Progesterone: History,facts, and artifacts

Progesterone and its related molecules are a crucial tool in modern clinical practice, particularly in the fields of reproductive medicine. Its history is old, but still under development. Presently, the pharmacokinetic and pharmacodynamic profiles of progesterone is well-known and knowledge on natural progesterone (P4) and other molecules with progestational activity, namely progestogens or gestagens, are improved and their interest is still alive.Topics of great and current interest are progesterone and its role in assisted reproductive protocols, threatened and recurrent pregnancy loss, threatened preterm birth with favorable results on pregnancy, and perinatal outcomes. Moreover, progesterone provides several other positive effects on women's health.This paper describes the main chronological steps that characterized the history of progesterone, where scientific research and clinical practice are arrived and WHICH are the future perspectives on this hormone with a “never-ending history.”     

Sex ratio: a biological perspective of 'Sex and the City'

The primary sex ratio in humans differs remarkably from the theoretically expected equality of 1:1, and may be as high as 170 males to 100 females. A number of environmental, physiological and genetic factors have been observed to impact on the primary sex ratio: sexual behaviour, variation in hormonal concentrations, natural disasters, environmental pollutants and timing of conception. Nevertheless, no biological mechanism or interaction of factors has suitably explained this phenomenon, or that of the prenatal vulnerability of the male, the suspected higher sex ratio in spontaneous abortion and the male excesses in adult diseases related to the intrauterine environment. Knowledge of the environmental effects and causes of natural variation in the primary sex ratio will make possible its manipulation, which will have public health implications as well as cultural and social consequences.     

Sex ratio of live-born Hausa infants

Summary. With data from the birth registry of the Katsina Local Government Authority, the sex ratio was calculated for 1113313 Hausa children born alive between 1961 and 1980. The sex ratio was 1.07, which is significantly higher than the usually accepted value (<1.04) for populations of African origin. There was no seasonal variation or apparent relation to coital frequency or gonadotrophin levels. The sex ratio in another set of data comprising 5780 hospital births was 1.17 for normal and 1.31 for complicated deliveries. The sex ratio did not appear to be influenced by maternal age or parity. This set of data point to some selective bias in hospital statistics.     

Pregnancies complicated by retained placenta: Sex ratio and relation to pre-eclampsia

Pre-eclampsia and placenta accreta have opposite histological features of placentation. This study set out to test the hypotheses that the sex ratios in these two pregnancy complications are opposite and that these conditions are mutually exclusive. A population-based database covering all deliveries in South Australia between 1986 and 1995 and the hospital-based obstetric database of the Adelaide Women's and Children's Hospital, covering 8549 births between 1993 and 1995, were used to ascertain the sex ratios in singleton pregnancies and the sex ratios in those pregnancies in which there was retained placenta, hypertension in pregnancy, or pre-eclampsia. The likelihood of independence of occurrence or mutual exclusivity of retained placenta and hypertension in pregnancy or pre-eclampsia were also examined. The male:female sex ratio in the South Australian population was 1.077. In pregnancies with hypertension in pregnancy it was 1.165 (P<0.001) and in pregnancies with retained placenta it was 0.883 (P<0.0001). There was a trend to an increased sex ratio in pre-eclampsic pregnancy (1.248 in primigravid and 1.092 in multigravid women) but there was insufficient power to detect significance (P=0.207 and 0.470, respectively). Neither hypertension in pregnancy nor pre-eclampsia were mutually exclusive of placenta accreta: hypertensive disorders of pregnancy and placenta accreta occurred independently of each other. Our findings suggest that sex-linked antigens are unlikely to influence maternofetal interactions consistently to give rise to one but not the other pregnancy complication.     

Leptin in pregnancy: facts, questions and future

Leptin has been primarily considered as a protein secreted by the adipocyte and a regulator of satiety and energy homeostasis. A role for leptin in pregnancy was later suggested as circulating levels of leptin are high in the pregnant woman and leptin is synthetized within the placenta. Placental leptin production is increased in various obstetrical conditions associated with alterations of fetal growth (diabetes, preeclampsia). Furthermore, umbilical leptin can be viewed as a biomarker of fetal adiposity. Our aim is to review the putative roles of leptin in pregnancy.     

Sex ratio of births resulting from artificial insemination

Summary. A survey of available data has shown that the sex ratio of births is significantly affected both by the practice of artificial insemination (AI) and by the cryostorage of semen. Comparison of the sex ratio of all infants born in England, Scotland and Wales between 1969 and 1978 (51.5% males) with that of British births after AI showed that the prevalence rate of male births after AI with either fresh or cryostored semen was lower than that for the general population: fresh semen (47.8%); cryostored semen (42.9%). When data from European countries and the US were combined, AI with fresh semen significantly increased the prevalence rate of male infants to 57.7%, whereas AI with cryostored semen significantly decreased the rate to 49.7%. The mechanism/s whereby the cryostorage of spermatozoa affects the secondary sex ratio remains to be determined.     

Emergency contraception, myths and facts

Emergency contraception has the potential to reduce the United States unintended pregnancy rate by half. This article discusses the evidence on the safety and efficacy of emergency contraception, its side effects, as well as its mechanisms of action. Emergency contraception availability presents many opportunities for enhanced contraceptive care, beyond the obvious lapse in condom use, and evidence is lacking for contraindications to this expanded role. This article concludes that clinicians caring for women of reproductive age should recognize the importance of ready access to this medication to help prevent unintended pregnancies.     

Leucocytospermia, oxidative stress and male fertility: facts and hypotheses

Leukocytospermia is frequent and significantly increased (over 10(6)/ml) in 20% of male factor infertility. It induces the production of highly toxic reactive oxygen species (ROS) which impair genital track accessory glands and sperm cell functions. The seminal medium contains extremely potent antioxidative defenses which usually balance the oxidative stress. In vivo, these defenses can be overwhelmed when ROS production is extremely important and/or when it lasts for a very long period of time. Infertility can then appear. In vitro, ROS have been univoqually demonstrated for being highly toxic since spermatozoa are no longer protected. Sperm cell defects are : decrease of acrosome reaction and fusiogenic ability and increase of DNA fragmentations. In case of male factor infertility, a leukocytospermia represents an essential or an additional risk factor that should be treated, specially when in vitro therapy is to be scheduled, in order to improve gamete quality.