Atenolol and fetal growth in pregnancies complicated by hypertension

Atenolol use may be associated with growth retardation when given in pregnancy, although the relationship to trimester of initiation, duration of treatment, and its use as monotherapy is still uncertain. To compare the obstetric and fetal outcome between women receiving atenolol (as monotherapy) and other antihypertensive drug monotherapies, and also to investigate the effect of duration of treatment on fetal growth, we performed a retrospective cohort study of 312 pregnancies in 223 women attending an Antenatal Hypertension Clinic. Atenolol (as monotherapy) was given in 78 pregnancies (25.0%), other types of antihypertensive drugs as monotherapy were given in 53 pregnancies (17.0%), and multiple drug combinations were given in 90 pregnancies (28.8%). In 91 pregnancies (29.2%) no antihypertensive drugs were given. Atenolol was found to be associated with lower birth weight and ponderal index values, with a trend toward a higher prevalence of preterm (<37 weeks) delivery and small-for-gestational-age babies when compared to other antihypertensive drugs as monotherapy, or to no treatment. The adverse effect of atenolol was more pronounced in women receiving the drug earlier in their pregnancy, and continuing the drug for a longer duration. In conclusion, atenolol should be avoided in the early stages of pregnancy and given with caution at the later stages, as it is associated with fetal growth retardation, which is related to duration of treatment.