Reduced fetal movements in pregnancy: systematic reviews of the evidence and a case-control study of perinatal risk factors and outcomes

Background: The presence of fetal movements (FMs) is regarded as an indicator of fetal wellbeing during pregnancy. Conversely, maternal perception of reduced fetal movements (RFM) is considered a potential sign of a fetus at risk of adverse perinatal outcomes, particularly stillbirth. Early detection of RFM is considered an opportunity for fetal health screening, thus current clinical guidance encourages women to contact the maternity hospital for any FM concerns. Preventing and reducing adverse outcomes can only be achieved through better detection and management of women with RFM. Pregnancy characteristics of women with RFM however vary across studies. Aim: The thesis aim was to present an investigation of perinatal risk factors for, and pregnancy, birth and neonatal outcomes associated with RFM in pregnancy. Methodology and Methods: A review of the existing literature was conducted to provide background information on FMs and RFM. A systematic review was also conducted to synthesise the evidence from non-randomised studies on perinatal risk factors for and pregnancy, birth and neonatal outcomes in women who presented with RFM. Subsequently, a case-control study, underpinned by a positivist philosophy, was chosen as the most appropriate research design to address the study aims and objectives in the context of maternity care in Ireland. Ethical approval was granted by the University and Hospital Research Ethics Committees. A prospective case-control study of women with a singleton pregnancy, presenting to the emergency department, of a large urban maternity hospital, with a primary complaint of RFM after 24 weeks’ gestation (cases) between 1 January -30 September 2020 were compared with women who did not have RFM during pregnancy (controls). To provide up to date contemporary evidence on perinatal risk factors for and outcomes associated with RFM, the systematic review was updated to include the findings of the prospective case-control study. Findings: The effectiveness of many strategies to raise awareness of FMs and improve detection of RFM remains inconclusive. Several maternal characteristics also impact on maternal perception of FMs, some of which can be classified as risk factors for RFM e.g., anterior placenta and obesity. Modifiable (smoking) and non-modifiable (ethnicity, anterior placenta, and abnormalities of amniotic fluid) risk factors for RFM were identified in the systematic review. Variation in the reporting of risk factors deemed prominent in contemporary maternity care was emphasised. The association between RFM and stillbirth was almost 4-fold at increased risk, while babies born small for gestational age (SGA) were nearly two-fold. The case-control study compared 850 women who presented with RFM with 1743 women who did not present with RFM during the study period. The rate of women attending with RFM has nearly doubled in the last two decades. Women with RFM, were more likely to be younger than 35 years, nulliparous, have a higher mean body mass index and have an anterior positioned placenta. Women with a history of pregnancy after loss, specifically recurrent miscarriages or neonatal death were also more likely to attend with RFM during pregnancy. In contrast to the findings of the systematic review, RFM was not found to be associated with stillbirth, however, was associated with babies born SGA. Consistent with numerous studies, women with RFM were more likely to have induction of labour, although emergency caesarean section was not associated when other factors were included in the analysis. The updated systematic review identified risk factors for RFM as nulliparity, women with anterior placenta, assisted conception, a medical history of psychiatric illness and a previous history of neonatal death. African Black ethnic groups were less likely to attend for RFM than Asian/Chinese women, including women aged 35 years and over. The risk of stillbirth associated with RFM is declining, though potentially only in cases where women have increased awareness of FMs and RFM and is dependent on the timing of assessment for RFM and subsequent clinical management. Conclusion: Knowledge of maternal characteristics associated with RFM could assist in identifying pregnancies at higher risk of adverse perinatal outcomes and aid decision making regarding need for further investigation when a woman presents with RFM during pregnancy. Contemporary evidence also signifies the groups of women that may require additional support through information and education on fetal movements. It also identifies that improvement in the detection of SGA during pregnancy is required.