title: Late Pregnancy β Blocker Exposure and Risks of Neonatal Hypoglycemia and Bradycardia.
abstract: β blockers are widely used in the treatment of hypertensive disorders during pregnancy. These medications cross the placenta and may cause physiologic changes in neonates exposed in utero. We sought to define the risks of neonatal hypoglycemia and bradycardia associated with maternal exposure to β blockers at the time of delivery in a large, nationwide cohort of Medicaid beneficiaries.
  
  
  
  We used a cohort of 2 292 116 completed pregnancies linked to liveborn infants of Medicaid-enrolled women from 2003 to 2007. We examined the risks of neonatal hypoglycemia and neonatal bradycardia associated with maternal exposure to β blockers at the time of delivery. Propensity score matching was used to control for potential confounders including maternal demographics, obstetric and medical conditions, and exposure to other medications.
  
  
  
  There were 10 585 (0.5%) pregnancies exposed to β blockers at the time of delivery. The risk of neonatal hypoglycemia was 4.3% in the β blocker-exposed neonates versus 1.2% in the unexposed; the risk of neonatal bradycardia was 1.6% in the exposed versus 0.5% in the unexposed. After controlling for confounders, risk remained elevated for both neonatal hypoglycemia and bradycardia among exposed pregnancies versus unexposed (adjusted odds ratio, 1.68, 95% confidence interval, 1.50-1.89 and adjusted odds ratio, 1.29, 95% confidence interval, 1.07-1.55, respectively).
  
  
  
  Our findings suggest that neonates born to mothers exposed to β blockers in late pregnancy, including labetalol, are at elevated risk for neonatal hypoglycemia and bradycardia.
authors: Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, and Department of Anesthesiology, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; and bbateman@partners.org.
authors: Brian T
authors: BT
authors: Bateman
authors: Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, and.
authors: Elisabetta
authors: E
authors: Patorno
authors: Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, and.
authors: Rishi J
authors: RJ
authors: Desai
authors: Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts;
authors: Ellen W
authors: EW
authors: Seely
authors: Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, and.
authors: Helen
authors: H
authors: Mogun
authors: Department of Anesthesiology, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; and.
authors: Ayumi
authors: A
authors: Maeda
authors: Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, and.
authors: Michael A
authors: MA
authors: Fischer
authors: Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.
authors: Sonia
authors: S
authors: Hernandez-Diaz
authors: Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, and.
authors: Krista F
authors: KF
authors: Huybrechts
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000009:adverse effects*; D001262:Atenolol / Q000008:administration & dosage / Q000009:adverse effects; D001919:Bradycardia / Q000139:chemically induced*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D046110:Hypertension, Pregnancy-Induced / Q000188:drug therapy; D007003:Hypoglycemia / Q000139:chemically induced*; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000139:chemically induced*; D007741:Labetalol / Q000008:administration & dosage / Q000009:adverse effects; D008297:Male; D018811:Maternal Exposure; D008790:Metoprolol / Q000008:administration & dosage / Q000009:adverse effects; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000188:drug therapy; D057216:Propensity Score
chemical_list: D000319:Adrenergic beta-Antagonists; D001262:Atenolol; D008790:Metoprolol; D007741:Labetalol