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World Health

CH-1211 GENEVA 27

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Every Pregnancy Faces Risk (WHD 98.5)

Every year there are an estimated 200 million pregnancies in the world. Each one of these faces the chance of an adverse outcome for the mother and for the baby. While risks cannot be totally eliminated once pregnancy has begun, they can be reduced through effective, affordable, accessible and acceptable maternity care.

In theory, risk assessment is a logical tool for rationalising service delivery to ensure that those "in greatest need" receive special attention and care. In fact, however, it is becoming increasingly clear that a formal risk approach is problematic and may divert scarce resources away from the majority of women with poor pregnancy outcomes. In the absence of additional data demonstrating the effectiveness of risk screening, therefore, risk assessment should not be relied on as the basis for matching needs and care in maternity services.


Defining Maternal Risk

Maternal risk is defined as the probability of dying or experiencing serious injury as the result of pregnancy or childbirth.1 All pregnant women, by virtue of their pregnant status, face some level of maternal risk. Data suggest that around 40% of all pregnant women have some complication. About 15% of pregnant women need obstetric care to manage complications which are potentially life-threatening to mother or infant. Such complications are often sudden in onset and unpredictable.2

Although some sub-populations of pregnant women may experience a higher level of maternal risk than others, it is almost impossible to predict, on an individual basis, who will develop a life-threatening complication. It is therefore critical that all pregnant, labouring and recently delivered women have access to high quality essential obstetric services if and when the need arises.


Re-assessing Risk Assessment

Risk assessment tools usually involve using a list of risk factors and some form of scoring system to separate women into risk categories ­ typically "high risk" and "low risk" ­ using cut-off points or thresholds.3 Risk screening is usually conducted during antenatal care, and involves detecting early symptoms and predicting the likelihood of complications. The intention of risk assessment is to predict problems before they occur and so to take action.

A review conducted in 1992 for WHO's Maternal Health and Safe Motherhood Research Program found that the risk approach is not effective in ensuring the rational use of maternal health services or in preventing maternal deaths.4 The reasons for this include:

  • Many risk assessment systems rely on socio-demographic or physical characteristics such as education, age, parity and height, to classify women as "high" or "low" risk. However, these characteristics are not necessarily indicative of obstetric complications. In addition, depending on how the parameters are defined (e.g., age under 18, parity 4+), they can result in a large proportion of pregnant women being identified as high risk.

In fact, however, a large proportion of these women never develop complications (false positives), and a substantial proportion of the women who do develop complications are initially judged to be "low risk" (false negatives). In other words, the sensitivity, specificity, and positive predictive value of risk assessments using such characteristics are poor.1,5,6 Under- and over-diagnosing women "at risk" has serious implications both for women, who may not receive the services they need, and for health systems, which may spend scarce resources on unnecessary interventions.3

  • For risk assessment systems to be effective, individual risk factors need to be closely linked to and predictive of the outcomes of interest ­ in this case, maternal deaths and serious morbidity. Some risk factors are more closely linked to these outcomes, such as poor obstetric history (e.g. a history of obstructed labour) and conditions such as vaginal bleeding or malpresentation. However, these risk factors may not be relevant for all women, or may occur so close in time to the outcome of interest that there may not be an opportunity for effective intervention. Risk categories thus are more often based on clinical intuition than scientific study. Weights or scores assigned to individual factors for calculating risk levels are similarly unscientific.1,7
  • A key assumption of risk assessment strategies is that a specified risk (in this case, maternal risk) can actually be defined, and that individuals can be clearly separated into either high or low risk categories. Maternal risk, however, is not constant; a woman can move from low to high risk or vice versa throughout her pregnancy and the puerperium. She may also face different levels of risks with different pregnancies. Furthermore, it is not at all clear where along the risk continuum a low risk pregnancy becomes high risk.1,3
  • Even if risk screening were an effective tool to identify women who are likely to develop complications, many health systems would not be able to provide appropriate care, either because services and referral mechanisms are inadequate or because women themselves are unable to take appropriate action. Women are not passive recipients of risk labelling; their decisions not only take into account the advice of health care workers, but may also reflect financial difficulties, time constraints or their need to obtain permission from other family members.
  • The costs of inefficient risk assessment can be considerable. For women and their families, there are costs related to over-diagnosis (false positives), including direct costs of unnecessary treatment, opportunity costs for time spent seeking unnecessary services and the psychological burden of being labelled "high risk". The cost of missed diagnosis (false negatives) can be even more severe ­ missed treatment which can result in death. There are also costs to the health system: time spent learning and applying the risk assessment tool and overloading services with false positives.

The Role of Risk Assessment in Maternal Care

Certain sub-populations of pregnant women are at higher risk of obstetrical complications than others. However, as explained above, risk assessment systems are not able to identify accurately which women will experience negative outcomes, and as such are not likely to result in more effective or efficient service provision.1

Risk screening can even become a barrier to essential obstetric care for women experiencing complications. When a large proportion of "high risk" women do not develop complications and a substantial number of "low risk" women do, the credibility of the health worker is seriously compromised. As a result, referrals to appropriate medical care may be ignored.5,6

The health of low-risk women may also be compromised by such labelling. Women may be lulled into a false sense of security and fail to recognise or respond to complications when they do arise. Their health care providers may also miss early warning signs because of a general tendency to confuse low-risk with no-risk.5


What Can Be Done

Rather than focusing on classifying women as "high" or "low" risk, antenatal care should include the following functions (in addition to standard preventive and curative care):

  • Promoting and facilitating the entry of all women into the health care system by ensuring that services are provided as close as possible to where women live.
  • Ensuring continuity of care through high quality, integrated reproductive health services.
  • Improving women's overall well-being and reproductive health through the provision of prophylaxis (tetanus immunization, iron, etc.), as appropriate, as well as detection and treatment of existing pathologies (e.g. STDs) that contribute to poor reproductive health.
  • Education of women and their families about the risk of obstetric complications faced by all pregnant and postpartum women, and about the appropriate action should early warning signs be identified.
  • Early identification and appropriate management of obstetric complications during pregnancy, as well as appropriate care for women with special needs (adolescents, nullipara, etc).
  • Prompt referral of women with obstetric complications during pregnancy to appropriate medical care, as well as effective motivation of women and their families to agree with these referrals, and assistance to help them comply.

In order to significantly reduce maternal mortality, all pregnant, labouring and recently delivered women must have access to essential obstetric care should complications arise.6

  • At the household or village level, this means clean deliveries by personnel trained in midwifery; prompt recognition of complications and appropriate referrals; and community transportation schemes that enable women to reach services in a timely fashion, when (and if) the need arises.
  • Health centres and maternity homes should offer clean delivery by skilled personnel; prompt recognition of complications and appropriate referrals; and should be able to stabilise a woman experiencing complications until she can be safely transferred to the next level of care.
  • A functioning system of communication and transportation between all levels of the health system is essential for the appropriate referral and use of obstetric services.

Even with the best antenatal care, however, women will still die of obstetrical complications if appropriate services do not exist or if they are unable to access these services in a timely fashion.



1. B. Winikoff, "Maternal Risk". Paper presented at Berzelius Symposium, Stockholm, Sweden, 1991.

2. M.A. Koblinsky, et al., eds., The Health of Women: A Global Perspective. Westview Press, Oxford, 1993.

3. W. Graham, "Every Pregnancy Faces Risk". Presentation at Safe Motherhood Technical Consultation in Sri Lanka, 18-23 October 1997.

4. C. Rooney, "Antenatal care and maternal health: How Effective Is It? A review of the evidence" (WHO/MSM/92.4).World Health Organization, Geneva, 1992.

5. E.A.Yuster, "Rethinking the role of the risk approach and antenatal care in maternal mortality reduction". International Journal of Gynaecology and Obstetrics 50(2), 1995.

6. J.E. Rhodes, "Removing Risk from Safe Motherhood". International Journal of Gynaecology & Obstetrics 50(2), 1995.

7. "Guidelines for Monitoring the Availability and Use of Obstetric Services". UNICEF/ WHO/UNFPA, 1997.


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