Neonatal Outcomes Are Similar between Patients with Resolved and Those with Persistent Oligohydramnios

Abstract

Objective Oligohydramnios (defined as amniotic fluid volume < 5 cm or deepest vertical pocket < 2 cm) is regarded as an ominous finding on prenatal ultrasound. Amniotic fluid, however, is not static, and to date, there have been no studies comparing perinatal outcomes in patients who are diagnosed with oligohydramnios that resolves and those who have persistent oligohydramnios.

Study Design This is a secondary analysis of a National Institutes of Health–funded retrospective cohort study of singleton gestations delivered at a tertiary care hospital between 2002 and 2013 with mild hypertensive disorders and/or fetal growth restriction (FGR). Maternal characteristics, delivery, and neonatal information were abstracted by trained research nurses. Patients with a diagnosis of oligohydramnios were identified, and those with resolved versus persistent oligohydramnios at the time of delivery were compared. The primary outcome was a composite of neonatal resuscitation at delivery: administration of oxygen, bag–mask ventilation, continuous positive airway pressure, intubation, chest compression, or cardiac medication administration. Secondary outcomes included FGR, timing, and mode of delivery.

Results Of 527 women meeting study criteria, 42 had oligohydramnios that resolved prior to delivery, whereas 485 had persistent oligohydramnios. There were no significant differences in patient demographics between groups. The gestational age at diagnosis was significantly lower for patients with resolved versus persistent oligohydramnios (median: 33.0 [interquartile range, IQR: 29.1–35.9] vs. 38.0 [IQR: 36.4–39.3], p < 0.001). There was not a substantial difference in rate of neonatal resuscitation (41 vs. 32%, p = 0.31). Patients with resolved oligohydramnios were more likely to have developed FGR than those with persistent oligohydramnios (55 vs. 36%, p < 0.02). There were no significant differences for gestational age at delivery, birth weight, or neonatal intensive care unit admission.

Conclusion Patients whose oligohydramnios resolved were diagnosed earlier yet had similar rates of neonatal resuscitation but higher rates of FGR than those who had persistent oligohydramnios.

Key Points

• When diagnosed earlier in pregnancy, oligohydramnios was more likely to resolve prenatally.

• Patients who were diagnosed with oligohydramnios earlier in pregnancy had higher rates of FGR.

• There were no differences in the rates of the composite outcome of need for neonatal resuscitation when comparing those with resolved versus those with persistent oligohydramnios. No differences in composite neonatal morbidity were noted between those with resolved versus persistent oligohydramnios.

Keywords

fetal growth restriction - neonatal resuscitation - oligohydramnios

• References

• 1 Chamberlain PF, Manning FA, Morrison I, Harman CR, Lange IR. Ultrasound evaluation of amniotic fluid volume. I. The relationship of marginal and decreased amniotic fluid volumes to perinatal outcome. Am J Obstet Gynecol 1984; 150 (03) 245-249
• 2 Brzezinski-Sinai NA, Stavsky M, Rafaeli-Yehudai T. et al. Induction of labor in cases of late preterm isolated oligohydramnios: is it justified?. J Matern Fetal Neonatal Med 2019; 32 (14) 2271-2279
• 3 Phelan JP, Platt LD, Yeh SY, Broussard P, Paul RH. The role of ultrasound assessment of amniotic fluid volume in the management of the postdate pregnancy. Am J Obstet Gynecol 1985; 151 (03) 304-308
• 4 Locatelli A, Vergani P, Toso L, Verderio M, Pezzullo JC, Ghidini A. Perinatal outcome associated with oligohydramnios in uncomplicated term pregnancies. Arch Gynecol Obstet 2004; 269 (02) 130-133
• 5 Melamed N, Pardo J, Milstein R, Chen R, Hod M, Yogev Y. Perinatal outcome in pregnancies complicated by isolated oligohydramnios diagnosed before 37 weeks of gestation. Am J Obstet Gynecol 2011; 205 (03) 241.e1-241.e6
• 6 Petrozella LN, Dashe JS, McIntire DD, Leveno KJ. Clinical significance of borderline amniotic fluid index and oligohydramnios in preterm pregnancy. Obstet Gynecol 2011; 117 (2 Pt 1): 338-342
• 7 Chauhan SP, Scardo JA, Hendrix NW, Magann EF, Morrison JC. Accuracy of sonographically estimated fetal weight with and without oligohydramnios. A case-control study. J Reprod Med 1999; 44 (11) 969-973
• 8 Gumus II, Koktener A, Turhan NO. Perinatal outcomes of pregnancies with borderline amniotic fluid index. Arch Gynecol Obstet 2007; 276 (01) 17-19
• 9 Savitz DA, Danilack VA, Cochancela J, Hughes BL, Rouse DJ, Gutmann R. Health outcomes associated with clinician-initiated delivery for hypertensive disorders at 34–38 weeks' gestation. Epidemiology 2022; 33 (02) 260-268
• 10 Martins JG, Biggio JR, Abuhamad A. Society for Maternal-Fetal Medicine (SMFM). Electronic address: [e-mail]. Society for Maternal-Fetal Medicine consult series #52: diagnosis and management of fetal growth restriction: (Replaces Clinical Guideline Number 3, April 2012). Am J Obstet Gynecol 2020; 223 (04) B2-B17
• 11 Yang X, Meng T. Admission of full-term infants to the neonatal intensive care unit: a 9.5-year review in a tertiary teaching hospital. J Matern Fetal Neonatal Med 2020; 33 (17) 3003-3009
• 12 Bahia MLR, Velarde GC, Silva FCD, Araujo Jr E, Sa RAM. Adverse perinatal outcomes in fetuses with severe late-onset fetal growth restriction. J Matern Fetal Neonatal Med 2022; 35 (25) 8666-8672
• 13 Chauhan SP, Taylor M, Shields D, Parker D, Scardo JA, Magann EF. Intrauterine growth restriction and oligohydramnios among high-risk patients. Am J Perinatol 2007; 24 (04) 215-221