Maternal and fetal risk factors for stillbirth: population based study

Gardosi et al(1) reconfirm the need for early antenatal detection to reduce unrecognised fetal growth restriction. Did the authors findings also correlate with those of other studies in which stillbirth risk rises with increasing gestational age?(2) It would be interesting to know specifically, how many stillbirths occurred at 38, 39, 40, 41 and 42+ weeks’ gestation, and whether any respective maternal or fetal risk factors were identified? This information is potentially very important in the context of delivery mode decision-making, particularly when spontaneous labour does not occur. There are essentially three choices: wait for spontaneous labour, schedule induction or schedule a caesarean. An individual’s perception of risk and any delivery preference may influence this decision, and so will any identifiable risk factors. My concern is that women are not being given ALL the information available to help make this decision.

In 2006, U.S. researchers found a significant increase in the stillbirth rate after 39 weeks’ gestation, and estimated that timely delivery could prevent two deaths in every 1000 living fetuses, the equivalent of 6,000 deaths annually. Hankins et al(3) called it “an impact that far exceeds any other strategy implemented for stillbirth reduction thus far.” In 2009, Canadian researchers reported a decrease in life-threatening injuries to babies in a breech cesarean group, despite comparing these with cephalic presenting singletons in ‘healthy, first-time mothers’ (fewer mothers died in the cesarean group too).(4) And in 2010, in a study of nine Asian countries, the neonatal mortality rate was lowest with planned cesareans, as were rates of severe asphyxia and palsy.(5)

Yet in the UK, when stillbirth prevention is discussed, there often seems to be a reluctance to even mention the word ‘caesarean’. For example, in a crucially important stillbirth report last January (submitted for debate in Parliament), the word is notably absent,(6) and in a campaign article last November, a possible euphemism is the closest we get: “Those which happen near the end of pregnancy (about 30%) are potentially the most preventable, if only the baby could be delivered in time.”(7)

Unfortunately, the word ‘caesarean’ has become synonymous with ‘controversial’, and so research and maternity strategies are often framed in the context of a ‘caesarean epidemic’. This is largely due to the 1985 World Health Organization recommendation of a 15% threshold, and despite the WHO’s clarification in 2009 that there is in fact “no empirical evidence” for a caesarean rate threshold in any setting (“an optimum rate is unknown”),(8) the 15% legacy continues to feed an assumption that ‘lowering caesarean rates’ is synonymous with ‘improved health outcomes’ for mothers and babies.

Evidently, planned caesareans are not a panacea for reducing stillbirth rates in all pregnant women with known risk factors, and there are risks besides stillbirth that need to be considered, but they do deserve recognition as a valued element in any overall preventative strategy, and women should be informed of different birth risks and benefits equally.

Just this month, RCOG proposed induction at 39 weeks’ gestation for women aged ≥40 years to reduce the stillbirth risk, but made no reference to planned caesarean. Instead, “improved perinatal outcomes generally without increasing the caesarean section rate” was cited.(9) Also ironically, women who request a caesarean in the UK are frequently advised of the risk of subsequent stillbirth, even though the findings of a 2003 study were later disputed by at least three others.(10)

We are some way from ensuring balance in the information women are given, but it’s important to recognize that this is not just about informed ‘choice’ or birth autonomy. In the context of stillbirth and perinatal mortality, if planned caesareans remain taboo, it can be a matter of life or death.

References
1) Gardosi J, Madurasinghe V, Williams M, Malik A, Francis A. Maternal and fetal risk factors for stillbirth: population based study. BMJ 2013; 346: 1108
2) *Tim A Bruckner, Yvonne W Cheng, and Aaron B Caughey, “Increased neonatal mortality among normal-weight births beyond 41 weeks of gestation in California,” American Journal of Obstetrics and Gynecology 199, no. 4 (October 2008): 421.e1-7 *Yudkin PL, Wood L, Redman CW. Risk of unexplained stillbirth at different gestational ages. Lancet. 1987;1:1192 – 4.*Fretts RC, Elkin EB, Myers ER, Heffner LJ. Should older women have antepartum testing to prevent unexplained stillbirth? Obstet Gynecol. 2004;104:56 – 64. *Nohr EA, Bech BH, Davies MJ, Frydenberg M, Henriksen TB, Olsen J. Prepregnancy obesity and fetal death: a study within the Danish National Birth Cohort. Obstet Gynecol. 2005;106:250 – 9
3) Gary D V Hankins, Shannon M Clark, and Mary B Munn, “Cesarean section on request at 39 weeks: impact on shoulder dystocia, fetal trauma, neonatal encephalopathy, and intrauterine fetal demise,” Seminars in Perinatology 30, no. 5 (October 2006): 276-287.
4) Leanne S Dahlgren et al., “Caesarean section on maternal request: risks and benefits in healthy nulliparous women and their infants,” Journal of Obstetrics and Gynaecology Canada: JOGC = Journal D'obstétrique Et Gynécologie Du Canada: JOGC 31, no. 9 (September 2009): 808-817.
5) Virasakdi Chongsuvivatwong et al., “Maternal and fetal mortality and complications associated with cesarean section deliveries in teaching hospitals in Asia,” The Journal of Obstetrics and Gynaecology Research 36, no. 1 (February 2010): 45-51.
6) January 2012 Preventing Babies’ Deaths what needs to be done, SANDS http://www.appg-maternity.org.uk/resources/Sands+Presentation.pdf
7) November 27, 2012 Stillbirth should be tackled as cot-death syndrome once was, Janet Scott (SANDS), guardian.co.uk http://www.guardian.co.uk/commentisfree/2012/nov/27/stillbirth-needs-to-...
8) Monitoring Emergency Obstetric Care: a handbook. World Health Organization 2009 ISBN 978 92 4 154773 4
9) February 1, 2013 RCOG release: Induction of labour in older mothers may reduce risk of stillbirth, say experts http://www.rcog.org.uk/news/rcog-release-induction-labour-older-mothers-...
10) *Gordon C S Smith, Jill P Pell, and Richard Dobbie, “Caesarean section and risk of unexplained stillbirth in subsequent pregnancy,” Lancet 362, no. 9398 (November 29, 2003): 1779-1784. *S L Wood et al., “The risk of unexplained antepartum stillbirth in second pregnancies following caesarean section in the first pregnancy,” BJOG: An International Journal of Obstetrics and Gynaecology 115, no. 6 (May 2008): 726-731. *R Gray et al., “Caesarean delivery and risk of stillbirth in subsequent pregnancy: a retrospective cohort study in an English population,” BJOG: An International Journal of Obstetrics and Gynaecology 114, no. 3 (March 2007): 264-270. *Mert O Bahtiyar et al., “Prior cesarean delivery is not associated with an increased risk of stillbirth in a subsequent pregnancy: analysis of U.S. perinatal mortality data, 1995-1997,” American Journal of Obstetrics and Gynecology 195, no. 5 (November 2006): 1373-1378