Characterization of breeding success and litter characteristics in the New Mexico Alcohol Research Center moderate drinking paradigm.

Rodent models of prenatal alcohol exposure are a powerful tool for studying causal factors of prenatal exposure effects. Under the New Mexico Alcohol Research Center, we combined a voluntary drinking-in-the-dark (DID) paradigm with a Volumetric Drinking Monitor (VDM) system to quantify maternal ethanol (EtOH) intake, drinking duration, and drinking patterns throughout gestation and determined whether these variables altered breeding success or early offspring development. Female C57BL/6J mice received daily 2-h access to either 20% EtOH or water using the VDM system. Following a two-week acclimation period, breeding was initiated while daily drinking continued throughout gestation until parturition. Breeding success, litter characteristics, and early growth were evaluated from 176 dam-sire pairings across three breeding cohorts, yielding over 800 offspring for demographic analyses. Maternal EtOH exposure did not affect pregnancy success, litter loss, litter size, pup weight at postnatal day 10, offspring sex distribution, or weaning weight. Average daily gestational EtOH consumption and duration of preconception EtOH exposure did not predict offspring outcomes. Although EtOH-exposed dams consistently exhibited front-loading behavior, neither front-loading status nor front-loading intensity was associated with litter characteristics or early offspring growth. Moderate voluntary maternal EtOH consumption, duration of exposure, or drinking pattern did not drive litter characteristics that may affect the early-life environment (pup number and sex) or early growth markers (P10 and weaning weight). These data indicate that differences in the early postnatal environment are not likely to be responsible for long-term behavioral and neurobiological phenotypes reported in offspring produced using this paradigm.