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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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Journal ArticleDOI
TL;DR: This new sex-specific, population-based reference should improve clinical assessment of growth in individual newborns, population -based surveillance of geographic and temporal trends in birth weight for gestational age, and evaluation of clinical or public health interventions to enhance fetal growth.
Abstract: Background. Existing fetal growth references all suffer from 1 or more major methodologic problems, including errors in reported gestational age, biologically implausible birth weight for gestational age, insufficient sample sizes at low gestational age, single-hospital or other non-population–based samples, and inadequate statistical modeling techniques. Methods. We used the newly developed Canadian national linked file of singleton births and infant deaths for births between 1994 and 1996, for which gestational age is largely based on early ultrasound estimates. Assuming a normal distribution for birth weight at each gestational age, we used the expectation-maximization algorithm to exclude infants with gestational ages that were more consistent with 40-week births than with the observed gestational age. Distributions of birth weight at the corrected gestational ages were then statistically smoothed. Results. The resulting male and female curves provide smooth and biologically plausible means, standard deviations, and percentile cutoffs for defining small- and large-for-gestational-age births. Large-for-gestational age cutoffs (90th percentile) at low gestational ages are considerably lower than those of existing references, whereas small-for-gestational-age cutoffs (10th percentile) postterm are higher. For example, compared with the current World Health Organization reference from California (Williams et al, 1982) and a recently proposed US national reference (Alexander et al, 1996), the 90th percentiles for singleton males at 30 weeks are 1837 versus 2159 and 2710 g. The corresponding 10th percentiles at 42 weeks are 3233 versus 3086 and 2998 g. Conclusions. This new sex-specific, population-based reference should improve clinical assessment of growth in individual newborns, population-based surveillance of geographic and temporal trends in birth weight for gestational age, and evaluation of clinical or public health interventions to enhance fetal growth. fetal growth, birth weight, gestational age, preterm birth, postterm birth.

1,439 citations

Journal ArticleDOI
24 Jun 2000-BMJ
TL;DR: Fetal loss is high in women in their late 30s or older, irrespective of reproductive history, and should be taken into consideration in pregnancy planning and counselling.
Abstract: Objective: To estimate the association between maternal age and fetal death (spontaneous abortion, ectopic pregnancy, stillbirth), taking into account a woman9s reproductive history. Design: Prospective register linkage study. Subjects: All women with a reproductive outcome (live birth, stillbirth, spontaneous abortion leading to admission to hospital, induced abortion, ectopic pregnancy, or hydatidiform mole) in Denmark from 1978 to 1992; a total of 634 272 women and 1 221 546 pregnancy outcomes. Main outcome measures: Age related risk of fetal loss, ectopic pregnancy, and stillbirth, and age related risk of spontaneous abortion stratified according to parity and previous spontaneous abortions. Results: Overall, 13.5% of the pregnancies intended to be carried to term ended with fetal loss. At age 42 years, more than half of such pregnancies resulted in fetal loss. The risk of a spontaneous abortion was 8.9% in women aged 20–24 years and 74.7% in those aged 45 years or more. High maternal age was a significant risk factor for spontaneous abortion irrespective of the number of previous miscarriages, parity, or calendar period. The risk of an ectopic pregnancy and stillbirth also increased with increasing maternal age. Conclusions: Fetal loss is high in women in their late 30s or older, irrespective of reproductive history. This should be taken into consideration in pregnancy planning and counselling.

1,433 citations

Journal ArticleDOI
TL;DR: More research is needed into the etiologic roles of menstrual cycle characteristics, especially research examining the probability of prolonged exposure to both estrogens and progesterone concurrently.
Abstract: PIP: Early age at menarche, late age at menopause, and late age at first full-term pregnancy are linked to a modest increase in the risk of developing breast cancer. Some evidence suggests that the earlier the full-term pregnancy, the earlier the period of decreased susceptibility of breast tissue changes begins. Nulliparity is related to an increased risk for breast cancer diagnosed after 40 years old. Multiple full-term pregnancies decrease the risk of breast cancers diagnosed after 40 years regardless of the age at first birth. On the other hand, they may increase the risk for breast cancers diagnosed before 40 years old. Surgical removal of the ovaries protects against breast cancer. Breast feeding apparently protects against breast cancer in China, but a protective effect has not been established in the US. Other than shorter intervals between menstrual periods, which tend to increase the risk, research has not yet made clear the etiologic roles of menstrual cycle characteristics. Other unclear etiologic roles include increased intervals between births, spontaneous and induced abortion, infertility, multiple births at last pregnancy, and hypertension during pregnancy. Researchers tend to accept a mechanism to explain the epidemiologic characteristics of menstrual activity and the increased risk of breast cancer, but no mechanisms have emerged for the other likely risk factors. Greater exposure to estrogen and progesterone simultaneously are linked to early age at menarche, late age at menopause, and shorter menstrual cycle length. So far, data show that long-term combined estrogen/progestin hormone replacement therapy and long-term use of oral contraceptives increase the risk of breast cancer. Moderately increased risks linked to longterm estrogen replacement therapy and obesity in postmenopausal women indicate that estrogen alone influences breast cancer risk. Since much of the research on breast cancer risk factors are inconclusive, more research is needed, especially research examining the probability of prolonged exposure to both estrogens and progesterone concurrently.

1,417 citations

Journal ArticleDOI
TL;DR: CMV is a common congenital infection worldwide that can lead to permanent disabilities and there is an urgent need for interventions that can reduce the substantial burden of this often overlooked disease.
Abstract: SUMMARY We reviewed studies that reported results of systematic cytomegalovirus (CMV) screening on fetuses and/or liveborn infants. The overall birth prevalence of congenital CMV infection was 0.64%, but varied considerably among different study populations. About 11% of live-born infants with congenital CMV infection were symptomatic, but the inter-study differences in definitions of symptomatic cases limit the interpretation of these data. Non-white race, low socioeconomic status (SES), premature birth, and neonatal intensive care unit admittance were risk factors for congenital CMV infection. Birth prevalence increased with maternal CMV seroprevalence. Maternal seroprevalence accounted for 29% of the variance in birth prevalence between study populations. Maternal seroprevalence and birth prevalence were both higher in study populations that were ascertained at birth rather than in the prenatal period. Thus, timing of ascertainment should be considered when interpreting birth prevalence estimates. Birth prevalence was inversely correlated with mean maternal age, but this relationship was not significant when controlling for maternal seroprevalence. The rate of transmission to infants born to mothers who had a primary infection or a recurrent infection during pregnancy was 32% and 1.4%, respectively. Possible maternal primary infections (i.e. seropositive mother with CMV IgM) resulted in congenital infections about 20% of the time, but are likely to represent a mixture of primary and recurrent infections. In summary, CMV is a common congenital infection worldwide that can lead to permanent disabilities. There is an urgent need for interventions that can reduce the substantial burden of this often overlooked disease. Copyright # 2007 John Wiley & Sons, Ltd.

1,411 citations

Journal ArticleDOI
TL;DR: The ability to transfer one high-scoring blastocyst should lead to pregnancy rates greater than 60%, without the complication of twins, according to a retrospective review of blastocysts transfer in an IVF clinic.

1,410 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20246
202312,193
202225,740
20218,002
20207,983
20196,948