Life-history theory predicts a tradeoff between reproductive effort and lifespan. It has been suggested that this tradeoff is a result of reproductive costs accelerating senescence of the immune system, leading to earlier death. Longevity costs of reproduction are suggested for some human populations, but whether high reproductive effort leads to impaired immune function is unknown. We examined how reproductive effort affected postreproductive survival and the probability of dying of an infectious disease in women born in preindustrial Finland between 1702 and 1859. We found that mothers delivering twins had reduced postreproductive survival after age 65. This effect arose because mothers of twins had a higher probability of succumbing to an infectious disease (mainly tuberculosis) than mothers delivering singletons. The risk among mothers of twins of dying of an infectious disease was further elevated if mothers had started reproducing early. In contrast, neither female postreproductive survival nor the risk of succumbing to an infectious disease was influenced by the total number of offspring produced. Our results provide evidence of a long-term survival cost of twinning in humans and indicate that the mechanism mediating this cost might have been accelerated immunosenescence.
Cites: Proc Biol Sci. 2000 Jan 22;267(1439):171-610687823
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Cites: Proc Natl Acad Sci U S A. 2001 Feb 13;98(4):2071-611172077
Acute polyhydramnios in monozygotic twin pregnancy causes severe maternal discomfort and carries a high risk of premature labor. During the years 1980 to 1987, 36 patients with this complication were delivered in Sweden, giving an incidence of 1/20,000 births, or 1/200 twin births. In 18 patients (group A) who were treated with one or more amniotic taps, the delivery was postponed by 2 weeks, as compared with one week in 18 conservatively treated patients (group B). The peri- and neonatal death rate was 47% in group A and 58% in group B. Our own experience is that amniotic taps are safe if the amniotic fluid is removed slowly under prophylactic tocolysis. It gives symptomatic relief to the mother and may postpone labor until the gestational age of the twins is more compatible with survival.
The object of this investigation were the causes of the decrease of the frequency of twin births during the last two decades. In Moscow this frequency decreased from 1,19% in 1956 to 0,7% in 1973. Among the births the proportion of first births was observed to increase, as well as the proportion of very young mothers. The effect of this process on the women characterized by a tendency to polyembryony was more conspicuous, than in the average on the population as a whole. During the last decades the process of acceleration of puberty was observed both in the mothers of twins and in all the women in general. However a somewhat later onset of first menstruations is characteristic of the women having a tendency to polyembryony-Hormonal changes taking place in the course of acceleration are apparently one of the causes of the decrease of the twin births frequency.
In this retrospective cohort of 165,188 singleton pregnancies and 44,674 multiple-fetal pregnancies in Canada from 1984 to 2000, we compared the incidence of maternal complications. Multiple gestation pregnancies were associated with significant increases in cardiac morbidity, haematologic morbidity, amniotic fluid embolus, pre-eclampsia, gestational diabetes, postpartum haemorrhage, prolonged hospital stay, the need for obstetric intervention, hysterectomy and blood transfusion. Multiple gestation pregnancies are associated with an increased risk of morbidity for the mother. This should be taken into consideration in antenatal care of these women.
Amniocentesis is a relatively safe and reliable procedure. However, there probably is a slightly increased risk of fetal loss following amniocentesis (approximately 0.5%). Other risks are minimal. Amniocentesis should be performed by obstetrician-gynecologists familiar with both the indications for the technique of second-trimester genetic amniocentesis. Recent social trends, including the increased availability of medical information to the lay public and the interest of many women in delaying childbearing, will increase public demand for antenatal diagnosis. It is important that obstetrician-gynecologists prepare to meet these demands.
To assess the risk factors for preterm birth in twin pregnancies, particularly monochorionicity.
A cohort study of 767 sets of twins, each twin weighing more than 500 g, born between January 1, 1992, and December 31, 2001, at St. Joseph's Health Care in London, Ontario. Statistical analysis was performed using forward stepwise logistic regression models, with gestational age at birth less than 28 or 32 weeks as the outcome.
Polyhydramnios and chorioamnionitis were significant risk factors for preterm birth prior to 28 or 32 weeks' gestation. Monochorionicity was a risk factor for preterm birth prior to 32 weeks' gestation. Past term birth and maternal age over 30 years were associated with reduced risk for preterm birth.
Monochorionic placentation is a significant risk factor for preterm twin birth.
Epidemiologic data were analyzed for a total of 2,693 infants with esophageal atresia registered in nine congenital malformation registries around the world. The average recorded prevalence at birth was 2.6 per 10,000 births, with a significant variability among programs--and sometimes within a program--and a maximum prevalence of above 3 per 10,000 births. Clusters of infants with esophageal atresia were observed but may be random. An increasing rate was seen during the period 1965 to 1975 (Norway, South America, Sweden). The type of esophageal atresia was specified in only 439 cases, but no major differences were seen in the epidemiologic characteristics of infants with the most common type (distal fistula) and infants with other types. There was an excess of low birth weight and preterm birth, and infants with esophageal atresia had a birth weight 500 to 1,000 g less than normal infants in each gestational week. There was an excess of twins, apparently mainly or exclusively due to monozygotic twinning, but in only two pairs did both twins have esophageal atresia. There was no effect seen of maternal age, but low parity, irrespective of maternal age, was associated with an increased risk for esophageal atresia. Infant survival varied among programs and depended heavily on associated malformations. Among 1,107 sibs born before the proband and 385 born after the proband, only 25 (1.7%) had a serious malformation; three had esophageal atresia. In 57.3% of the infants with esophageal atresia, no other malformations were present, in 36.4% other major malformations were recorded, and in 6.3% there were chromosomal anomalies. The malformations present associated with esophageal atresia were analyzed: a large proportion entered the constellation sometimes called "caudal mesoderm spectrum of malformations": VATER, Potter, and caudal regression sequences.
Multiple pregnancy is one of the most important and preventable complications of in vitro fertilization (IVF) and embryo transfer. The general clinical practice in many IVF clinics is to transfer four or five embryos to older women if available, since pregnancy rates are lower in women older than 35 years of age. However, it is not clear whether the risk for multiple pregnancy is also lower.
Our objective was to investigate whether transferring a higher number of embryos actually improves pregnancy outcome in older women, without increasing the risk for multiple pregnancy and to investigate other factors that may affect the occurrence of multiple pregnancy.
The setting was university-based IVF program at The Toronto Hospital.
The design was a retrospective case series.
The outcome of 1116 IVF cycles between January 1992 and December 1993 was investigated according to different age groups.
The main outcome measure was multiple pregnancies.
Seventy multiple pregnancies resulted from a total of 242 pregnancies. Overall pregnancy and multiple pregnancy rates were inversely correlated with age. However, when the data were adjusted for the number of embryos transferred, this trend disappeared. The result of multiple regression analysis showed that the multiple pregnancy rate was higher without improving the pregnancy rate when the number of embryos transferred exceeded three, regardless of the age of the patients, especially when more embryos were available than the number of transferred ones.
The number of embryos transferred should be limited to a maximum of three regardless of the age of patients, to reduce the high frequency of multiple gestations in an IVF program.
Cites: Am J Obstet Gynecol. 1966 Feb 15;94(4):490-65903669