Late preterm and early term: when to induce a growth restricted fetus? A population-based study

Abstract

Purpose: (1) Compare fetal and neonatal morbidity and mortality associated with induction of labor (IOL) versus expectant management (EM) in women with isolated fetal growth restriction (FGR) between 34^0/7 and 38^6/7 weeks; (2) Determine optimal gestational age for delivery of such fetuses.

Materials and methods: A retrospective population based cohort study of 2232 parturients with isolated FGR, including two groups: (1) IOL (n = 1428); 2) EM (n = 804).

Results: IOL group had a lower stillbirth and neonatal death rates (p = .042, p < .001), higher 1 and 5 min Apgar scores and a higher vaginal delivery rate compared to the EM group. In the late preterm period, EM was associated with increased rate of low 1 and 5 min Apgar scores, nonreassuring fetal heart rate tracing (NRFHR), stillbirth and neonatal death rate (p = .001, p = .039). In the early term cohort, EM was associated with a higher rate of NRFHR and low 1 min Apgar scores (p = .003, p = .002). IOL at 37 weeks protected from stillbirth but not from adverse composite neonatal outcomes.

Conclusions: IOL of FGR fetuses at 37 weeks had a protective effect against stillbirth. In addition, at late preterm, it is associated with lower rates of stillbirth, neonatal death, and NRFHR.

Keywords:

• Fetal growth restriction
• induction of labor
• expectant management
• late preterm
• early term
• perinatal mortality

Acknowledgements

The manuscript is the MPH thesis of Dr. Tehila Tsemach.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.