Multifetal pregnancy reduction: a Belgian experience

Multifetal pregnancy reductions were performed during the first trimester of pregnancy in 26 patients. Transabdominal intrathoracic KC1 injections were performed in 23 cases, and transcervical aspirations in 3 cases. There were 4 miscarriages (15%) during the second trimester, 18 pregnancies ended in 33 births, 4 pregnancies are going on uneventfully and are beyond 32 weeks. There was no maternal morbidity related to the procedure; fetal morbidity has been mild.

The etiology of ectopic pregnancy

The cause of ectopic pregnancy is associated with two major categories: the integrity of the oviduct and the quality of the fertilized ovum. Several conditions that alter the tubal transport system include inflammatory insults, intrauterine devices, surgical manipulation, tubal ligations, salpingitis isthmica nodusa, DES exposure, and induced abortions. Risk factors that may theoretically alter ovum quality or the hormonal environment include ovulation induction, fertilization in vitro, delayed ovulation, and transperitoneal ovum migration. As we continue to investigate the fallopian tube and the fertilized ovum as unique entities, our knowledge will increase about the cause of ectopic gestations.

Spontaneous abortion incidence in the treatment of infertility

Analysis of published series indicates that, irrespective of the method of data collection, close agreement exists on empirically derived incidences of spontaneous abortion in North American populations, provided that age, previous abortion history, and gravidity are controlled. The normal incidence of clinically apparent abortion among first pregnancies in women under age 30 years is in the range 8.3% to 11.0%. A comprehensive analysis of published series on pregnancies after infertility treatment indicates that only three therapeutic methods are attended by an abortion incidence that approaches this asymptote: ovulation induction with bromocriptine in hyperprolactinemic anovulation (11.8%; n = 1,233 pregnancies); artificial insemination with donor semen for azoospermia (11.4%; n = 326 first pregnancies); and operation for endometriosis (9.3%; n = 768 pregnancies). Abortion incidences accompanying other modes of therapy are higher. Because increased abortion incidence is not generally recognized as a specific reproductive difficulty in infertile couples, as are the other two: i.e., refractory infertility despite technically adequate therapy and ectopic pregnancy, plausible physiologic mechanisms for abortions in specific categories of disease or treatment type are described and discussed in detail. Moreover, abortion incidence is proposed to be a sensitive and objective parameter with which to assess distortions in human reproductive physiology, especially when competing methods of infertility treatment have overall pregnancy outcomes that are thought to be similar.

Cyclic changes in the human fallopian tube isthmus and their functional importance

Morphologic studies in rabbits have indicated that a column of tenacious mucus occupies the isthmic lumen in estrus. This secretion disappears after ovulation, and cilia are prominent at the time of ovum transport through the isthmus. This study was designed to seek evidence of similar mucus in the human fallopian tube isthmus. Isthmic segments were taken from 18 normally ovulating women throughout the menstrual cycle. Specimens were also obtained from 10 other women further to elucidate endocrine dependence of observed morphologic variations. Appearances consistent with luminal isthmic mucus were obtained in two women in the late follicular phase and in one woman immediately after ovulation. Observable mucus was absent and cilia were prominent in women in the early follicular phase, in the luteal phase, postmenopausally, in late pregnancy, and in the puerperium. The results described are consistent with the hypothesis that differential sperm and ovum transport in the human fallopian tube isthmus is at least partially determined by the presence or absence of estrogen-dependent luminal mucus.

Studies on the duration of egg transport by the human oviduct. II. Ovum location at various intervals following luteinizing hormone peak

The location of ova in the genital tract between 24 and 144 hours following the LH peak was determined in 23 normal women. Nineteen eggs were found in the Fallopian tubes between 24 and 96 hours and five eggs were recovered from the endometrial cavity between 96 and 144 hours following the LH peak. According to the present data and considering that ovulation occurs in the human subject nearly 17 hours after the LH peak, it is concluded that the transport of unfertilized ova in women is characterized by a period of retention in the ampulla, which lasts approximately 72 hours, followed by rapid transit through the isthmus and appearance of the ovum in the endometrial cavity around 80 hours after ovulation.

Pharmacologic modification of the time course of ovum transport in guinea pigs

Various agents were examined for their effects on ovum transport in the guinea pig. Estrogen significantly accelerated ovum transport in this species. The experiments further demonstrated that estrogen did not act by inducing prostaglandin synthesis, nor by altering plasma progesterone levels. The estrogen-induced acceleration was significantly antagonized by tamoxifen, an antiestrogen that acts by interfering with estrogen receptor synthesis. Cycloheximide also antagonized the effects of estrogen on ovum transport. These data suggest that the modification of ovum transport by estrogen is due to the entrance of estrogen into the nuclei of target cells, and subsequent protein synthesis. Although we assume that this action occurs at the level of the oviduct, our experiments do not prove this assumption.

[Histochemical and histological investigations on the human fallopian tube under different hormonal influences. I. Demonstration of ATPase with special reference to reactive ciliated cells (author's transl)]

The localization of the Mg++-activated adenosine triphosphatase (ATPase) in the human Fallopian tube has been studied by means of histochemical methods. The samples were obtained from 18 women in the age from 23--62 years. Some of them were treated by various steroid hormones. Endosalpinx ciliary ATPase-activity represents dynein and is therefore an indicator of ciliary motility. Estrogens and gestagens have a different influence on the ATPase-activity. All cilia of one ciliated cell react in the same manner and may be regarded as a reaction unit. The relation of negative to positive ciliary borders differs characteristically in the tubal isthmus, ampulls and infundibulum and coincides with commonly known phenomena of egg transport through the oviduct. Postovulatory, reaction units increase in ampulla and infundibulum compared with the proliferative phase. The oviducts of postmenopausal women possess but a scanty outfit of reaction units. Short-time treatment with estrogen in the early secretory phase results in a great number of reaction units in all tubal segments; a similar treatment in the proliferative phase diminishes the reaction units in the ampulla. Midcycle progesterone treatment activates the ciliary ATPase in the isthmus. Low doses of lynestrenol (minipill) in the proliferative phase leads to a decrease of reaction units in all tubal segments; the pattern of ciliary reaction under low doses of lynestrenol at the time of ovulation coincides with that of the proliferative phase. Treatment with a contraceptive steroid (0,05 mg ethinylestradiol and 0,25 d-norgestrel) causes a considerable activation of the ciliary ATPase in all portions of the oviduct.

From ovulation to blastocyst attachment. A review of early embryonic life in the mouse

The development of the blastocyst from ovulation to implantation is discussed with particular reference to control mechanisms that enable the embryo to attach to the uterine wall, using the mouse as a laboratory model. The physical and chemical changes in the uterus and within the blastocyst are seen as essential steps towards implantation. Evidence that the oestrogen plays a fundamental part in the overall control of these changes is demonstrated. The interrelationship between the hormones of early pregnancy and the uterine production of histamine and cycle AMP is viewed in conjunction with the development of the blastocyst and the decidual changes that occur in the uterus which are essential for nidation.

Peripheral plasma progesterone during egg transport in the rabbit

Peripheral plasma progesterone concentrations were measured in New Zealand rabbits every 6 hr beginning 12 hr before and continuing until 96 hr after either natural mating, hCG injection, or saline injection. The number of ovulation points in naturally mated animals (9.3 +/- 0.6, mean +/- SE) was not significantly different from that in hCG-injected animals (8.6 +/- 1.5). There was a surge in progesterone secretion following both mating and hCG injection. Plasma progesterone concentrations reached a peak prior to ovulation and then fell to basal levels at the time of ovulation. Beginning at approximately 30 hr after the ovulation-inducing stimulus, there was a progressive, significant (P less than 0.001) increase in plasma progesterone concentration, which continued for the duration of the sampling period. The initiation of the postovulatory increase in progesterone secretion corresponds temporally with the movement of eggs from the ampullary-isthmic junction into the isthmus. The progressive increase in plasma progesterone between 30 and 72 hr after the induction of ovulation corresponds with the gradual movement of eggs through the isthmus into the uterus. The data suggest that movement of eggs through the oviductal isthmus is influenced by the postovulatory secretion of progesterone.

Changes in the sensitivity of adrenergic receptors in the oviduct during early gestation in the rabbit

There is evidence to indicate that the transport of an egg through the rabbit oviduct is controlled through an interaction of the sympathetic nervous system and ovarian hormones. The effect of norepinephrine (NE) on the contractility of the oviduct during the first 8 days of gestation was studied using the rabbit perfused oviduct. The sensitivity of the alpha-adrenergic receptors of the oviduct to NE decreased progressively during early gestation. This was reflected in a potency change and a decrease in the maximal response obtained. These data support the concept that an isthmic sphinctering effect mediated by the autonomic nervous system may play a role in the regulation of egg transport through the oviduct. Blood pressure responses to NE did not change during early pregnancy except that the responses to NE were significantly enhanced immediately after mating. This suggests that the sensitivity changes to autonomic agents during early gestation may be selective for reproductive tissues.

A biophysicist's view of ovum transport

Experimental evidence justifying the selection of primary variables in ovum isthmic transport is evaluated. Peristaltic pumping alone cannot account for the observed ovum motions, however, the theory of pressure forcing of pellets through narrow tubes when combined with the dynamic and motile properties of the mucosal and muscular layers of the isthmus, appears capable of modeling the physiological mechanism. In this model the hormonally dependent tubal compliance is a controlling element of transport rate. The contractile activity statistically distributed both spatially and temporally, provides a persistent though irregular directionality to the movement.

Effects of prostaglandins on oviductal motility and egg transport

The effects of prostaglandins (PGs) on muscular activity of the oviductal isthmus and on the rate of tubal egg transport are reviewed. In consideration of the available data a mechanism by which PGs contribute to the physiological control of egg transport is suggested. In vivo experiments have demonstrated that E-series PGs relax while F-series PGs stimulate muscular activity of the oviduct in humans, subhuman primates and rabbits. These effects are mutually antagonistic. The response of oviductal muscle to PGs appears to be affected by ovarian steroids; progesterone increases the response to PGE1 and decrease the response to PGF2alpha. Oviductal tissue concentrations of PGF increase in a distal to proximal sequence following ovulation-induction in the rabbit. Also, proximal isthmus binding of PGE1 t tended to be greater in 72-hour pregnant rabbits than in estrous rabbits, while binding of PGF2alpha was greater in estrous than in 72-hour pregnant animals. It is suggested that the preovulatory increase in ovarian estradiol secretion stimulates PGF synthesis in the oviductal tissue in a sequential fashion, the peak value occurring when the oviductal isthmus is most sensitive to stimulation by PGF2alpha. The changes in tissue concentration of PGF and in sensitivity to PGF2alpha could contribute to occlusion of the isthmus and prevent premature passage of eggs into the uterus. An increase in ovarian progesterone secretion after ovulation may decrease tissue PGF, decrease the response to PGF2alpha stimulation, and increase the response to PGF1. These changes may then allow a progressive movement of eggs through the isthmus into the uterus. Several questions regarding this proposed mechanism remain unanswered.