Search results

The outreach yielded a response rate of 60% (n = 47) from 19 out of 27 EU member states. A third of these responses (n = 16) pointed towards their national transposition of the EU directive, providing no additional information. Another 11 documents were generalized on pregnancy legislation with limited information on chemical hazards. Next, five more documents provided detailed information on chemical hazards but contained limited or no information on reproductive health. Lastly, five information leaflets for specific occupations were received and two more were duplicates of other documents we received. These were excluded as they did not add information beyond the directive. An overview of the replies from the outreach to the OSHA focal points and ICOH national secretaries is presented in Supplementary file 1.

As shown in the PRISMA flow diagram in Fig. 1, 973 records were collected through the literature search, making for a combined 1,020 records including the outreach. Nine records met the inclusion and exclusion criteria: eight from outreach and one from the literature search.

Fig. 1

PRISMA flow diagram of search results and outreach

Five member states contributed documents that matched the inclusion criteria, and a sixth was added through the literature search. Table 2 provides descriptive information on the nine included documents.

Table 2 Included documents for the analysisThematic synthesis resultsDescriptive themes Descriptive themes on hazard identification and characterisation

Most guidelines recommend a broader perspective beyond the annexes of the Pregnant Workers Directive. They also acknowledge the challenges in identifying all hazards related to reproductive toxicity. To mitigate this, the guidelines advocate for the use of supplementary tools, such as checklists and information leaflets for specific professions, to help uncover additional hazards not explicitly covered by the directive.

The primary challenge in hazard characterization often arises from limited or unclear data on hazards to pregnancy, necessitating reliance on conclusions drawn from primary epidemiological, in-vitro, and animal studies. Knowledge on toxicokinetic mechanisms is emphasized in these guidelines, and frequently cited as a key to determine whether a specific chemical is hazardous. An overview of the specific findings and examples on the theme of hazard identification and characterisation can be found in Table 3.

Table 3 Descriptive themes on identification & characterization of hazards to pregnancy Descriptive themes on exposure assessment and risk assessment

The guidelines highlighted the need for including multiple exposure routes, emphasizing the role of biomonitoring as a solution to assess total exposure. However, challenges remain due to the difficulties in performing biomonitoring and exposure assessment, including the need for repeated evaluations and the complexity of interpreting data, e.g. relating to efficacy of personal protective equipment (PPE) and intermittent exposures.

Risk characterization for the general worker usually begins by the comparison of exposure data with occupational exposure limits (OELs). This knowledge enables practitioners to define risk levels and evaluate whether modifications of working conditions are needed. For pregnant workers, it is however crucial to understand the origin of and rationale behind OELs. Guidelines stress the need for higher certainty in risk characterization for pregnant workers, often reflected in the application of additional uncertainty factors, such as using 10% of the conventional OEL for certain groups of substances. General principles of risk characterization are emphasized, particularly the notion that exposure is necessary for a hazard to pose a risk for pregnant workers. Table 4 provides further examples of these principles.

Table 4 Descriptive themes on exposure assessment & risk characterisation Descriptive themes on risk management

Most guidelines emphasize that control of exposures in the working environment should prioritize the higher tiers in the prevention hierarchy, such as elimination, substitution and engineering control, before implementing individual measures for pregnant workers. Preventive maternity leave should be considered only as a last resort when no other feasible solutions exist. Specific attention is given to the use of PPE for maternity protection, with a consensus that PPE should generally be avoided for pregnant workers due to the potential for additional risks and its unreliability in reducing exposure.

The guidelines stress the importance of a proactive approach in several areas. First, they emphasize the need for a clear, pre-established plan with a series of actions that are triggered upon the notification of the pregnancy by the worker to the employer. Second, they call for proactive exposure assessments, where data is collected in advance to facilitate faster and more informed decisions when a worker reports her pregnancy. Lastly, all workers should be proactively informed about procedures in the case of pregnancy, as this can speed up notification of the employer and thereby reduce the likelihood of adverse outcomes. Measures must be implemented with caution to avoid causing physical or psychological strain on pregnant workers, such as increased respiratory effort from respirator use or stress caused by having to perform tasks the worker is not trained for. Table 5 summarizes the contents of the analysed documents with regards to risk management.

Table 5 Descriptive themes on risk managementAnalytical themes

Two distinct analytical themes were found, both reflecting a fundamental need in evaluation of the risks posed by chemical agents to pregnant women. Below the identified themes are described, reflecting the need for a broad perspective when assessing chemical risks for reproductive health and the increased need for certainty in this assessment, with examples from the analysed documents.

Theme 1: need for a broad perspective

The analysed documents suggest the need for a comprehensive approach in terms of 1) the range of hazardous substances that should be considered (beyond those classified as reproductive toxicants), 2) the potential for multiple routes of as well as accidental exposures, 3) inclusion of the period before a worker is known to be pregnant in the risk assessment and risk management process, and 4) consideration of the potential adverse socio-economic consequences of maternity protection policies.

The EU Pregnant Workers Directive provides a list of substances and working conditions that must be evaluated or are prohibited for pregnant women. It is specifically stated that the list is non-exhaustive. Several guidelines indicate additional substance groups that should be considered. For example, many solvents are not included in the list provided by the directive, even though their harmonised hazard phrases are often of concern for the unborn child. An overview of these substance groups mentioned in the guidelines, collated through analysis of the relevant codes on risk identification, can be found in Table 6.

Table 6 Overview of substance groups mentioned in guidance documents that do not directly fall under Annex I and II of the pregnant workers directive [6]

…account must be taken of volatile chemicals such as solvents, monomers and amines, but also slowly evaporating chemicals such as auxiliary solvents, coalescing agents and plasticizers [16].

Acute toxicity, while not mentioned in the annexes of the Pregnant Workers Directive, was sometimes included in the list of hazard phrases substances should be screened for. Specifically, acute toxicity was included when it was classified as fatal (H300, H310, H330) or toxic (H301, H311, H331).

Activities or working conditions for pregnant women are generally not permitted if they are (or could be) exposed to hazardous substances that are classified under the CLP Regulation as… Acutely toxic according to category 1, 2 or 3 (H300, H310, H330, H301, H311, H331) [20].

When evaluating exposure, it is essential to adopt a comprehensive approach that considers all potential routes of exposure. This involves application of a combination of biomonitoring and environmental measurements to assess the total exposure, as well as consideration of the possibility of accidental or unintentional exposure. In the latter case, the effectiveness of control measures should be assessed. If there is a reasonable chance of unintentional exposure to a substance known to be toxic to reproduction, it is crucial to take this into account when determining the appropriate protective measures.

The injection or infusion of cytotoxic agents carries the risk of exposure through accidental leakage or splashes. Pregnant workers should not perform these tasks unless a closed system is used that has been shown to effectively prevent leakage of the cytotoxic solution outside the system [17].

The examined guidelines emphasise the importance of a proactive evaluation of all workplaces for reprotoxic hazards. This proactive approach is crucial because the first trimester is a period that is vulnerable to many chemical exposures, and at the same time, it is during this period the worker becomes aware of the pregnancy, i.e. before any protective measures are implemented. A proactive approach which extends to the time period before the conception, is especially needed in case of exposure to agents that accumulate in the worker’s body, such as lead and aluminium.

To prevent aluminium accumulation in the body, pregnant women should aim to keep exposure below the reference level [for urinary aluminium]. Since aluminium is a highly accumulative agent, it is important to detect potential accumulation early and address the exposure well in advance, when planning a pregnancy [17].

Finally, this broad perspective can also be extended to the prevention of unexpected negative consequences of maternity protection policies. For instance, work adaptations should align with the worker’s skills and needs, not to create frustration or psychological strain. Additionally, it is essential to ensure that the implemented measures do not adversely affect the professional development of pregnant workers or lead to discrimination at the professional level.

The focus here is on ensuring that women are not disadvantaged in their professional lives due to pregnancy and breastfeeding and that women’s right to make self-determined decisions about their employment is not violated. This improves women’s opportunities and strengthens their rights to continue working during pregnancy and breastfeeding without compromising their health and that of their children [20].

Theme 2: need for certainty

The importance of ensuring a high level of certainty when dealing with chemical substances during pregnancy, along with the challenges that this entails, are frequently highlighted in the analysed documents for all phases of the risk assessment and management process.

Identifying all potential hazards is the initial step in risk assessment. However, this is not always a straightforward task. Unreliability of safety data sheets can create an obstacle to a comprehensive hazard identification. Also, identifying reprotoxic process-generated substances, such as certain metal fumes/dusts or combustion products, can be challenging. Moreover, exposure to chemical mixtures can introduce additional challenges for the risk assessment process because the joint reprotoxic effects of many mixtures remain unknown.

Occupational exposure often involves the presence of a combination of several substances, and in these cases, it is not always possible to know the consequences of the interactions between the different substances and the possible synergistic effects that the chemical mixtures can produce [22].

To ensure the safety of pregnant workers in potentially hazardous environments, accurate exposure assessments are indispensable, considering all possible exposure routes. While biomonitoring is frequently regarded as a valuable tool because it considers all of these routes, practical and methodological challenges frequently hinder its implementation. For example, when workers are exposed to solvent mixtures often not all constituents of the mixture can be monitored through biological measurements. Nevertheless, in the exposure assessment also the exposure to the unmeasured constituents has to be taken into account.

When drawing conclusions about total exposure based on biological exposure measurements, the evaluation must consider the total exposure caused by the solvent mixture used. This means that the effects of constituents that cannot be measured in a biological sample must also be taken into account [17].

Characterising risk can be challenging, even when exposure can be reliably determined, because it is often difficult to discern whether the exposure level is safe. Occupational Exposure Limits (OELs) do not always take adverse reproductive effects into account, particularly in case of older limit values or newly introduced chemicals. The inability to determine, with certainty, whether a particular limit value is protective against reproductive effects adds to the level of uncertainty.

Currently, occupational exposure limit values only consider the effects on reproduction when the product has been tested for this effect. For the limit values established in previous years, it is not certain that this effect has been considered. Hence the need for a safety factor justified by the severity of the effect on foetal development [18].

The need for certainty becomes apparent once more in choosing the right risk management strategy. PPE is typically viewed as the “last line of defence” for managing risks in the protection hierarchy. However, during pregnancy, this is taken a step further, as PPE is deemed too unreliable and therefore not considered an option.

Since personal protective equipment never provides complete protection, tasks in which exposure and risks remain high despite other risk management measures should not be carried out by pregnant workers [17].