435 - Placental size and neonatal opioid withdrawal syndrome

Publication Number: 435.6088

Nana Matoba, Univeristy of California San Diego, La Jolla, CA, United States; Mana Parast, University of California, San Diego School of Medicine, La Jolla, CA, United States; Michelle Leff, University of California, San Diego School of Medicine, San Diego, CA, United States; Karen Mestan, UC San Diego/Rady Children's Hospital, La Jolla, CA, United States

Background: Neonatal opioid withdrawal syndrome (NOWS) is challenging to treat due to its variable symptom severity. At present, there is a critical need for innovative strategies to tailor treatment for NOWS accurately based on biological evidence. The placenta is a critical physiological interface between the mother and offspring, and may serve as a marker of differences in prenatal opioid exposure. To date, however, the relationship between placental characteristics and NOWS remains unclear.

Objective: To examine the association between placental size and NOWS severity.

Design/Methods: This is a retrospective and cross-sectional study of neonate born to women with prenatal opioid use at two University of California San Diego hospitals between 2018 and 2023. Placental pathology reports were obtained and linked to maternal and neonatal medical records. Neonatal clinical course was examined for timing of withdrawal onset, medications used for withdrawal, nutritional support and length of hospitalization. Maternal and neonatal characteristics were compared between categories of placental size: large- (>90th percentile), appropriate-, and small-( < 10th percentile) for gestational age using ANOVA.

Results: Among 80 placentas from opioid-exposed pregnancies, there were 12 SGA, 38 AGA, and 17 LGA placentas. Infants born to women with LGA placentas had higher rates of multiple (>2) drug exposure, need for medication to treat withdrawal, longer length of hospitalization, and higher Finnegan’s withdrawal scores. LGA placentas had the highest exposure to fentanyl (59.3%) compared to SGA (25.0%) and AGA (31.5%) placentas, as well as exposure to amphetamines (Table 1). Days on medication and timing of initiation of medications did not differ between placenta sizes (Figure 1). Type of medication varied between groups, with higher percentage of infants from SGA placentas requiring no medications (Figure 2).

Conclusion(s): Placental size appears to be associated with severity of NOWS. In particular, large sized placentas, possibly related to metabolism and function, may confer additional risk to NOWS severity.

Clinical characteristics by placental size
Table 1.pdf

NOWS course by placenta size
Figure 1.pdf

Medications used for NOWS by placenta size
Figure 2.pdf

Clinical characteristics by placental size
Table 1.pdf

NOWS course by placenta size
Figure 1.pdf

Medications used for NOWS by placenta size
Figure 2.pdf