ABSTRACT
It has been established that during pregnancy the body undergoes many physiologic adjustments. This would be foreseen even in the absence of investigative data. One of the apparently earliest studies of the blood picture of the rhesus monkey throughout its mean ~165-166-day-long gestation period was carried out by Allen and Siegfried (1966) (Table 1). Forty-two pregnant monkeys were monitored; one aborted on the 89th day of pregnancy and nine subjects failed to deliver naturally at term (of these, three viable and ve dead infants were obtained at cesarean section while the remaining monkey delivered a stillborn infant on the 189th day of gestation). Eleven scheduled femoral blood samplings, including an initial prepregnancy phlebotomy, were obtained from all subjects throughout the 179 days of monitoring. The most notable observation regarding the subjects’ erythrocytes, in the opinion of the investigators, was the marked elevation in the erythrocyte sedimentation rate (Esr) that increased from an initial mean 1.4 mm/hr (per Wintrobe tube) at around the 120th day of pregnancy to a maximum of 22 mm/hr by the time of delivery. The sedimentation rate declined soon after parturition and returned back to normal by 15-19 days postdelivery (Figure 35). The increased sedimentation rate was attributed to the increase in plasma brinogen and globulin. The Esr was used to estimate the stage of pregnancy, time of delivery, necessity for cesarean section, and to forecast possible abortion. It was noted that if there were a rapid increase in the sedimentation rate during early gestation, one would anticipate an abortion. As the monkey approached the time of delivery, little difculty would be encountered in the gestation as long as the sedimentation rate remained elevated. If a sharp reduction in Esr did present without delivery, the death of the infant in utero would occur within 48 hours unless the infant were surgically extracted. The investigators also noted that there was “an absence of any appreciable change in the hematocrit and hemoglobin level” during gestation (Table 1). The mean hematocrit and hemoglobin concentrations for the rst approximate 100 days following conception (including the pregravid value) were minimally higher than for the remainder of the pregnancy (Hct and Hb for the rst ~100 days versus the remaining ~65 days, respectively: Hct 40.6 and 39.5%; Hb 12.0 and 11.6 g/dL). The data were not statistically analyzed, and erythrocyte counts were not performed.
