The cervical are as important as the corporeal changes, though differ ent in their nature. Pajot states: " there are general, daily changes in the cervix during pregnancy; but there are many exceptions to this rule, and numerous degrees in the amount of change." These we will study. As in the body, the changes may be in consistency, extent, form, size of orifice and cavity, direction and position.
1st. Consistency.—The first change is softening; this is gradual, and does not occur equally in all parts of the cervix. It increases until the whole cervix is softened at full term. It begins in the mucosa of the os tincte, and the internal portion of the lips, then it occurs throughout the whole lip and the remainder of the cervix, the upper portion being softened last of all. Thus the process is from below up; and this, too, in primi parte as well as multiparw. But as the cervix of the latter is shorter, from previous pregnancies, the softening appears to be more rapid. In primiparm the softening is more marked, and in the third to fourth month the os tincte is softened to a depth of .11 to .19 of an inch; at the sixth month, it has extended half through the vaginal portion; at the eighth month, all the vaginal portion is soft; and during the ninth, the supra vaginal portion commences to soften.
The causes are (Lott), first, increase in size, and augmentation of number of the cervical elements; and, secondly, stasis from pressure of the festal head. The latter cause is potent chiefly towards the close of gestation.
2d. Size.—It is a mooted question whether the length, width and thickness of the cervix undergo change during pregnancy.
While many of the older authors (Rcederer, Stein, Baudelocque and later, Velpean) claimed that there was progressive shortening of the cervix during pregnancy, Stolz, Pajot, Depaul, Scanzoni and Cazeaux denied that any change in length occurred, and that the shortening was simulated by the approach of the internal and external orifices, and widening of the space between them. Mme. Boivin, Kilian, Hoist, M. Duncan, Tarnier and
Chantreuil claim that it is elongated rather than shortened, although they limit this increase to a few hundredths of an inch. Taylor, Spiegelberg, Muller, Schroeder and ourselves agree with Stolz, Pajot, Dubois and De paul. In 1877, Martin studied this subject, and, after many measure ments in multipane and primiparEe at different epochs of pregnancy, he drew the following conclusions: In the later months of pregnancy, the cervix increases in all directions in both primiparEe and multipane. It grows longer and wider. The en gaging of the head has no other influence than to hasten this change, and to cause its rapid and perfect completion. The differences in size in the cervix in the last months of pregnancy cannot be appreciated, either in primiparal or multiparEe, with exactitude, and hence cannot aid in differ ential diagnosis.
Martin admits that the cervix lengthens, and Tarnier and Chantreuil agree in this opinion. But this, for them, is only slight, while Martin's figures are a little larger. The precautions the latter took in measuring seem to prove a true lengthening, and one can no longer say, with Stolz, that the cervix lengthens only two weeks before delivery.
During these two weeks, Stolz, and Tarnier and Chantreuil, state that the cervix suffers another change, its obliteration. We have found this phenomenon occurring later on, often in the three or four days imme diately preceding delivery.
This obliteration is totally different from dilatation of the cervix. The latter is a physiological phenomenon of labor, while the former is a phe nomenon of pregnancy, which regularly occurs during the last days, I might say in the last hours of pregnancy, by an insensible labor, of which the woman is not aware. It precedes dilatation, and warns us of the on set of delivery. It is always understood that we speak of delivery as at full term.