Topic
Pregnancy
About: Pregnancy is a research topic. Over the lifetime, 163969 publications have been published within this topic receiving 4013502 citations. The topic is also known as: pregnancy & gestation.
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TL;DR: In a study of mothers 13 to 24 years old who had the characteristics of most white, middle-class Americans, a younger age conferred an increased risk of adverse pregnancy outcomes that was independent of important confounding sociodemographic factors.
Abstract: Background Pregnancy in adolescence is associated with an excess risk of poor outcomes, including low birth weight and prematurity. Whether this association simply reflects the deleterious sociodemographic environment of most pregnant teenagers or whether biologic immaturity is also causally implicated is not known. Methods To determine whether a young age confers an intrinsic risk of adverse outcomes of pregnancy, we performed stratified analyses of 134,088 white girls and women, 13 to 24 years old, in Utah who delivered singleton, first-born children between 1970 and 1990. Relative risk for subgroups of this study population was examined to eliminate the confounding influence of marital status, educational level, and the adequacy of prenatal care. The adjusted relative risk for the entire study group was calculated as the weighted average of the stratum-specific risks. Results Among white married mothers with educational levels appropriate for their ages who received adequate prenatal care, younger teen...
977 citations
TL;DR: In this article, the authors evaluated the relation of invasive epithelial ovarian cancer to reproductive and menstrual characteristics, exogenous estrogen use, and prior pelvic surgeries, and found that women who had used fertility drugs and had long total duration of premenopausal sexual activity without birth control had increased risk of ovarian cancer.
Abstract: Data collected from 2,197 white ovarian cancer patients and 8,893 white controls in 12 US case-control studies conducted in the period 1956-1986 were used to evaluate the relation of invasive epithelial ovarian cancer to reproductive and menstrual characteristics, exogenous estrogen use, and prior pelvic surgeries. Clear trends of decreasing risk were evident with increasing number of pregnancies (regardless of outcome) and increasing duration of breast feeding and oral contraceptive use. Ovarian dysfunction leading to both infertility and malignancy is an unlikely explanation for these trends for several reasons: 1) The trends were evident even among the highly parous; 2) risk among nulliparous women did not vary by marital status or gravidity; and 3) risk among ever-married women showed little relation to length of longest pregnancy attempt or history of clinically diagnosed infertility. Risk was increased among women who had used fertility drugs and among women with long total duration of premenopausal sexual activity without birth control; these associations were particularly strong among the nulligravid. No consistent trends in risk were seen with age at menarche, age at menopause, or duration of estrogen replacement therapy. A history of tubal ligation or of hysterectomy with ovarian conservation was associated with reduced ovarian cancer risk. These observations suggest that pregnancy, breast feeding, and oral contraceptive use induce biological changes that protect against ovarian malignancy, that, at most, a small fraction of the excess ovarian cancer risk among nulliparous women is due to infertility, and that any increased risk associated with infertility may be due to the use of fertility drugs.
965 citations
TL;DR: It is suggested that concepts of teratogensis should be expanded to include alterations occurring subsequent to organogenesis during the differentiation and proliferation of fetal cells that could cause long-range effects upon behavioral, anthropometric, and metabolic functions.
Abstract: A profile characteristic of fuel economy in the mother during normal pregnancy has been delineated. The evidence indicates that pregnancy changes the metabolism of every class of foodstuff. The mechanisms by which the conceptus may be implicated are reviewed. The gestational interactions create a pattern of “accelerated starvation” whenever food is withheld, especially in late pregnancy, and they tend to “facilitate anabolism” when food is ingested. The consequent heightened metabolic oscillations during the shuttlings from fed to fasted state provide a basis for more aggressive therapy with exogenous insulin when endogenous insulin is lacking in pregnancy. It is emphasized that developing fetal structures may be exquisitely attuned to fine alterations in maternal fuel economy and that pregnancy complicated by diabetes may merely exaggerate these normal dependencies since maternal insulin affects all maternal fuels. The manifest changes in the offspring of mothers with. even the mildest limitations in insulin reserve, i.e., gestational diabetes, attest to the sensitivity of the relationships. It is suggested that concepts of teratogensis should be expanded to include alterations occurring subsequent to organogenesis during the differentiation and proliferation of fetal cells. Such changes could cause long-range effects upon behavioral, anthropometric, and metabolic functions. It is hypothesized that all of these could constitute expressions of fuel-mediated teratogenesis and that the potentialities should be incorporated into any evaluation of the outcome of pregnancy in gestations attended by disturbances in maternal fuel metabolism.
958 citations
TL;DR: Understanding molecular signaling networks that coordinate strategies for successful implantation and decidualization may lead to approaches to improve the outcome of natural pregnancy and pregnancy conceived from in vitro fertilization.
Abstract: Physiological and molecular processes initiated during implantation for pregnancy success are complex but highly organized. This review primarily highlights adverse ripple effects arising from defects during the peri-implantation period that perpetuate throughout pregnancy. These defects are reflected in aberrations in embryo spacing, decidualization, placentation and intrauterine embryonic growth, manifesting in preeclampsia, miscarriages and/or preterm birth. Understanding molecular signaling networks that coordinate strategies for successful implantation and decidualization may lead to approaches to improve the outcome of natural pregnancy and pregnancy conceived from in vitro fertilization.
949 citations
TL;DR: In this article, the authors measured changes in the oxygen tension within the human placenta associated with onset of the maternal arterial circulation at the end of the first trimester of pregnancy, and the impact on placental tissues.
Abstract: The aim was to measure changes in the oxygen tension within the human placenta associated with onset of the maternal arterial circulation at the end of the first trimester of pregnancy, and the impact on placental tissues. Using a multiparameter probe we established that the oxygen tension rises steeply from 50 mmHg at 12 weeks. This rise coincides with morphological changes in the uterine arteries that allow free flow of maternal blood into the placenta, and is associated with increases in the mRNA concentrations and activities of the antioxidant enzymes catalase, glutathione peroxidase, and manganese and copper/zinc superoxide dismutase within placental tissues. Between 8 to 9 weeks there is a sharp peak of expression of the inducible form of heat shock protein 70, formation of nitrotyrosine residues, and derangement of the mitochondrial cristae within the syncytiotrophoblast. We conclude that a burst of oxidative stress occurs in the normal placenta as the maternal circulation is established. We speculate that this may serve a physiological role in stimulating normal placental differentiation, but may also be a factor in the pathogenesis of pre-eclampsia and early pregnancy failure if antioxidant defenses are depleted.
947 citations