Figure 5 illustrates a rest position, whilst it is seen from Figure 6 that pulling on the handles 30 allows the maternal pushing to be directed downwards in the direction of the birth canal. This has been shown to help the parturient woman to co-ordinate the pushing efforts in the second stage of labour.

It should be understood that this invention has been described by way of example only and a variety of modifications are possible. It is important that the front-to-back dimension of the bridge portion of the cushion is small compared to the length of the cushion thigh pads to promote the described weight transfer. The exact shape of the cushion can, however, be varied. The outlet of the birth canal is elevated above the bed because of the height of the cushion and this, together with the U-shaped configuration of the thigh pads allows the birth attendant good access for controlling the delivery and room for lateral flexion of the baby's shoulders. The actual thickness of the cushion can, however, be^"varied and will be selected in combination with the compressibility. A variety of materials can be used to produce the cushion although foamed plastics are felt to offer advantages. The grade of foam can of course be selected as appropriate. It is desirable, but not essential, to provide means for securing the cushion to the bed and the described strap is but one example of such an arrangement.

The described handles may be provided on the cushion which is for this purpose suitably provided with a rigid base. In such a case, the orientation of the thigh pads may be determined solely through their respective connections with the base so removing the need for a bridge portion of foamed construction. The base serves as the bridge and the dimension of the bridge in the supporting surface beneath the pelvis has been effectively decreased to zero.

This alternative construction with the base serving to connect the two thigh pads may have advantages even where no side handles are provided. Still further means of connecting together the thigh pads may be devised which maintain the desired effect of ensuring that a substantial fraction of the body weight is supported through the femora rather than through the sacrum.

In a further modification, the cushion according to this invention is provided with an integral or detachable back support enabling use independently of an obstetric bed, in a home delivery for example.

Claims

1. An obstetrics cushion adapted to be used with a back support, comprising two resilient thigh pads connected in spaced relation so as in use to underlie the parturient's abducted thighs, the cushion being so arranged that the adoption of a squatting position is promoted with a substantial fraction of body weight supported through the femora, the height of the thigh pads being such as to provide a sufficient cavity therebetween for generally vertical delivery of the foetal head.

2. A cushion according to Claim 1, wherein the resilient thigh pads are connected by a resilient bridge portion having a front to back dimension which is small compared with the length of the thigh pads.

3. A cushion according to Claim 1 or Claim 2, wherein the cushion is adapted for with with an obstetric bed having a back support.

-i . A cushion according to any one of the preceding claims, further provided with handles enabling a force to be exerted through the parturient's arms.

5. An obstetrics cushion adapted to be used with a back support, the cushion comprising a bridge portion formed integrally with two resilient thigh pads extending therefrom so as in use to underlie the parturient's abducted thighs, the bridge portion having a front to back dimension which is small compared with the length of the thigh pads, so that adoption of a squatting position is promoted with a substantial fraction of body weight supported through the femora, the height of the thigh pads being such as to provide a sufficient cavity above the bed surface for generally vertical delivery of the foetal head.

6. A cushion according to claim 5_. further comprising an integral back support.

7. A cushion according to Claim 5 or Claim 6, further provided with handles enabling a force to be exerted through the parturient's arms.