Maternal obesity is associated with and causal to a myriad of adverse pregnancy and neonatal outcomes [1]. Studies have shown adverse pregnancy outcomes to be associated with excessive gestational weight gain (GWG) as well, including hypertensive disorders of pregnancy and preterm delivery, both indicated and spontaneous [1].1 Pregnant people with obesity have the highest prevalence of excessive GWG with rates exceeding 50 % [2].

Obesity is also associated with pre-pregnancy hypertension, or chronic hypertension, which often requires medical treatment [3,4]. The most used and recommended antihypertensive medication classes during pregnancy are beta-adrenergic blockers (BB) and calcium channel blockers (CCB), namely labetalol and nifedipine, respectively [3].

Pharmacological management of hypertension in the nonpregnant population can impact weight gain; treatment with BB can result in weight gain due to reductions in basal energy expenditure by as much as 9 %, inhibition of lipolysis resulting in reduced free fatty acid mobilization from adipose tissue, and reduced insulin sensitivity [[5], [6], [7]]. Contrarily, CCBs have been shown to be weight-neutral or promote weight loss and have no effect on serum lipoprotein metabolism [[7], [8], [9], [10], [11]]. Animal studies further suggest that CCBs, particularly nifedipine, decrease white adipose tissue, increase insulin sensitivity, and increase energy expenditure in skeletal muscle [[12], [13], [14]]. While nifedipine can cause peripheral edema in up to 25 % of users, the effect on weight appears to be less significant, with an average weight gain of 0.5 % of body weight – less than 1–2 pounds for most people, including those with obesity [[15], [16], [17]].

Despite widespread use, the effect of antihypertensive medications on gestational weight gain has not been established. This paper addresses this knowledge gap by performing a retrospective cohort study of participants in the PeriBank database who have chronic hypertension and were treated during pregnancy with BB compared to CCB, with the medications initiated either pre-pregnancy or in the first trimester of pregnancy.