Singleton stillbirth : etiology, labor, aftercare, and subsequent pregnancy

Stillbirth is a devastating pregnancy complication, the causes of which are poorly known. Partly because of incomplete postmortem examinations, 10–50% of stillbirths are left unexplained. The overall probability of a normally proceeding delivery is high among pregnancies with stillbirth, although some complications, such as retained placenta and postpartum hemorrhage, may be more common. An empathetic approach and joint decision-making are key elements in stillbirth aftercare. Taking care of the parents’ mental well-being is essential, as approximately 50% of women become pregnant again within a year of stillbirth. The outcome of the subsequent pregnancy seems to be generally good, although recent studies have suggested an elevated risk for placenta-mediated complications. The risk for stillbirth recurrence after an unexplained cause is, however, understudied, and the evidence surrounding it is controversial. Retrospective studies (Studies I–III) and a questionnaire study (Study IV) were conducted at the Department of Obstetrics and Gynecology, Helsinki University Hospital, Finland. The retrospective cohort consisted of 214 antepartum singleton stillbirths at or after 22 gestational weeks between 2003 and 2015. In the study on the effectiveness of the postmortem examination protocol (I), all data were gathered from medical records, including postmortem examination results and death certificates. Causes of death were then classified into ten categories, and reevaluation of the postmortem examinations followed. In the study on delivery characteristics and complications (II), two age-adjusted controls giving singleton live births at the same institution in the same year were chosen from the Finnish Medical Birth Register. The delivery characteristics and pregnancy complications were compared between stillbirths and live births with and without adjusting for gestational age. In the study exploring subsequent pregnancy and delivery after stillbirth (III), the pregnancy outcomes of 154 members of the previous 214-woman cohort who had delivered again by the end of 2017 were compared to the outcomes of singleton pregnancies of parous women in Finland from the Finnish Medical Birth Register. The questionnaire survey (IV) was conducted between 2016 and 2020 among women with antepartum singleton stillbirth at or after 22 gestational weeks between 2016 and 2019. The questionnaire covered the following five major topics: stillbirth diagnosis, delivery, information on postmortem examinations, aftercare in the ward, and follow-up consultation. The cause of death, based on the systematic protocol of Helsinki University Hospital, was originally defined and reported as such to parents in 133 cases (62.1%). A reevaluation of the postmortem examination results revealed the cause of death in an additional 43 cases (20.1%). The cause of death in 15 cases (7.0%) was unknown due to incomplete investigations or because the results were not available for analysis. Only 23 cases (10.7%) remained truly unexplained. Placental insufficiency was the most common cause of death (56/214, 26.2%). Stillbirths occurring at or after 39 gestational weeks remained unexplained more often than stillbirths that had occurred earlier (24.1 vs. 8.6%, p = 0.02) (I). In Study II, labor induction was more common (86.0 vs. 22.0%, p < 0.001), and cesarean sections were less frequent (9.3 vs. 28.7%, p < 0.001) among pregnancies with stillbirth than in ones with live birth. The duration of labor was also shorter among these women (first stage 240.0 vs. 412.5 min, p < 0.001; second stage 8.0 vs. 15.0 min, p < 0.001). Although the rates of serious maternal complications were low, placental abruption was more common among the case women (15.0 vs. 0.9%; p < 0.001), and blood transfusions were needed more often (10.7 vs. 4.4%; p = 0.002). In Study III, the rates for adverse pregnancy outcomes were higher for preeclampsia (3.3 vs. 0.9%, p = 0.002), preterm birth (8.5 vs. 3.9%, p = 0.004), small-for-gestational-age newborns (7.8 vs. 2.2%, p < 0.001), and stillbirth (2.6 vs. 0.3%, p < 0.001) in women with previous stillbirth than in the Finnish parous background population. Four preterm recurrent stillbirths occurred. Labor induction was more common among women with previous stillbirth than in the reference group of parous women giving birth at the same institution (49.4 vs. 18.3%, p < 0.001). Mean birth weight was lower among the newborns of the case women (3274 ± 770 vs. 3491 ± 674 g, p < 0.001). During the questionnaire survey (IV), 119 letters were sent out, to which 57 of the mothers (47.9%) and 46 of their partners (38.7%) responded. Both mothers and their partners were satisfied with the support given during delivery and in the ward after delivery. However, counseling from social workers was less helpful, according to both groups (mothers 53.7%, partners 61.0%). The majority felt that the follow-up visit had been useful, although a significant proportion felt that it had increased their anxiety (25.9% and 14.0%, respectively). The partners rated their mood more highly than the mothers (p = 0.001). Open comments provided by the respondents revealed that the support they had received after discharge from the hospital was often insufficient. Also, despite otherwise good care, small and inconsiderate comments or actions could remain in the parents’ memories. This thesis concluded that the rate of unexplained stillbirth can be reduced by applying a standardized systematic postmortem examination protocol and that the interpretation of the results can be time-consuming and require specific orientation. In addition, it was found that the provision of better counseling would be beneficial. Moreover, the thesis identified that deliveries in pregnancies with stillbirth proceed well, often quicker than in pregnancies with live birth, and that the vast majority of mothers deliver vaginally. However, the risk for bleeding complications and postpartum interventions seems to be elevated. The overall probability of a favorable outcome in a subsequent pregnancy is high, although placenta-mediated pregnancy complications are more common than in the parous background population. Furthermore, our questionnaire study showed that the parents had received adequate care and support during their hospital stay and at their follow-up appointment after stillbirth. However, it is necessary to constantly train professionals in how to meet and guide parents who have experienced stillbirth. In addition, there is a need to create and implement a more structured, evidence-based protocol to support parents after discharge from the hospital. Our results may not be applicable globally, but the information they provide may prove useful when counseling parents who experience stillbirth in other high-income countries with low stillbirth rates and universally accessible maternity health care.