The overlap between miscarriage and extreme preterm birth in a limited-resource setting on the Thailand-Myanmar border: a population cohort study

Abstract

Background : No universal demarcation of gestational age distinguishes miscarriage and stillbirth or extreme preterm birth (exPTB). This study provides a synopsis of outcome between 22 to <28 weeks gestation from a low resource setting. Methods : A retrospective record review of a population on the Thailand-Myanmar border was conducted. Outcomes were classified as miscarriage, late expulsion of products between 22 to < 28 weeks gestation with evidence of non-viability (mostly ultrasound absent fetal heart beat) prior to 22 weeks; or exPTB (stillbirth/live born) between 22 to < 28 weeks gestation when the fetus was viable at ≥22 weeks. Termination of pregnancy and gestational trophoblastic disease were excluded. Results : From 1995-2015, 80.9% (50,046/ 61,829) of registered women had a known pregnancy outcome, of whom 99.8% (49,931) had a known gestational age. Delivery between 22 to <28 weeks gestation included 0.9% (472/49,931) of pregnancies after removing 18 cases (3.8%) who met an exclusion criteria. Most pregnancies had an ultrasound: 72.5% (n=329/454); 43.6% (n=197) were classified as miscarriage and 56.4% (n=257) exPTB. Individual record review of miscarriages estimated that fetal death had occurred at a median of 16 weeks, despite late expulsion between 22 to <28 weeks. With available data (n=252, 5 missing) the proportion of stillbirth was 47.6% (n=120), congenital abnormality 10.5% (24/228, 29 missing) and neonatal death was 98.5% (128/131, 1 missing). Introduction of ultrasound was associated with a 2-times higher odds of classification of outcome as exPTB rather than miscarriage. Conclusion : In this low resource setting few (<1%) pregnancy outcomes occurred in the 22 to <28 weeks gestational window; four in ten were miscarriage (late expulsion) and neonatal mortality approached 100%. In the scale-up to preventable newborns deaths (at least initially) greater benefits will be obtained by focusing on the viable newborns of ≥ 28 weeks gestation.

High levels of pathological jaundice in the first 24 hours and neonatal hyperbilirubinaemia in an epidemiological cohort study on the Thailand-Myanmar border

“… a Pregnancy outcome before 28 weeks of gestation was considered as a miscarriage [ 28 ]. b Demographic characteristics of pregnant women not contacted or who declined were similar to that of pregnant women counselled and interested except for a higher proportion of smokers (13.1% (100/768) vs 9.9% (184/1860), p = 0.019).…”

Outcomes of preterm infants born with marginal viability in a University Hospital in Thailand

“…In addition, we are aware that the number of births at this particular gestational week may be underestimated because many hospitals in rural areas of Thailand consider ending of pregnancy at this gestation as a spontaneous abortion. A population cohort study of extremely preterm births on the Thailand‐Myanmar border showed that delivery between 22 and <28 weeks of gestation occurred in 0.9% (472/49931) and a neonatal mortality rate approached 100% …”

“…A population cohort study of extremely preterm births on the Thailand-Myanmar border showed that delivery between 22 and <28 weeks of gestation occurred in 0.9% (472/49931) and a neonatal mortality rate approached 100%. 19 A study of a survival rate to hospital discharge in a university hospital in Muscat, Oman, between 2006 and 2013 revealed that, of a total of 81 infants between 23 and 26 gestational weeks admitted to the NICU, the survival rate of infants born at 23 weeks' gestation was 12.5% compared to 33.3% and 72.4% of those born at 24 and 25 weeks' gestation, respectively. 20 In our study, infants born at 24 weeks' GA had an approximately 50-65% composite chance of death or survival with a major disability.…”

Burden of soil-transmitted helminth infection in pregnant refugees and migrants on the Thailand-Myanmar border: Results from a retrospective cohort

“…Stillbirth was defined as birth of a fetus with no signs of life, at a gestation of ≥28 +0 weeks. SMRUs definition for stillbirth follows that recommended by WHO for international comparison and the rationale for the miscarriage definition, which has no agreed international standard, is provided elsewhere [ 23 ]. Preterm birth (PTB) was defined as pregnancy outcome between 28 +0 and 37 +0 weeks of gestation; only cases with their first ANC contact before completion of 37 weeks of gestation were considered for this analysis.…”