Rebound hyperkalemia after cessation of ritodrine in a parturient undergoing cesarean section

Neonatal hyperkalemia associated with maternal ritodrine: A retrospective study

BACKGROUND

We recently reported on a late preterm infant born at 36 weeks' gestation with serious arrhythmia due to hyperkalemia associated with long-term maternal ritodrine administration. It is unknown whether ritodrine alone increases the risk of neonatal hyperkalemia in infants born at 34-36 weeks' gestation.

METHODS

This single-center, retrospective, cohort study enrolled late preterm infants (34-36 gestational weeks) born between 2004 and 2018. Cases with maternal magnesium sulfate use were not sufficient for statistical analysis and so were excluded from the study. Risk factors for the occurrence of hyperkalemia were determined based on clinical relevance and previous reports.

RESULTS

In all, 212 late preterm infants with maternal ritodrine use and 400 infants without tocolysis were included in the study. Neonatal hyperkalemia occurred in 5.7% (12/212) in the ritodrine group and 1.8% (7/400) in the control group. The risk of neonatal hyperkalemia was significantly increased by maternal ritodrine administration with a crude odds ratio (OR) of 3.37 (95% confidence interval [CI]: 1.30-8.69; p < 0.01) and an adjusted OR of 3.71 (95% CI: 1.41-9.74; p < 0.01) on multivariable analysis. Long-term tocolysis (≥28 days) with ritodrine increased the risk of neonatal hyperkalemia with 9.3% (11/118) of infants developing hyperkalemia (adjusted OR 4.86; 95% CI: 1.59-14.83; p < 0.01). Neonatal hyperkalemia was not found within 2 weeks of ritodrine administration.

CONCLUSION

This research suggests that late preterm infants born after long-term ritodrine administration are at risk of neonatal hyperkalemia and require special attention.

Antenatal mgnesium sulfate and ritodrine increased potassium levels in preterm infants: A cohort study

BACKGROUND

Ritodrine and magnesium sulfate are administered to prevent preterm labor. Magnesium sulfate is also administered to prevent preeclampsia. These drugs have been reported to increase potassium levels in pregnant women and neonates. The aim of this study was to investigate the relationship between potassium levels in preterm infants and antenatal treatment.

METHODS

This prospective cohort study was conducted at Saiseikai Suita Hospital. Preterm infants born at <35 weeks' gestation between October 2012 and September 2014 were recruited and divided into four groups based on the antenatal treatment their mothers received. Serum and urine electrolyte levels at birth and serum potassium levels 1 day after birth were measured.

RESULTS

The mothers of 16 infants received no antenatal treatment (condition C); the mothers of 29 infants received antenatal ritodrine (R); the mothers of seven infants received magnesium sulfate (M); and the mothers of 15 infants received both magnesium sulfate and ritodrine (M + R). At birth, potassium levels were similar among the four groups. However, potassium levels a day after birth were significantly higher in the M + R group than in the other groups: median (min.-max.) mEq/L 4.8 (3.8-6.2), 4.8 (3.6-6.0), and 4.4 (3.8-5.9) vs. 5.8 (4.9-7.2), in the C, R, and M groups versus the M + R group, respectively (P < 0.01). Significantly more infants in the M + R group exhibited a fractional excretion of potassium of <10% compared with those in the other groups.

CONCLUSION

The increased potassium levels we observe in preterm infants of mothers who received antenatal magnesium sulfate and ritodrine administration on postnatal day 1 warrant monitoring by neonatologists.

Neonatal rebound hyperkalemia associated with ritodrine alone: a case report

BACKGROUND

Betamimetics have been used for tocolysis extensively in the past, and one of them, ritodrine is widely used in Japan. Various adverse events have been reported for this agent, including newborn hypoglycemia and hypokalemia, as well as maternal hypokalemia and rebound hyperkalemia; however, cases of neonatal rebound hyperkalemia are not described in the literature.

CASE PRESENTATION

A male infant born at 36 weeks of gestation by cesarean section at a local maternity clinic suddenly entered cardiopulmonary arrest with ventricular tachycardia and fibrillation due to hyperkalemia (K+, 8.7 mmol/L). No monitoring, examination of blood electrolyte levels, or infusions had been performed prior to this event. Maternal infusion of ritodrine (maximum dose, 170 μg/min) had been performed for 7 weeks prior to cesarean section. After resuscitation combined with calcium gluconate, the infant died at 4 months old due to serious respiratory failure accompanied by acute lung injury following shock. No cause of hyperkalemia other than rebound hyperkalemia associated with ritodrine was identified.

CONCLUSIONS

This case report serves as a warning regarding the potential risk of neonatal rebound hyperkalemia in association with maternal long-term ritodrine administration.

Efficacy of allylestrenol combined with ritodrine on threatened premature labor and its influence on inflammatory factors in peripheral blood

Efficacy of allylestrenol combined with ritodrine on threatened premature labor (TPTL) and its influence on inflammatory factors in peripheral blood were investigated. A total of 206 cases of TPTL patients from 2014 to 2016 were collected in Zhongshan Hospital Affiliated to Fudan University, and 106 cases were treated with allylestrenol combined with ritodrine as a research group and 100 cases were treated with allylestrenol combined with magnesium sulfate as a control group. General information of patients was collected, and changes in the expression levels of IL-17, IL-10 and IL-6 were detected by enzyme-linked immunosorbent assay. Prolonged pregnancy time, success rate of fetal protection and average delivery time of patients were recorded. The adverse pregnancy conditions were compared, including the Apgar score of newborns, birth weight and adverse conditions, and postpartum hemorrhage volume and postpartum hospital stays in the two groups were recorded. Prolonged pregnancy time, success rate of fetal protection and average delivery time in the research group were significantly higher than those in the control group (P<0.05). After treatment, the levels of IL-17, IL-10 and IL-6 in serum of the two groups were significantly lower than those before treatment (P<0.05), and were significantly lower in the research group than in the control group (P<0.05). The average neonatal weight and Apgar score in the research group were significantly better than those in the control group (P<0.05). Postpartum hemorrhage, postpartum hospital stays and incidence rate of toxic side effects, neonatal death, malformation and asphyxia in the research group were significantly lower than those in the control group (P<0.05). Allylestrenol combined with ritodrine can significantly reduce the expression levels of IL-17, IL-10 and IL-6 in TPTL, reduce adverse pregnancy conditions, prolong gestational weeks, and has higher safety and better application value.