Optimal Timing of Delivery in Small for Gestational Age Fetuses Near Term: A National Cohort Study

Abstract

Objective Our aim was to study the competing risks of antepartum versus intrapartum/neonatal death in small for gestational age (SGA) and non-SGA fetuses.

Study Design We performed a national cohort study using all singletons delivered between 36 and 42^6/7 weeks without hypertension, preeclampsia, diabetes, congenital anomalies, or noncephalic presentation from the Netherlands Perinatal Registry (1999–2007). The resultant cohort was divided in three groups based on birth weight by gestational age (SGA < P5 group, 61,021 deliveries; SGA P5–10 group, 58,902 deliveries; non-SGA group 1,168,523 deliveries). We compared the mortality risk of delivery with expectant management.

Results Delivery was associated with more mortality than expectant management for 1 week from 39 weeks onward in the non-SGA group (relative risk [RR], 1.26; 95% confidence interval [CI], 1.05–1.50). For the SGA < P5, expectant management for 1 more week was associated with more mortality from 38 weeks onward although this only reached statistical significance from 40 weeks onward (RR, 2.46; 95% CI, 1.80–3.36).

Conclusion At 36 and 37 weeks, delivery is associated with a higher risk of mortality in SGA < P5 fetuses than expectant management. Delivery of SGA < P5 fetuses at 38 and 39 weeks is associated with the best perinatal outcome whereas for non-SGA fetuses this is at 39 to 40 weeks.

Keywords

small for gestational age - optimal timing delivery - antepartum death - neonatal death

• References

• 1 Gardosi J, Mul T, Mongelli M, Fagan D. Analysis of birthweight and gestational age in antepartum stillbirths. Br J Obstet Gynaecol 1998; 105 (5) 524-530
• 2 Pilliod RA, Cheng YW, Snowden JM, Doss AE, Caughey AB. The risk of intrauterine fetal death in the small-for-gestational-age fetus. Am J Obstet Gynecol 2012; 207 (4) e1-e6
• 3 Stoknes M, Andersen GL, Dahlseng MO , et al. Cerebral palsy and neonatal death in term singletons born small for gestational age. Pediatrics 2012; 130 (6) e1629-e1635
• 4 McIntire DD, Bloom SL, Casey BM, Leveno KJ. Birth weight in relation to morbidity and mortality among newborn infants. N Engl J Med 1999; 340 (16) 1234-1238
• 5 Clausson B, Gardosi J, Francis A, Cnattingius S. Perinatal outcome in SGA births defined by customised versus population-based birthweight standards. BJOG 2001; 108 (8) 830-834
• 6 Boers KE, Vijgen SM, Bijlenga D , et al; DIGITAT study group. Induction versus expectant monitoring for intrauterine growth restriction at term: randomised equivalence trial (DIGITAT). BMJ 2010; 341: c7087
• 7 The Netherlands Perinatal Registry Web site. Available at: http://www.perinatreg.nl/ 2012 . Last accessed on December 12, 2013
• 8 Méray N, Reitsma JB, Ravelli AC, Bonsel GJ. Probabilistic record linkage is a valid and transparent tool to combine databases without a patient identification number. J Clin Epidemiol 2007; 60 (9) 883-891
• 9 Tromp M, Ravelli AC, Méray N, Reitsma JB, Bonsel GJ. An efficient validation method of probabilistic record linkage including readmissions and twins. Methods Inf Med 2008; 47 (4) 356-363
• 10 Visser GH, Eilers PH, Elferink-Stinkens PM, Merkus HM, Wit JM. New Dutch reference curves for birthweight by gestational age. Early Hum Dev 2009; 85 (12) 737-744
• 11 Alberman E, Blatchley N, Botting B, Schuman J, Dunn A. Medical causes on stillbirth certificates in England and Wales: distribution and results of hierarchical classifications tested by the Office for National Statistics. Br J Obstet Gynaecol 1997; 104 (9) 1043-1049
• 12 Stubblefield PG, Berek JS. Perinatal mortality in term and post-term births. Obstet Gynecol 1980; 56 (6) 676-682
• 13 Joseph KS. The natural history of pregnancy: diseases of early and late gestation. BJOG 2011; 118 (13) 1617-1629
• 14 Smith GC. Life-table analysis of the risk of perinatal death at term and post term in singleton pregnancies. Am J Obstet Gynecol 2001; 184 (3) 489-496
• 15 Smith GC. Estimating risks of perinatal death. Am J Obstet Gynecol 2005; 192 (1) 17-22
• 16 Rosenstein MG, Cheng YW, Snowden JM, Nicholson JM, Caughey AB. Risk of stillbirth and infant death stratified by gestational age. Obstet Gynecol 2012; 120 (1) 76-82
• 17 Trudell AS, Cahill AG, Tuuli MG, Macones GA, Odibo AO. Risk of stillbirth after 37 weeks in pregnancies complicated by small-for-gestational-age fetuses. Am J Obstet Gynecol 2013; 208 (5) e1-e7
• 18 Verlijsdonk JW, Winkens B, Boers K, Scherjon S, Roumen F. Suspected versus non-suspected small-for-gestational age fetuses at term: perinatal outcomes. J Matern Fetal Neonatal Med 2012; 25 (7) 938-943
• 19 Boers KE, van Wyk L, van der Post JA , et al; DIGITAT Study Group. Neonatal morbidity after induction vs expectant monitoring in intrauterine growth restriction at term: a subanalysis of the DIGITAT RCT. Am J Obstet Gynecol 2012; 206 (4) e1-e7
• 20 Clinical Trials. Available at: https://clinicaltrials.gov/ . Last accessed on December 12, 2013