Clinical reproduction and fertility最新文献

This study was designed to evaluate the role of luteinizing hormone (LH) and prolactin (PRL) in regulating pulsatile progesterone secretion in the human. This was done first by correlating the frequency of progesterone, LH and PRL pulses during the mid-luteal phase of normal cycles. Second, by increasing the frequency of LH pulses with naloxone and GnRH injections and examining the impact on progesterone pulse frequency. Third, by abolishing PRL pulsatility with metoclopramide and looking at the effect on progesterone pulsatility. Nine normal subjects in the mid-luteal phase (4-10 days after the initial postovulatory rise in progesterone) were studied for 8 h with blood samples taken at 15 min intervals. Each sample was assayed for progesterone, LH and PRL and the pulse frequency (number of pulses in 8 h) determined for each hormone. The mean pulse frequencies were 2.3 (s.e.m. = 0.4) for progesterone, 1.3 (s.e.m. = 0.4) for LH, and 2.1 (s.e.m. = 0.3) for PRL. Cross-correlation analysis showed that there was no significant synchrony between pulses of progesterone and pulses of LH and PRL. When naloxone was given to six normal subjects in the mid-luteal phase, the mean LH pulse frequency (number of pulses in 6 h) was increased from 2.2 (s.e.m. = 0.3) during a saline infusion to 3.2 (s.e.m. = 0.5) during the naloxone infusion (P less than 0.05). However, the mean pulse frequency for progesterone remained unchanged during the saline and naloxone studies. There was no significant difference between the mean serum LH in the saline and naloxone groups, and the mean serum progesterone concentration was not significantly altered.(ABSTRACT TRUNCATED AT 250 WORDS)

Historically, immigration has played an important role in the demographic evolution of the modern Australian society. In order to measure the demographic impact of immigration, it is necessary to study the fertility behaviour of various immigrant groups in Australia. In this paper, ethnic differences in Australian fertility have been analysed, using country of birth as a surrogate variable for ethnicity. Main sources of data used are the population censuses and the birth registers. Most of the data presented refer to 1981, as analysis of data pertaining to 1971 and 1976 was reported in earlier papers. The study has shown that fertility of most of the European immigrants (except the Dutch and the Maltese), has been converging towards the Australian norm. The non-European immigrants have lower fertility, with the exception of the newly arrived refugee groups from Asia and the Middle East.

Although setting up a clinical trial to test the efficacy of a method of contraception may appear to be a simple exercise, in practice, unless the aim is well delineated, the trial carefully designed, and the staff participating in the trial carefully briefed, problems will arise which prevent a successful outcome. Possible areas of bias such as selection of participants and staff prejudices must be eliminated, otherwise the value of the results may be diminished. Ethical considerations must be addressed regarding voluntary participation, information for participants, delineation of risk to participants and informed consent.

Male infertility is a significant health problem for which few aetiological factors have been identified. The role of occupational exposure is largely unknown but certain substances such as 1,2-dibromo-3-chloropropane, oestrogen, heat, lead and microwaves have been reported to impair spermatogenesis in workers. Other agents which interfere with reproductive performance in experimental animals such as cadmium, manganese, organophosphates and some solvents have not been studied sufficiently for their occupational risks to be fully known. Some occupational exposures, extensively studied, appear to convey little or no risk to male fertility including radiological exposure, anaesthetic gases and Agent Orange. It is clear that the range of substances potentially hazardous to male reproduction is great but the number of agents for which the evidence is unequivocal is very small.

Once other causes of hyperprolactinaemia have been excluded it is reasonable to assume that the cause lies within the hypothalamus or the pituitary. The pituitary may be the site of lactotroph hypertrophy and hyperplasia, a micro-adenoma or a macro-adenoma. Sixty-nine pregnancies in 53 patients, who required treatment of hyperprolactinaemia prior to the onset of pregnancy, have been observed. It is the purpose of this review to describe these patients, discuss the effects of pregnancy upon any pituitary lesion, and to discuss the effects of hyperprolactinaemia or the treatment of hyperprolactinaemia upon pregnancy. Based upon experience and the discussion of these data, recommendations for treatment of the hyperprolactinaemic pregnant patient will be made.

The majority of men who present with infertility have oligospermia or asthenospermia which renders them subfertile; pregnancies occur at lower than normal rates. Currently available treatments for this group are of uncertain value. This paper outlines an approach to controlled trials to test old and new methods for their ability to improve semen quality and increase pregnancy rates. As well as careful design, the need for control groups and large numbers of subjects is emphasized. Control groups are necessary because pregnancies and apparent or real spontaneous improvements in semen test results occur without treatment. Trials to evaluate differences in pregnancy rates need to be large because pregnancy rates are low and the margin for improvement narrow. Most untreated infertile couples have average pregnancy rates of less than 5% per month, whereas pregnancy rates in the general community average 20% per month. Under these circumstances, small trials with less than 20 pregnancies are unhelpful as they are not sensitive enough to detect less than threefold differences in pregnancy rates between groups. The number of subjects required for a trial can be calculated or determined from tables or graphs. A 50% difference in pregnancy rates in two groups given alternative treatments only has a high chance of being statistically significant if there are hundreds of subjects achieving a total of approximately 200 pregnancies in the trial. Such large trials can only be performed by several centres collaborating.

Registers of reproductive outcomes can be used to obtain information about the incidence of health problems related to pregnancy and to study associated risk factors and underlying causes. In Australia, a national data system for congenital malformations, based on multiple sources of notifications, has provided data to determine the incidence of major malformations over a 3-year period (1981-1983) and to study regional variations in incidence possibly due to environmental or other teratogens. A national register of pregnancies resulting from in vitro fertilization (IVF) has been established by obtaining reports from IVF units for pregnancies completed by the end of 1983. This register, developed in collaboration with the Fertility Society of Australia, has been used to describe the characteristics of infertile couples and the management of IVF pregnancies and to determine the incidence of pregnancy losses and major congenital malformations. Confidentiality issues were important in setting up both data systems.

Throughout most of human history 'natural fertility' and life expectations of about 35 years kept population numbers reasonably balanced; but the achievement of life expectations of 75 or more years destroyed this 'natural' system. As longevity increased amongst Western peoples, explosive growth rates were only prevented by increasingly efficient checks on fertility. Today, these checks are so universal and so efficient in Australia and in many other Western countries that 'intrinsic' levels of fertility are below generation replacement level. Changes in fecundity were not a significant factor in this demographic revolution; at least 10-12% of couples remain without issue, but the prime cause of the change is the evolution of the two-child family, a process which now involves only about a sixth of a couple's fecund married life. For the rest of their years most couples are now voluntarily infertile. Correction of involuntary sterility is important to individual couples but has little significance in terms of generation replacement.

The detection of the spontaneous LH surge in 12 infertile women being monitored for transfer of frozen-thawed or donor embryos was studied using plasma radioimmunoassay (RIA), urinary RIA and a dip-stick enzyme immunoassay. Ten of the 12 women had plasma LH surges and in all but one woman the dip-stick assay detected the LH surge to within 12 h of the plasma RIA. The urinary RIA detected the LH surge in only six of the 10 women. In two of these cases the surge was detected 24 h and 36 h later than by plasma RIA. The dip-stick assay has many advantages and could be usefully integrated as a mode of monitoring ovulation in infertility therapy.