Management of Subsequent Pregnancy After an Unexplained Stillbirth
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Journal of Perinatology (2010) 30, 305–310 r 2010 Nature Publishing Group All rights reserved. 0743-8346/10 $32 www.nature.com/jp STATE-OF-THE-ART Management of subsequent pregnancy after an unexplained stillbirth SJ Robson1 and LR Leader2 1Department of Obstetrics and Gynaecology, Australian National University, Canberra, Australia and 2School of Women’s and Children’s Health, University of New South Wales, Royal Hospital for Women, Randwick, Australia they face in a subsequent pregnancy, as well as potential Purpose: To review the management of pregnancy after an unexplained management strategies to optimize future pregnancy outcomes.2–4 stillbirth. Unfortunately, as many as one-third of such cases remain Epidemiology: Approximately 1 in 200 pregnancies will end in ‘unexplained’ and unexplained stillbirth is now the commonest stillbirth, of which about one-third will remain unexplained. Unexplained single contributor to perinatal mortality. stillbirth is the largest single contributor to perinatal mortality. There is no evidence that extensive research efforts over the last Subsequent pregnancies do not appear to have an increased risk of two decades have yielded a reduction in the incidence of this 2,5 stillbirth, but are characterized by increased rates of intervention distressing outcome. Virtually all of the published literature is (induction of labor, elective cesarean section) and iatrogenic adverse concerned with population-based strategies for primary prevention outcomes (low birth weight, prematurity, emergency cesarean section and of unexplained stillbirth. However, the commonest situation in post-partum hemorrhage). which clinicians will find themselves is management of women in their next pregnancy after an unexpected unexplained stillbirth. Conclusions: There is no level-one evidence to guide management in Effective care of women in their next pregnancy after an this situation. Pre-pregnancy counseling is very important to detect and unexplained stillbirth presents major management challenges, and correct potential risk factors such as obesity, smoking and maternal there is no level-one evidence available to guide clinicians in this disease. As timely delivery is the mainstay of management, early accurate setting. Although the odds ratio for recurrence of stillbirths from all determination of gestational age is vital. There is controversy regarding causes is almost five,6 studies of pregnancy outcomes subsequent to the pattern of surveillance, but evidence exists only for ultrasound and not unexplained stillbirth have not reported any increase in the risk of for regular non-stress testing, nor formal fetal movement charting. There perinatal death.7–10 However, those studies found that pregnancy is an urgent need for more studies in this important area. after stillbirth is characterized by increased rates of induced labor, Journal of Perinatology (2010) 30, 305–310; doi:10.1038/jp.2009.133; elective and emergency cesarean section, preterm birth and low published online 24 September 2009 birth weight. These adverse outcomes might be at least partly the Keywords: pregnancy; unexplained stillbirth; management; review result of obstetricians having a low threshold for intervention. A study of the management plans in pregnancy after unexplained stillbirth revealed that obstetricians commonly offer induction of Introduction labor and elective cesarean delivery, sometimes as early as 36 11 More than three million babies are stillborn across the world each weeks, irrespective of any other obstetric considerations. In view year, the majority in developing countries.1 Even in developed of the obvious potential for iatrogenic prematurity and maternal nations stillbirth remains a common adverse outcome of complications with these interventions, it is important to minimize pregnancy, affecting about one in 200 pregnancies in countries the risk of another stillbirth while avoiding unnecessary such as the United States and Australia.2 In the majority of cases interventions. diligent investigation will reveal one or more likely causes for a fetal death. Accurate knowledge of the etiology of a stillbirth will Pre-pregnancy then allow the woman and her family to be counseled about risks Different classification systems for stillbirth are used by various Correspondence: Dr SJ Robson, Department of Obstetrics and Gynaecology, Australian population-based perinatal data collections around the world. It is National University, The Canberra Hospital, PO Box 11, Woden, ACT, 2600, Australia. likely that much of the reported geographical variation in the rates E-mail: [email protected] Received 22 February 2009; revised 5 July 2009; accepted 12 July 2009; published online 24 of unexplained stillbirth results from the use of different 12 September 2009 classification procedures. Many coding systems used to classify Pregnancy after unexplained stillbirth SJ Robson and LR Leader 306 stillbirths do not distinguish between cases where no cause of death for stillbirth.26 Obesity is notoriously difficult to manage, and many was found despite thorough investigation, and those where obstetricians feel inadequately prepared to supervise weight incomplete investigation made final diagnosis impossible.13 This normalization programs.27 Treatment of obesity is best managed in latter group, often referred to as ‘unexplored’ stillbirths, are likely a multidisciplinary setting and will take time, as optimal weight to represent a large proportion of unexplained stillbirths.14 loss is about 1 kg per week.28 The issue of importance for clinicians is that couples seeking The other modifiable risk factor for stillbirth is smoking. It pre-pregnancy counseling after ‘unexplained’ stillbirth, actually would be unusual to encounter a woman who is not aware that may have been incompletely investigated. Principles of the smoking is deleterious in pregnancy. Nonetheless, adverse investigation of stillbirth have been reviewed in detail elsewhere.3,4 outcomes in a previous pregnancy do not necessarily motivate It may be useful to describe a previous stillbirth as unexplained but women to cease smoking.29 Again, specialized smoking cessation low recurrence risk (that is, sufficient investigation was performed programs that include support groups and counsellors, combined to exclude all the causes of stillbirth known to be associated with a with the use of nicotine replacement therapies, are most likely to risk of recurrence), or unexplained but potentially recurrent (where succeed.30 a lack of information makes it impossible to tell what the risk of Many women will be highly motivated to try for another child recurrence is). after stillbirth, with studies showing that as many as half of all Faced with a woman for whom a previous stillbirth was bereaved couples become pregnant within 6 months.31 Timing of unexplained because of incomplete investigation, it is obviously the next pregnancy is important as women who conceive within 12 impossible to obtain information that would have been provided by months of a perinatal loss have higher rates of depression and a perinatal autopsy, karyotyping of the fetus or examination of the anxiety in their next pregnancy than women who conceive later.32 placenta and membranes. In this situation the next pregnancy is There is evidence that these emotional states can influence best considered ‘high risk’, and before the woman attempts pregnancy outcome: diagnosis and management of maternal pregnancy again maternal conditions associated with an increased anxiety and depression may reduce the risk of preterm birth and risk of adverse pregnancy outcomes should be tested for, including possibly other adverse pregnancy outcomes.33–36 In view of this, hypertension, thyroid and chronic renal disease. Other conditions formal assessment of the woman’s (and probably her partner’s) to be excluded include diabetes,15 inherited or acquired level of depression and anxiety to identify pathological grief thrombophilias,16,17 lupus,18 blood group antibodies and responses is worthwhile. Simple self-administered instruments such hyperhomocysteinemia.19 If diagnosed, these conditions should be as the Edinburgh Postnatal Depression Scale37 and the treated and stabilized. Most infectious events associated with Spielberger State-Trait Anxiety Inventory32 are readily available stillbirth are acute and hence unlikely to recur, but empirically it is and allow accurate assessment of women who might benefit from important to exclude chronic infectious conditions such as referral for further psychological assessment before embarking on toxoplasmosis, syphilis and possibly Chlamydia.20 There is some another pregnancy. It is important not to underestimate the effect evidence that chronic periodontal disease increases the risk of of a previous pregnancy loss, and even couples who appear to have adverse pregnancy outcomes,21 and evidence from animal models made a good emotional recovery should be offered counseling. suggests that these effects could include stillbirth.22 If there is any history suggestive of periodontal disease (typically bleeding from the gums with vigorous tooth brushing) then examination and management by a dentist is prudent. Early pregnancy A number of ‘demographic’ risk factors for stillbirth are difficult Many women who have had a previous unexplained stillbirth will or impossible to modify. These include low socioeconomic status first seek care once they are pregnant. One of the most important and increased maternal age.2 There is also some evidence