OBSTETRICS (MIDWIFERY). Obstetrics, together with Gynaecology (q.v.) and Paediatrics cover the greater part of the reproductive cycle (i.e., from the parents of one generation to those of the next), the portion falling strictly within the sphere of Obstetrics being from conception through pregnancy, labour and lying-in up to the time of the return of the mother to her ordinary duties. The start may be made even before conception for the obstetrician may be called on to advise as to the mar riageability of a woman, i.e., of her capacity to be a wife and mother, because of some disease or deformity of the genital organs or bony pelvis, or general disease, as of the heart, lungs or elsewhere, on which his experience of the effects in pregnancy and labour will be required. Midwifery is associated in the minds of the public with attendance at a confinement, and the woman who engages a doctor thinks of his duties as seeing her safely through the crisis of childbirth and relieving her, so far as the resources of medicine will allow, of the pains associated therewith.
comes on about 28o days after the first day of the last menstrual period and is divided into three stages. The first and longest is occupied by the opening up of the mouth of the womb; the second stage, lasting usually two hours or less, represents the time from full dilatation to the expulsion of the child; the third stage, half an hour or less, covers the period of the expulsion of the afterbirth. The motive power in all stages of labour is the contractions of the strong muscular wall of the womb, aided in the last two stages by the bearing down efforts of the abdominal muscles. The "pains of labour" are caused by the powerful colic-like contractions of the womb with, towards the end, the stretching of the passages as the child is being born.
The first stage may last even to days without harm to mother or child so long as the waters are unbroken, as the water-bag is an efficient protection to both, but danger to the child especially may result in those cases of premature breaking of the waters in which the presenting part does not come down and block the escape of all the water. The "dry" labour in which the water is lost is always a difficult one.
To be normal the head of the child, and the top of the head (vertex) should come first, that is, present, and does so in over 95 per cent. of cases and its position should be such that the hind
part of the head is born before the forehead. The labour is often longer and more difficult when the back of the child is backwards in the womb.
The chief difficulties arise from other presentations than those of the top of the head,—sometimes the face presents (once in 30o cases) and may cause a long and difficult labour, and more rarely the brow (1 in 1,200), a still more difficult presentation, as the passage of a full-time child is not possible until the presentation is altered to a face or a vertex. The most frequent abnormal presentation is a breech, when the buttocks come first and the head last, as it occurs about I in 4o cases. It, however, is not more serious to the mother than a vertex presentation, but the child is more likely to be still-born, being suffocated owing to the head coming last. Another, and happily rare, malpresentation is the cross-birth (I in 25o) in which the child lies across the passage, as if not changed, it completely obstructs the birth. Twins occur about once in 8o births, and add slightly to the risks, because the children are often small and the labour premature and slow with the first child. The second child is usually born easily because the passages are already dilated. A single unduly large child is much more likely to give rise to difficulty; it is always unfortunate if the child weighs over i olb.,—the more desirable weight is one of 6 to 71b.
the more serious complications are those giving rise to (I) haemorrhage during birth (commonly due to misplacement of the after-birth which is in front of the child and to early separation of the placenta), (2) convulsions (eclamp sia), occurring usually in women with kidney disease and (3) labour obstructed by deformity of the pelvic bones narrowing the bony canal through which the child must pass or by tumours blocking the canal. In the marked degrees of pelvic deformity the only chance of obtaining a living child is by Caesarean Section (q.v.). Delivery by the natural passages in such cases may be possible only by destroying the child and the risk of injury to, and death of, the mother in these destructive operations may be as great as the Caesarean operation.