INTRODUCTION

Utero-placental insufficiency can lead to several obstetric complications, including hypertensive disorders of pregnancy (HDP) and fetal growth restriction (FGR). Utero-placental complications contribute significantly to maternal and neonatal morbidity and mortality in the short- and long-term^1-5. Unfortunately, no curative options besides delivery exist. Therefore, preventive strategies are of great importance. Low-dose aspirin is proven to reduce the risk of HDP and FGR in women at risk^6-8. The risk-reducing effect of aspirin on preterm preeclampsia (PE) by up to 62% has been reported⁹.

Nowadays, aspirin is widely used in pregnancy, but its risk-reducing effect has been studied for many years, initially with conflicting results¹⁰. The risk-reducing effect of aspirin on HDP and FGR was first demonstrated in 1985¹¹. The evidence that administration of aspirin in early pregnancy before 16 weeks of gestation is crucial for its risk-reducing effect, was a break-through in 2010¹². This insight resulted in publication of international guidelines about aspirin use during pregnancy^13-15. Aspirin was added to the Dutch national guideline of obstetricians and gynecologists in 2018¹⁶. Recently, bij de Weg et al.¹⁷ revealed improved implementation of aspirin use during pregnancy among Dutch consultant obstetricians after publication of the national guideline between 2016 and 2021. Altogether, it took nearly four decades from first evidence about aspirin use during pregnancy to confirmed implementation of aspirin use during pregnancy among consultant obstetricians.

For a complete insight in the implementation of aspirin, community midwives are to be involved. Dutch maternity care system is based on risk selection, and >90% of newly pregnant women have their initial appointment with a community midwife. Community midwives are independently practicing healthcare providers with responsibility for the care of low-risk pregnant women. Hence, these midwives are able to identify risk factors in early pregnancy. Since timely onset of aspirin administration early in pregnancy has the optimal effect in reducing adverse outcomes, it is important that community midwives have knowledge of aspirin and its effects. Current guidelines acknowledge multiple moderate risk factors for developing utero-placental insufficiency which may not necessarily require an input from a consultant obstetrician. So, women with an otherwise low-risk pregnancy, might still have an indication for aspirin in pregnancy^{13,15,16,18,19}. Examples are nulliparous with a family history of PE, women with obesity (body mass index >35 kg/m²) and a pregnancy interval >10 years, or women aged ≥40 years and pregnant after egg cell donation. The Royal Dutch Association of Midwives aimed to improve awareness of the benefit of aspirin use in pregnancy among community midwives through implementation of a module on their website concerning scientific summary about aspirin to reduce the risk of HDP²⁰. In addition, a Dutch information folder about aspirin use during pregnancy for pregnant women under community midwives’ care was created²¹. Dutch community midwives are competent to set the indication for aspirin use in pregnancy, but do not have the authority to make a prescription for aspirin. Therefore, referral to a general practitioner or consultant obstetrician who do have the authority to prescribe aspirin is necessary.

A survey about barriers and facilitators faced by midwives in the United Kingdom showed that conflicting views and deficits in resources hindered the implementation of aspirin²². A systematic review on counselling about aspirin revealed three categories predicting the success of implementation of aspirin: capability, motivation and opportunity²³.

In the present study, we investigated the implementation of aspirin in pregnancy in the community midwifery-led care in the Netherlands and its practical needs and issues.

METHODS

RESULTS

Regarding participants characteristics, the survey was completed by 47 community midwives. The estimated response rate was 1.8%, 47 out of approximately 2568 registered community midwife members of the Royal Dutch Association of Midwives in 2021. General characteristics of the participants are listed in Table 1.

Concerning the knowledge about aspirin use during pregnancy, 32 out of 47 (68.1%) midwives were familiar with the module about aspirin of the Royal Dutch Association of Midwives, and 14 (29.8%) midwives were familiar with the client folder. The details about advising about aspirin use during pregnancy are given in Table 2.

About prescribing aspirin, all participants had advised aspirin use during pregnancy at least once. Practical issues with obtaining prescriptions for aspirin were reported by 17 participants (36.2%). The majority of this group, 14 out of 17 participants, specified that general practitioners are unfamiliar with the effects of this drug in pregnancy and reluctant to sign prescriptions. Two out of 17 participants experienced logistic problems and costs to receive a prescription of the consultant obstetrician, and one stated that policies differ per hospital and therefore cause confusion.

A later start of aspirin usage than advised in the module (before 16 weeks of gestation) due to practical issues was mentioned by 11 out of 17 participants experiencing these practical issues. The delayed start of aspirin usage varied from 2% to 50% of the cases. Two participants reported that due to practical issues they sometimes ignore the indication for aspirin and did not provide referrals for prescriptions anymore: one in estimated 3%, and one in estimated 20% of the cases.

Various routes for prescribing aspirin were used (Table 3). The majority of the participants referred to the general practitioner for a prescription (n=19; 40.4%), followed by consultation with a consultant obstetrician (n=17; 36.2%), over the counter (‘children’s aspirin’; n=14; 29.8%) and by an obstetrician within multidisciplinary setting (without a consultation) (n=11; 23.4%). Five participants reported another route: consultation of the midwife with a consultant obstetrician by phone (no consultation of patient in hospital; n=3) or via internet (n=1), and over the counter (n=1). Around one-third preferred to get a prescription via the general practitioner, and one-quarter over the counter. Two participants preferred to have the authority to prescribe aspirin themselves.

Regarding possible indications for aspirin use during pregnancy, participants’ knowledge about indications for aspirin use during pregnancy of community midwives is listed in Table 4. History of preterm pre-eclampsia or HELLP syndrome was identified as a risk factor for developing utero-placental complications by 97.9% of the community midwives. Moderate risk factors in women with otherwise low-risk pregnancy were identified by >75% of the respondents.

Regarding the preferred source of obtaining information on aspirin use during pregnancy, e-learnings were selected most frequently (n=24), followed by extending the module about aspirin of the Royal Dutch Association of Midwives (n=5), providing a national website about the topic (n=5), regional contact person (n=1), and written information of other resources (n=1). Eight participants selected the option ‘Other’, six suggested to study the module more in detail, one suggested a regional folder, and one mentioned that aspirin indications are medical indications.

The great majority of the midwives (n=45; 95.7%) reported that the intake consultation of the pregnant women is sufficiently early in pregnancy for timely start of aspirin before 16 weeks and of ample duration to sufficiently inform pregnant women (n=42; 89.3%). Around two-thirds of the participants (n=30; 63.8%) checked the adherence of aspirin regularly or frequently and used the website of The Netherlands Pharmacovigilance Centre Lareb²⁵ as a source to explain safety of the drug in pregnancy (n=33; 70.2%). The majority of the participants (n=27; 57.8%) almost never checked side effects.

DISCUSSION

The main finding of this study is that community midwives considerable contribute to the implementation of aspirin use during pregnancy, since all participants advised aspirin in their practice. Moreover, the majority knew their professional association’s website module on aspirin advise, and demonstrated their knowledge by the considerable rates of identifying risk factors for utero-placental complications and indication for aspirin use during pregnancy. Practical issues for the community midwives concerning prescribing aspirin were mentioned by one-third of the participants.

A small proportion of the practicing community midwives in the Netherlands responded to our survey. Characteristics of the participants correspond with the overall population: mostly female gender, educated in the Netherlands or Belgium, and with a wide range on years of work experience. Most participants worked in the province Noord-Holland and in a city.

Two-thirds of the participants are familiar with the module about aspirin use during pregnancy of the Royal Dutch Association of Midwives. Early initiation of aspirin before 16 weeks of gestation reduces the risk of developing utero-placental complications¹². Therefore, adequate identification of risk factors by the healthcare professional where the majority of pregnant women start their check-ups is of great importance. The minority of the participants was familiar with the client folder, and about half of them handed the folder out to the pregnant women sometimes. bij de Weg et al.²⁶ previously investigated patients’ perspective on aspirin use during pregnancy, showing that the majority of women at risk preferred to be informed, both verbally and written. In 2020, Karunia et al.²⁷ showed that offering verbal and written education about pre-eclampsia and aspirin resulted in improved knowledge and medication adherence. Evidence on compliance rate and the risk-reducing effect of aspirin showed a trend to lower incidence of preterm pre-eclampsia with an aspirin adherence ≥90% in comparison to <90% (OR=0.24 vs OR=0.65, p=0.19)²⁸. Reducing adverse obstetric outcomes could be achieved by raising adherence rates through improving pregnant women’s knowledge by counselling with the client folder. Another factor to take into account is the influence of the media communicating about results of healthcare studies²⁹. Press releases might influence the decision making of pregnant women. Finally, pregnant women with low health literacy should receive additional support in participating in the shared-decision making process³⁰. Designing folders with pictograms could be helpful for this population.

Around one-third of the participants experienced practical issues with obtaining prescriptions for aspirin. The majority of this group described issues with receiving a prescription from general practitioners, mostly because of unfamiliarity of the general practitioner with this subject since it is not mentioned in the Dutch guidelines of general practitioners. Participants prefer to obtain a prescription through the general practitioner over the consultant obstetrician for practical reasons: more easily accessible; women can mostly just collect the prescription in contrast to having to visit the consultant obstetrician. Practical issues were previously identified in a national survey among midwives in the United Kingdom as barriers in implementation of aspirin in clinical practice²³.

Almost 60% of the participants instructed women to take their aspirin at nighttime. Participants who did not specify these instructions, responded that this is the responsibility of the prescribing doctor or dispensing pharmacist, or that they were unfamiliar with this advice. The client folder informs about preferred time, but does not describe the rationale behind it. Platelets have a circadian rhythm with a peak release in the late night and early morning³¹. To inhibit this peak, nighttime intake helps rapid absorption with time to maximal plasma levels of up to two hours. Thereby, a more stable platelet inhibition >24 hours was seen in the cardiovascular population in case of nighttime intake in comparison with morning intake³². Education about this topic might motivate an increasing number of community midwives to optimize instructions.

There is consensus about the advice to start aspirin before sixteen weeks of gestation and advocated by the Royal Dutch Association of Midwives, the national guideline of the Dutch Society of Obstetrics and Gynecology and the international guidelines^{13,15,16,18-20}. The beneficial effect of an early start of aspirin intake was reported by Bujold et al.¹². Aspirins risk-reducing effect is based on improvement of placentation, a process that takes place during the first and early second trimester³³. Also mentioned in guidelines, is the consensus to stop aspirin at 36 weeks of gestation^{13,15,16,18-20}. There is no scientific evidence for this advice; however, there seems to be a biologically plausible reason, based on the life span of platelets between seven to ten days and the term period of pregnancy starting from 37 weeks of gestation onwards. Low-dose aspirin usage during pregnancy might slightly increase the risk of postpartum hemorrhage, but evidence is of moderate quality^6,34. Timely discontinuation may decrease the risk of bleeding around labor and promote guidance of community midwives during labor in low-risk women. The fact that there is no contraindication for regional analgesia during the use of aspirin without other anticlotting medication, confirms the safety profile of aspirin³⁵.

The present study listed several possible indications for aspirin use during pregnancy; the highest identification rates were seen for the indications history of PE and HELLP syndrome. Lower rates were found for history of term pregnancy induced hypertension (PIH) and for FGR. Furthermore, this might be explained by the scientific evidence showing a stronger risk-reducing effect of aspirin on PE in comparison to term PIH and to FGR⁷. On the other hand, placenta-related complications occur more often at term and therefore justify the counselling about aspirin for consecutive pregnancies^13,18.

The present study revealed that community midwives will most frequently identify an indication for aspirin in case of a combination of two or more moderate risk factors. Reasonable identification rates (>75%) were found for combinations of nulliparity, advanced maternal age (≥40 years), long pregnancy interval (>10 years), obesity and a family history of PE. In 2016, Bartsch et al.³⁶ developed a list of clinical risk factors for caregivers to identify women at risk for PE. In their meta-analysis, these factors were also identified as risk factors for PE³⁶.

Half of the participants preferred e-learning to improve their knowledge about aspirin use during pregnancy. A Cochrane review compared the effect of e-learning with traditional learning methods in a mixed professional care givers population, showing a similar or slightly better effect of e-learning on long-term skills and knowledge and in patients outcomes³⁷.

Participants felt no need for an earlier or longer intake consultation to improve counselling about aspirin use during pregnancy. More than half of the participants checked for adherence. The growing caregivers’ awareness of the effect of aspirin adherence on clinical outcomes as demonstrated among gynaecologists¹⁷ might increase the number of caregivers addressing this topic. Vigilance among midwives concerning knowledge on and checking for side effects should be standardized, because experiencing complaints or side effects could negatively influence adherence.

CONCLUSIONS

The present pilot study shows that the participating community midwives adequately identified risk factors for developing utero-placental complications in women with otherwise low-risk pregnancy. This knowledge attributes to the significance of community midwives in contributing to the implementation of aspirin use during pregnancy. The finding that the most common practical issue was prescribing aspirin, should be evaluated whether authorization of community midwives can be facilitated in the near future. With this study, we extended the research of implementation of aspirin use during pregnancy among caregivers. The results of our pilot study could be used for further studies to improve implementation, in collaboration with pregnant women, patient organizations, midwives, general practitioners and consultant obstetricians.