1. Pelvis at least 3.5 inches.—There is a difference according as we are dealing with a primipara or a multipara. In the latter everything de pends on how the previous labors have passed. If, at term, they have been simple, easy, and resulting in living infants, we need not induce labor, but can wait; if the forceps has been required, although easy and with living infants, we must be more reserved. We must never forget what we have already stated, that infants increase in size with the preg nancies, especially boys; and consequently in the fourth and fifth preg nancies we might meet with difficulties which did not exist in the others. We are, therefore, justified in inducing labor a little before term. With all the more reason, of course, if the woman is in the habit of bearing large children, if on palpation and on mensuration we suspect a large child, if the anterior labors have necessitated the forceps, resulting in dead children, or if the forceps has not sufficed, and the fcetus has had to be mutilated.
When the pelvis is at least 3.5 inches, after deduction, and the foetal head at term will be 3.7, reducible by .39 of an inch, labor should be in duced at eight months one week to eight and a half months, according to the obstacles met with in previous labors, and the supposed volume of the foetus.
If, on the other hand, we are dealing with a primipara, since infants are usually smaller, we may wait till term, or at least not induce labor till eight or ten days before term.
2. Pelvis of 3.31 this case, whether we are dealing with a primipara or a multipara, premature labor is indicated, and at eight months to eight and a half.
3. Pelvis of 3.12 labor is to be induced between eight and eight and a half months at the latest.
. 4. Pelvis of 2.9 inches.—Premature labor is to be induced between seven and a half and eight months.
5. Pelvis of 2.73 inches.—Premature labor is to be induced between seven months and seven months three weeks.
6. Pelvis of 2.53 to 2.34 inclies.—At seven to seven and a half months at the latest.
Below 2.34 inches, miscarriage should be induced; instances where in pelves of 2.14 inches living children have been obtained are very excep tional, and cephalotripsy and embryotomy are too dangerous for the mother.
Indeed, when we are going to induce premature labor, we must not consider this operation alone, for although in pelves of 3.5 to 3.12 inches we can usually extract living infants with the forceps, this is far from being the case where the contraction is less than 3.12 inches. Here we may be able to bring the flatus down to the pelvic floor, but no further, and be obliged to mutilate it. The greater the contraction of the pelvis, the greater the difficulty of mutilating operations, and hence the less the chances for the mother. It is of advantage to her, therefore, to substi tute miscarriage for premature labor.
We see, then, from the above figures, that it is in the most common degrees of deformity, 3.51, 3.31, 3.12, 2.73 inches, that it is, in general, of advantage to induce premature labor, and that the time of election corresponds to about these same figures, since the foetal head is reducible by .39 of an inch. These divisions, however, are not at all absolute, and the accoucheur must carefully study the obtainable data in each case be fore resorting to the operation. We must further remember that in rick ets both the fictus and the uterus develop above the brim, since the head cannot engage; and that, consequently, the size of the abdomen will always indicate a more advanced pregnancy than in reality exists. We must always take into account this exaggerated elevation of the fundus, particularly in case of contraction between 2.34 and 2.73 inches. Here premature labor should be induced between seven and seven and a half months at the latest, and since an error of 15 days is possible in our esti mation, we will often induce miscarriage, that is to say, not obtain a via ble child.
Once having determined on the induction of premature labor, another question presents itself—What is the presentation of the fcetus? Although, prior to the last few years, cephalic presentations were con sidered most favorable in contracted pelves, latterly, the experiments of Bud in, Champetier, Milne and Goodell, tend to show that the balance is in favor of pelvic presentations, certainly before term. We may well ask, therefore, if it would not be advantageous to convert head into breech by external manipulation? . We cannot answer this question at present. Facts are not numerous enough, and the future must decide. The good results from the forceps lessen as the degree of contraction increases; cephalotripsy and embryotomy always sacrifice the fcetus, and become the more dangerous for the mother with increase in degree of contraction. We are, therefore, justified in trying the method of Milne and Goodell, which has yielded them such brilliant results. (See subject of Contracted Pelves, Ibreeps and Version.) We give below the results of. Winckel at the Dresden Maternity, in cases of contracted pelvis.
Of 10,679 labors, from October, 1872, to the end of March, 1882, Winck el noted 300 cases of contracted pelvis with 356 labors; 129 of these women had rickets.
Weidling (Halle) divides his cases according to the number of labors thus: Ordinarily the general percentage is 25 per cent., or taken singly: sim ple twists 70.4 per cent.; double 10 per cent.; triple 1.6 per cent.
Prolapse of the cord was th3 cause of death in 33 per cent. of infants, that is, 1.8 per cent. more than in the other cases.