Parturition In Women Research Articles

Endocrine Regulation of the Initiation and Maintenance of Parturition

This article examines the research being done and the hypotheses that have been formulated to understand further those processes that act to initiate parturition in women.

Blood progesterone levels in relation to parturition.

The hormonal mechanism that initiates parturition is still not clearly under¬ stood, although numerous theories have been put forward to explain it. The advocates of the oxytocin theory point out that it is possible to induce a seem¬ ingly normal labour in women and rabbits by oxytocin infusion (CaldeyroBarcia & Poseiro, 1959). On the other hand, total hypophysectomy apparently does not interfere with the normal course of parturition in women (Little, Smith, Jessiman, Selenkow, van't Hoff, Eglin & Moore, 1958), and in the rabbit oxytocin injections are only effective during the last few days of preg¬ nancy (Schofield, 1957). Ifoxytocin is the factor which precipitates parturition, it would be difficult to explain those cases of twin pregnancy in women with a double uterus, in which the birth of one twin may precede that of the other by several weeks (Csapo, 1959; Kennedy, 1959). Furthermore, in the pregnant mare it is common to observe a very pronounced milk ejection reflex

THE ONSET OF OVULATION DURING THE PUERPERIUM

50 unselected puerperal women aged 18 to 37 years most primiparae were followed by means of a daily rectal basal body temperature from the time they left the hospital until approximately 6 months postpartum. Endometrial biopsies were taken in selected cases to correlate elevated basal temperatures with possible functional corpus luteum. 24 of the patients lactated for 1 week or less 17 for 1 month and 9 for 1-3 months. In the nonlactating patients average onset of the catamenia was 7.7 weeks; for those lactating a month 7.9 weeks; and for those lactating 1-3 months 11 weeks. The initial ovulation following parturition in women who did not lactate occurred at an average of 10.2 weeks; it increased slightly to 10.6 weeks when lactation continued for 4 weeks and appeared at an average of 17.0 weeks after 3 months lactation. Endometrial biopsy specimens showed stromal growth with striking large spindle-like cells abundant loose reticulum and notable hypovascularity. Many apparently resting endometria actually had distended uterine glands which appear to be stimulated mildly often growing closely together. The progestational effects seemed incomplete and slight compared to the usual postovulatory phase. During the puerperium there seems to be a gradual preparation of the uterus for subsequent pregnancy. These conditions occur somewhat more rapidly in nonlactating women but even here there is considerable delay during which the endometrial elements proliferate but slightly. Patients with low metabolism tended to ovulate later and also had more difficulty in c ontinuing lactation. Menstruation tended to occur in the presence of lactation after the 3rd month postpartum; conversely before the 3rd month lactation almost always ended before menstruation occurred. Those who menstruate during lactation frequently also ovulate but nonmenstruating lactating women rarely ovualte. Women not lactating tended to have 1st ovulating about 10 weeks postpartum while nursing women tended to have it within 1 month of cessation of lactation. The effect of pregnancy seems to be as important as lactation in inhibition of ovulation during the early weeks postpartum.

Calculations Respecting the Period of Parturition in Women

Calculations Respecting the Period of Parturition in Women

Calculations Respecting the Period of Parturition in Women

Calculations Respecting the Period of Parturition in Women