Abstract

Most women will use some form of transport during their pregnancy. Pregnant women should wear a correctly positioned safety belt which will protect them and their unborn baby. There is an accessory device marketed to keep the lap belt in the correct position. Airbags should not be deactivated. After maternal demise, the main cause of fetal loss in motor vehicle accidents is placental abruption. A pregnant woman involved in an accident should attend hospital after all but the most minor of accidents. Maternal resuscitation is vital to fetal survival. A Kleihauer test to detect fetomaternal haemorrhage should be performed and all Rhesus negative women should receive anti-D.
Most women feel able to start driving 1-3 weeks after a vaginal birth and 6 weeks after a caesarean section.
Midwives have an important role to play in correctly advising women on how to travel safely.

Introduction

The use of motor cars and access to public transport are considered essential in developed societies, despite any environmental consequences or the hazard of vehicle accidents. Few women would not travel by private or public transport in pregnancy: In the United Kingdom (UK), 81% of pregnant women have a full driving licence and 30% use their cars in relation to work.1 Up to 3% of women are involved in motor vehicle accidents when pregnant, fortunately most of these are of a minor nature, though a few (1-3%) result in fetal loss. Seatbelts are known to reduce fetomaternal trauma, but there is ignorance as to correct usage among both pregnant women and health professionals. Travel, its consequences, and issues of safety are therefore important topics for health professionals involved in the provision of maternity care and education. This article will principally refer to travel by car though other means of transport will also be discussed.

The law in the UK

In 1983, it became a legal requirement in the UK to wear a seatbelt in the front of a car. In 1991, it became a legal requirement to wear a seatbelt irrespective of where one is sitting in the car and this applies equally to pregnant and non-pregnant women.

Compliance with the law
A survey of pregnant women by Johnson and Pring, assessing knowledge of the law and seatbelt usage, showed limited knowledge of the legal requirement, although drivers were more aware than non-drivers. Compliance with legislation was high for those in the front seats, but women appeared reluctant to wear a seat belt in rear seats. The 1998 Confidential Enquiries into Maternal Deaths (CEMD) highlighted the importance of seatbelt use in pregnancy, and encouraged health care professionals to promote usage. An audit subsequent to this report showed an apparent increase in the use of seatbelts by rear seat passengers. The most recent Confidential Enquiries into Maternal Deaths report further emphasises the need for women to be made aware of the correct use of seat belts. The report highlights the cases of four women who died during pregnancy as a result of car accidents. One woman, wearing an incorrectly positioned lap belt suffered a ruptured uterus and her fetus, a breech presentation, was forced up into her chest.

Protection of the mother and fetus Seatbelts

Why wear a seatbelt during pregnancy?
Crosby et al showed that seatbelts are a major safety feature in pregnancy. The major cause of fetal demise in motor vehicle accidents is maternal death. Therefore, by protecting the mother and decreasing the risk of death in an accident, seatbelts indirectly protect the fetus. The death rate for pregnant women not wearing a seatbelt is twice that for women wearing seatbelts.

How to wear a seatbelt in pregnancy
Research has shown that a three-point seatbelt (lap-and-diagonal seatbelt) should be used, rather than a lap belt alone, although if only a lap belt is provided, such as in a rear seat, then it is preferable to wear this rather than no restraint at all as maternal protection is paramount to fetal survival. The lap belt should be placed under the 'bump' and should fit snugly across the hips, whilst the diagonal or shoulder belt should go over the shoulder, between the breasts and around the bump. There should be no seatbelt over the bump itself. The height of the diagonal belt should be adjusted to keep it away from the neck, but in contact with the shoulder. Additional safety devices have been devised to maintain seatbelts in the approved position with the belt below the bump. The Be-Safe Pregnant belt 15 is commercially available in the UK and in Europe. It conforms to European Union (EU) regulations and has received certification from the Swedish National Testing and Research Institute. Hopefully, possession of such a device would not only promote correct belt placement but be an encouragement for the pregnant woman to wear a belt at all times.

Why should a rear seat passenger wear a seatbelt?
Many people (including 31% of pregnant women) do not wear a seatbelt when travelling in the back of the car, as opposed to only 2% who fail to wear a seatbelt when in the front. However, it has been calculated that in a 30 mile per hour crash, an unrestrained back seat passenger will travel forward with a force of between 30 and 60 times their own body weight, which can result in severe, perhaps even fatal, injuries both to the passenger and to others travelling in the car.

Airbags
Airbags have been shown to protect both drivers and passengers during motor vehicle accidents, especially during frontal collisions; they save lives. However, as the abdomen enlarges in pregnancy, it moves closer to the airbag housed in the dashboard or steering wheel. There is some concern that the impact of a deployed airbag may cause fetal death. In the United States and Canada the advice is that the distance from the breastbone to the centre of the steering wheel should be at least 25 cm. Thus, a pregnant woman should push her seat as far back as possible to put as much distance as possible between her abdomen and the airbag. Because airbags may be life-saving in frontal collisions, experts advise airbags should not be deactivated for pregnant women, whether they are passengers or drivers, as, on balance, they exert more of a protective than harmful role. Further research into the use of airbags by pregnant women is needed.

Driving after pregnancy
There are no national guidelines on when it is safe to drive either after a vaginal birth or after a caesarean section. However, a survey by Johnson et al has shown there is there is a general agreement that it is safe to start driving 1-3 weeks after vaginal birth. Opinions are more divided with regard to caesarean section, with the medical profession feeling it would be safe to drive 3-6 weeks after a caesarean section, whilst midwives and pregnant women feel it safer to delay driving until 6 weeks.
As a guide, women should practise an emergency stop and reversing. When these manoeuvres can be performed with ease it should be reasonable to start driving again.

Other modes of travel

Coach and bus
It is not a legal requirement to wear a seatbelt either in a minibus with an unladen weight of more than 2,540kg or in a coach. However, it is suggested that they should be worn if they are provided. They must be worn in smaller minibuses than described above.

Rail travel
Seat belts are not provided on trains, despite the high velocity at which trains travel. In addition, people are allowed to travel standing in the aisles when seats are full, increasing the potential for injury, both to the pregnant woman and to fellow travellers.

Air travel
There is an obligation to wear a seatbelt during take-off and landing and it is recommended that the seatbelt should be worn throughout the flight. Standard lap belts are provided except for aircrew. Airlines limit travel in late pregnancy, due to the risk of labour and late pregnancy complications.

Motorcycles
Women are unlikely to travel by motorcycle in the second half of pregnancy, as it becomes increasingly difficult to get on to and drive a motorcycle or ride as a pillion passenger. As a result there has been no published information about motorcycling and pregnancy. In the first trimester, the uterus is still entirely contained within the pelvis so, unless an accident results in fracture of the pelvis, it is unlikely to be detrimental to the fetus.

Road traffic accidents
Mechanism of the accident and its implications to mother and fetus
Women involved in road traffic accidents at speeds of more than 50miles/hour (80km/hour) are more likely to die or sustain serious injuries, and there is a high incidence of abruption and fetal death prior to arrival in hospital. Broadside collisions are more likely to result in uterine tenderness or uterine irritability.21 Women involved in such accidents may therefore require a period of observation in hospital. If the woman is asymptomatic in the first few hours of admission, symptoms are unlikely to develop later. Frontal collisions usually occur at lower speeds and these are less likely to have deleterious consequences on the pregnancy.

Maternal and Fetal injuries associated with RTA

Maternal injuries
A pregnant woman may receive severe and multiple soft tissue, visceral and bony injuries in a road accident. Acetabular fractures are uncommon since the introduction of seatbelts. The uterus is protected within the bony pelvis in the first trimester, though even then it is susceptible to injury if there is major pelvic fracture.

Uterine rupture
Findings suggestive of uterine rupture include maternal hypovolaemic shock, tenderness or guarding on abdominal palpation, an abnormal fetal lie with easy palpation of fetal parts due to the fetus lying outside the uterus, and an inability to palpate the fundus of the uterus, if this is the site of rupture. When suspected, laparotomy is indicated.

Fetal injuries
Fetal injuries are usually due to indirect trauma in the form of shearing forces resulting in placental abruption, deceleration, or rapid compression.
Fetal loss occurs in approximately 40% of major trauma victims, as opposed to a fetal loss of 4% in women sustaining minor injuries. However, since most accidents are minor, the total number of fetuses lost as a result of minor trauma, is larger than that due to severe trauma.

Placental abruption
After maternal death the main cause of fetal loss in a motor vehicle accident is placental abruption.4,5 It can also endanger the woman's life because of subsequent disseminated intravascular coagulation. Placental abruption occurs in 1-5% of minor accidents and 20-50% of major accidents.4 It usually presents with vaginal bleeding and or abdominal pain, less commonly with uterine irritability, hypertonic uterus or fetal death (15%).

Transplacental haemorrhage
Fetomaternal haemorrhage, where fetal blood cells make their way into the maternal circulation, occurs in 8-30% of pregnancies complicated by an accident. A Kleihauer-Betke test, detects the presence of fetal cells in the maternal circulation and gives a reliable estimate of the size of the bleed, which may be large enough to result in fetal exsanguination. However, even small bleeds are important to detect in rhesus negative women, as they may lead to isoimmunisation, with development of antibodies to the antigens on the surface of rhesus positive cells, and rhesus disease in subsequent pregnancies. As little as 0.01mL of Rhesus-positive blood is enough to cause sensitisation in Rhesus-negative women. Thus all Rhesus-negative women involved in a motor vehicle accident should be offered Anti-D. The Kleihauer test should also be performed, as a proportion of women will have larger bleeds than the 4ml neutralised by the standard dose (500iu) of anti-D and therefore will need a higher dose.It should also be considered in Rhesus-positive women to evaluate possible transplacental exchange, which may be of both clinical and medicolegal interest.

Other injuries
Fetal intra-thoracic injuries have been reported with only minimal maternal trauma. Thus, some suggest that a chest X-ray of the neonate, as well as an ultrasound scan of the brain, should be performed on the babies of all women involved in a road traffic accident (RTA) at any time during the pregnancy.

Management of a pregnant woman who has been involved in a RTA

All women involved in an accident should be advised to contact their maternity care provider or attend the accident and emergency department. Also, one should determine the type of restraint, if any, that they were wearing at the time of the accident, as it has a bearing on the type of injuries both mother and fetus may have sustained. In major accidents, management should be as for the non-pregnant victim, as maternal stabilisation is vital to fetal survival, with attention to airway, breathing and circulation. Maternal shock is associated with approximately 80% fetal mortality. When recumbent, the pregnant woman should be tilted to the left, to prevent compression of the major vessels by the gravid uterus decreasing placental blood supply. The fetus should then be assessed as part of an obstetric examination, palpating the uterus to detect irritability, hypertonicity or tenderness. A speculum examination should be considered to look for cervical dilatation, which may be precipitated by the uterine irritability and rupture of membranes. Cardiotocographic (CTG) monitoring should also be arranged to look for fetal compromise; it is suggested that the CTG should continue for four hours. When maternal resuscitation is failing, caesarean section is considered, as it improves venous return and may allow better resuscitation of the mother. To increase the chances of fetal survival, it should be performed within five minutes of loss of maternal vital signs.

Information dissemination

Knowledge of mothers, midwives, GPs and consultants
Education has been shown to increase use of and promote correct seatbelt positioning in pregnant women.35 Surveys of health professionals have shown that they may neither be sufficiently well informed or motivated enough to give advice on travel safety. A postal survey of midwives' knowledge about safe travel in pregnancy revealed that 73% knew that there is a legal requirement to wear a seatbelt both in the front and back of a car. 45% could not correctly identify how to wear a seatbelt and only 78% of respondents would advise a woman to always wear a seatbelt.
GPs in England were inaccurate in their placement of seatbelts and knowledge of the law. GPs in Ireland were less aware of the legal requirement of seatbelt use, but were similar in their knowledge of where to place the seatbelt.36 These surveys highlight the importance of further education of all health professionals about the benefits of using a seatbelt in the car, as well as how to wear one correctly. GPs felt that they were able to give advice but rarely volunteered information; 52% felt that seatbelt information should be given by midwives at booking; 51% felt that information should be given at antenatal classes; 32% felt the information should be provided by antenatal clinic; and only 7% felt that GPs should provide information on the correct use of car restraints. It would be interesting to see whether this lack of knowledge and motivation has changed since the recommendations in the 1998 CEMD. Women report that their major sources of information on car safety are from the nationally produced Health Education Authority [now Health Promotion England] Pregnancy book39 (17%), health leaflets (8%) and midwives (6%), friends and magazines.1
Clearly, midwives are perceived as an important educational resource by both GPs and pregnant women. All women should now be given a leaflet at their first antenatal visit explaining the benefits of wearing a seatbelt as well as how to wear the restraint. Considerable information is now available on the internet, although numerous sites accessed via search engines using keywords of seatbelts and pregnancy contain information of little or no relevance. A comprehensive leaflet Seat belts and child restraints, published by the Department of the Environment, Transport and the Regions, can be obtained, free of charge, by telephoning 0870 122 6236 or can be downloaded from the internet: www.think.dtlr.gov.uk/pdf/seatbelt.pdf

Conclusions

* All women should wear a seatbelt in the front and rear of the car, correctly positioned
* Consider use of tested safety device to keep seatbelt correctly placed
* Do not deactivate airbags
* All pregnant women should be alerted to contact hospital if they are involved in a RTA beyond 12 weeks gestation
* Consider Kleihauer-Betke test as clinical indicator of transplacental bleed even in Rhesus-positive women.
* Anti-D for rhesus negative women after road accidents.
* Midwives are seen to have a key role in the education of women about car safety devices.They must be well informed.Simone Bajada is a specialist registrar in obstetrics and gynaecology. David W Pring is a consultant obstetrician and gynaecologist, both at the Department of Obstetrics and Gynaecology, York District Hospital, York.

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Original article written for MIDIRS by Simone Bajada and David Pring. © MIDIRS 2002.