Tehran University Medical Journal

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Background: Ondansetron is a 5-hydroxytryptamine receptor antagonist which is a highly effective antiemetic for postoperative and chemotherapy induced nausea and vomiting. It is an off-label drug to treat nausea and vomiting of pregnancy but availa-ble data about its safety is limited. In this study our purpose was to evaluate neonatal outcomes in women who received this treatment. Methods: This study is a descriptive retrospective case series study, included 22 preg-nant women who treated with ondansetron due to repeated nausea and vomiting unre-sponsive to our center's protocol, at Mahdiyeh Hospital, Tehran, Iran from May 2006 to September 2014. We investigated neonatal factors including: gestational age at birth, stillbirth, neonatal birth weight, apgar score, need to NICU admission and major birth defects. Results: The outcomes of 22 pregnancies and 22 newborns are presented here. We had two twin pregnancies and two abortions. Ondansetron was initiated in 18 cases (72%) on average gestational age of 9 weeks, during organogenesis. In 8 cases (32%) on-dansetron continued till third trimester of pregnancy. In primary evaluation, all the pa-tients had ketonuria, 15 cases (60%) had hypokalmia (K< 3.5), 3 cases (12%) had ab-normal TSH that all of them were hyperthyroidism and 5 cases (20%) had abnormal liver function test (LFT) Three patients (12%) had positive urine culture, one patient had hypercalcemia and one patient who was known a case of hypocalcemia had low serum calcium. The mean time of admission due to hyperemesis gravidarum (HG) was 5 days (2-10 sd=1.92). In this study we had only one preterm birth and the mean neo-natal birth weight was 3110 gram, one newborn was low birth weight due to preterm birth. Finally none of newborns had low apgar score, no one needed to NICU admis-sion and no congenital anomaly was seen in neonates. Conclusion: Ondansetron taken during pregnancy was not associated with increased risk of adverse fetal outcomes.