A Six-hour Pregnancy Test

Abstract

A 6-hr. biological test for pregnancy is described. The test is based upon the observation that 6 hrs. after the inj. of chorionic gonadotrophin into immature rats the ovaries show macroscopic evidence of marked vascular congestion. Microscopic examination of these ovaries revealed perifollicular zones of vaso-dilatation and diffuse hyperemia of the parenchyma. The test was performed as follows: 2 cc of urine was injected subcut. into each of 3 immature rats (weight 35-45 gs.) and autopsied at the end of 6 hrs. In positive cases the ovaries were enlarged and bright red in appearance, in sharp contrast to the small white or faintly pink ovaries of the control animals. The accuracy of this test was investigated in 110 urine specimens comprising 78 from pregnant women (the length of pregnancy varying from approx. 18-280 days), one from a patient with chorio-epithelioma and 31 from non-pregnant sources (cyclical menstruation, primary and secondary amenorrhea, menopause, functional sterility with delayed menstrual periods, adrenal cortex carcinoma and normal males). With but one exception all of the tests performed on the pregnancy urines and upon the urine from the chorio-epithelioma case were read as positive. The one exception was a negative reading made on the urine of a patient 5 days after the date of her expected period. The test was repeated 1 wk. later and found strongly positive. The diagnosis of pregnancy was subsequently confirmed clinically. All of the 31 tests performed on the urine from non-pregnant sources were read as negative. Since the end-point of the test consists of a vascular reaction, it is imperative that the ovaries be examined immediately after death. A confirmatory 24-hr. test is also described which is based on the proliferation of the epithelial and muscular elements of the immature rat vagina, induced by the estrogens present in the pregnancy urine.