CORPUS LUTEUM OF PREGNANCY. 



719 



Fig. 239. 



CORPUS LUTEUM of 

 pregnancy, at term, from a 

 woman dead in delivery 

 from rupture of the uterus. 



more, becoming of a faint yellowish-white color, not unlike that pre- 

 sented at the end of the third week. Its texture is thick, soft, and 

 elastic, and it is strongly convoluted. An abundance of fine red vessels 

 can be seen penetrating from the exterior into 

 the interstices of its convolutions. The central 

 coagulum is reduced by this time to the condi- 

 tion of a whitish radiated cicatrix. 



Its atrophy continues during the ninth month. 

 At the termination of pregnancy, it is reduced in 

 size to 12 or 13 millimetres in length and less 

 than 10 millimetres in depth. (Fig. 239.) It is 

 then of a faint indefinite hue, but little contrasted 

 with the remaining tissues of the ovary. The 

 central cicatrix has become very small, and ap- 

 pears only as a thin whitish lamina, with radi- 

 ating processes which penetrate between the in- 

 terstices of the convolutions. The whole mass 

 is still quite firm to the touch, and is readily 

 distinguishable, both from its size -and texture, 

 as a prominent feature in the ovarian tissue, 

 and a reliable indication of pregnancy. The 

 convoluted structure of the external wall is very 

 perceptible, and the point of rupture, with its external peritoneal cicatrix, 

 still distinctly visible. 



After delivery, the corpus luteum retrogrades rapidly. At the end of 

 eight or nine weeks, it has become so much altered that its color is no 

 longer distinguishable, although indications of its convoluted structure 

 may still be discovered by close examination. These traces of its 

 existence remain for a long time afterward, more or less concealed in 

 the ovarian tissue. We have distinguished them, in one instance, so 

 late as nine and a half months after delivery. They finally disappear 

 entirely, together with the external cicatrix which previously marked 

 their situation. 



During the existence of gestation, the process of menstruation being 

 suspended, no new Graafian follicles are ruptured, and no new corpora 

 lutea are produced ; and as the old ones, formed before the period of 

 conception, fade and disappear, the corpus luteum which marks the 

 occurrence of pregnancy after a time exists alone in the ovary. In 

 twin pregnancies, we of course find two corpora lutea in the ovaries ; 

 but these are precisely similar to each other, and, being evidently of the 

 same date, need not give rise to any confusion. Where there is but a 

 single foetus in the uterus, and the ovaries contain two corpora lutea of 

 similar appearance, one of them belongs to an embryo which has been 

 blighted in the early part of pregnancy, and has failed of its develop- 

 ment. The remains of the blighted embryo may sometimes be dis- 

 covered, in such cases, in some part of the Fallopian tube, where it has 

 been arrested in its descent toward the uterus. 



