CHOLINESTERASE ACTIVITY IN PREGNANT-WOMEN AND NEWBORNS

Plasma and red blood cell cholinesterase activity in blood samples fro m 259 pregnant women and cord blood from some of their newborn were co mpared with samples from 25 nonpregnant female volunteers and with lab oratory norms (Ellman method). Plasma cholinesterase was significantly lower (p < 0.05) and red blood cell cholinesterase higher (p < 0.05) in pregnant women than in nonpregnant controls in a repeated measures analysis. By the sixth post-partum week, both plasma and red blood cel l cholinesterase were similar to nonpregnant control activity. Fetal c ord red blood cell cholinesterase activity was also lower than in nonp regnant women, but plasma levels were not significantly different. Whe n compared with standard laboratory normal ranges, most (98-100%) plas ma cholinesterase values in pregnant women and newborn were within ran ge, whereas the majority (59-87%, depending on trimester) of red blood cell levels were above range in pregnancy and below range in 53% of n ewborns. A low red blood cell cholinesterase in pregnant women is more consistent with a possible overexposure to anticholinesterases than a low plasma cholinesterase. Periods of altered sensitivity to specific cholinesterase inhibiting drugs and environmental agents are suggeste d by these findings.