Abstract：
OBJECTIVE:To estimate why the live birth rate per implanted embryo is higher in twin than in singleton pregnancies. METHODS:Data from 1,159 singleton and 523 dichorionic twin pregnancies, obtained after assisted conception, were included. To account for the higher live birth rate observed in twin pregnancies, two possibilities were considered: embryo collaboration and assistance. To test these hypotheses, we compared the observed values for each possible outcome in twin pregnancies (double birth, single birth, double loss) with the expected values regarding as the null hypothesis that the survival of either embryo is independent from the presence of the other. The effect of maternal age was also examined. RESULTS:Live birth rate, per implanted embryo, was higher in twin than in singleton pregnancies: 83% compared with 76% (odds ratio 1.53, 95% confidence interval 1.24-1.88; P<.001). There were significant differences between the observed outcomes in twin pregnancies and those expected assuming no interaction between embryos (P<.001). The number of double births was higher than expected (71.9% observed compared with 57.7% expected), whereas single births were lower to a similar extent (22% observed compared with 36.5% expected). In contrast, observed and expected double losses were similar (6.1% observed compared with 5.8% expected). Although the overall rate of miscarriage was higher for women aged 34 years and older, the difference in live birth rate between twin and singleton pregnancies was 2.4-fold higher than in younger women. CONCLUSION:The higher live birth rate occurring in twin pregnancies can be accounted for by assistance, whereby some embryos that would fail as singletons survive in a twin pregnancy when implanted along with a fit sibling. This effect is more pronounced in older mothers.
journal_name
Obstet Gynecoljournal_title
Obstetrics and gynecologyauthors
Miró F,Vidal E,Balasch Jdoi
10.1097/AOG.0b013e31823bf978subject
Has Abstractpub_date
2012-01-01 00:00:00pages
44-9issue
1eissn
0029-7844issn
1873-233Xpii
00006250-201201000-00008journal_volume
119pub_type
杂志文章abstract：BACKGROUND:The effect of gonadotropin-releasing hormone agonist (GnRHa) on uterine arteriovenous malformations (AVM) is not well known. CASE:A 37-year-old woman with a previous cesarean was diagnosed as having a uterine AVM after a spontaneous abortion with massive vaginal bleeding. The AVM decreased in size from 5.1 ...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：10.1097/01.AOG.0000191584.28717.2c
更新日期：2006-09-01 00:00:00
abstract：BACKGROUND:Spectral Doppler ultrasound, an important diagnostic tool for the functional assessment of various organs, as yet has no major use in prenatal diagnosis due to the conventional technique's limitation of analyzing only one site at a time. Our aim was to develop a new modality that shows simultaneous studies o...
journal_title：Obstetrics and gynecology
pub_type： 临床试验,杂志文章
doi：
更新日期：1998-08-01 00:00:00
abstract：:An increase in cocaine abuse by pregnant women has been associated with a range of maternal/fetal cardiovascular complications. Intracerebral hemorrhage has been reported as a cocaine-related complication, but has not previously been associated with pregnancy. We report a case of cocaine-associated intracerebral hemor...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：
更新日期：1989-03-01 00:00:00
abstract：:One hundred patients undergoing pelvic exenteration (total 69, anterior 13, posterior 18) at the University of Michigan Medical Center from 1964-1984 are reported. All patients were followed for at least 5 years or until time of death. The overall cumulative survival was 66% at 3 years and 61% at 5 years. The age of t...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：
更新日期：1989-12-01 00:00:00
abstract：OBJECTIVE:To determine if scores from first attempts at the United States Medical Licensure Examination step 1 correlated with obstetrics-gynecology examination scores and identified students at risk of failure. METHODS:All students in obstetrics-gynecology clerkships at the University of Illinois at Chicago from July...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：10.1016/s0029-7844(99)00477-9
更新日期：1999-12-01 00:00:00
abstract：:Multifetal pregnancy reduction has been suggested as a strategy to improve pregnancy outcome in grand multiple gestations of three or more fetuses. We prospectively investigated multifetal pregnancy reduction in 13 women with triplet pregnancies in the first trimester following ovulation induction, in vitro fertilizat...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：
更新日期：1991-09-01 00:00:00
abstract：BACKGROUND:Twin reverse arterial perfusion, as with acardiac fetuses, is a rare complication of multifetal pregnancy. Prognosis of the donor twin is guarded because of the high risk of cardiac failure, polyhydramnios, and preterm delivery. CASE:A 40-year-old woman, gravida 4, para 3, was diagnosed at 19 weeks' gestati...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：10.1016/s0029-7844(00)01042-5
更新日期：2000-11-01 00:00:00
abstract：OBJECTIVE:To determine the cure rate of urge incontinence after Burch colposuspension in patients with mixed incontinence diagnosed urodynamically, to determine if cure rates were different when the onset of urge symptoms antedated or postdated the symptoms of stress incontinence, and to propose appropriate preoperativ...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：10.1016/s0029-7844(97)00550-4
更新日期：1998-01-01 00:00:00
abstract：:The systolic/end-diastolic ratio (S/D) and pulsatility and resistance indices were calculated before and after diagnostic cordocentesis in 46 fetuses, after 19 intravascular transfusions in eight fetuses, and on two occasions 45 minutes apart in eight controls. The fetus was paralyzed with pancuronium (0.3 mg/kg sonog...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：
更新日期：1989-02-01 00:00:00
abstract：OBJECTIVE:To evaluate the feasibility of examining the fetal ear with three-dimensional ultrasound. METHODS:In 125 pregnancies between 19 and 38 weeks of gestation, fetal ears were evaluated by three-dimensional ultrasound. The volume images with surface rendering were analyzed to depict the morphology, lying axis, or...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：10.1016/s0029-7844(98)00021-0
更新日期：1998-04-01 00:00:00
abstract：:Intrauterine retention of fetal bone is a rare complication of abortion that can cause secondary infertility by an unknown mechanism. We report such a case in which menstrual fluid prostanoids were measured to elucidate the possible pathophysiology. The pattern of prostanoid increases was similar to that seen in intra...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：
更新日期：1990-03-01 00:00:00
abstract：:The histories of 386 patients with untreated hydatidiform mole were reviewed to define the clinical aspects of accompanying theca lutein cysts. These cysts occurred in 102 patients (26.4%), with three patients experiencing cyst-related complications. Mean cyst size at diagnosis was 7.3 cm (3-20 cm), and did not correl...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：
更新日期：1988-08-01 00:00:00
abstract：OBJECTIVE:We describe the current state of prevention of neonatal group B streptococcal infections and present recent advances toward the development of a maternal vaccine for prevention of this disease. DATA SOURCES:We used a MEDLINE search of the Index Medicus from 1976-1992 for articles regarding group B streptococ...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章,评审
doi：
更新日期：1992-08-01 00:00:00
abstract：OBJECTIVE:To hypothesize that higher intake of docosahexaenoic acid, an n-3 long chain polyunsaturated fatty acid, would increase duration of gestation and birth weight in US women. METHODS:This was a randomized, double-blind, controlled, clinical trial. Subjects were enrolled in an ambulatory clinic where they receiv...
journal_title：Obstetrics and gynecology
pub_type： 临床试验,杂志文章,随机对照试验
doi：10.1016/s0029-7844(02)02585-1
更新日期：2003-03-01 00:00:00
abstract：:: Accurate dating of pregnancy is important to improve outcomes and is a research and public health imperative. As soon as data from the last menstrual period, the first accurate ultrasound examination, or both are obtained, the gestational age and the estimated due date should be determined, discussed with the patien...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章,评审
doi：10.1097/01.AOG.0000454932.15177.be
更新日期：2014-10-01 00:00:00
abstract：OBJECTIVE:To evaluate the feasibility of the detection of ureteral jets into the bladder in obstetric-gynecologic patients using transvaginal color Doppler ultrasound. METHODS:Fifty-two women were recruited and categorized into four groups: 1) 20 normal nonsurgical, 2) 17 post-cesarean delivery, 3) 12 post-total abdom...
journal_title：Obstetrics and gynecology
pub_type： 临床试验,杂志文章
doi：10.1016/s0029-7844(96)00373-0
更新日期：1997-01-01 00:00:00
abstract：BACKGROUND:Traditional methods of exchange of research information may not be rapid enough, especially for international multicenter studies or when discussing controversial issues such as the value of fetal monitoring. The Internet is a useful tool that provides numerous opportunities for immediate communication withi...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：10.1016/s0029-7844(99)00569-4
更新日期：2000-02-01 00:00:00
abstract：:The ovarian remnant syndrome is one of the least recognized and least discussed complications of oophorectomy. The most common presentation is pelvic pain with a pelvic mass. To prevent the condition, the ureters should be mobilized and laterally displaced during oophorectomy, and the pelvic side wall and cul-de-sac p...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：
更新日期：1979-08-01 00:00:00
abstract：OBJECTIVE:To assess the relationship between preeclampsia or eclampsia and stroke, myocardial infarction (MI), subsequent cardiovascular outcomes, and long-term survival. METHODS:Using the Myocardial Infarction Data Acquisition System in New Jersey (1994-2009), we analyzed cardiovascular outcomes in women with and wit...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：10.1097/AOG.0b013e31826ae78a
更新日期：2012-10-01 00:00:00
abstract：:Thirty-six patients with menorrhagia were treated with a technique for laser destruction of the endometrium in which the end of the fiberoptic guide of the Nd:Yag laser is not allowed to come in contact with the endometrium. The results were excellent in 93.9% of the 33 patients followed over three months. Amenorrhea ...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：
更新日期：1987-04-01 00:00:00
abstract：OBJECTIVE:To estimate an institution's specific fetal loss rate after a second-trimester genetic amniocentesis. METHODS:This is a retrospective cohort study using our prenatal diagnosis database for all pregnant women presenting for care between 1990 and 2006. We compared the fetal loss rate in women who underwent amn...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：10.1097/AOG.0b013e318162eb53
更新日期：2008-03-01 00:00:00
abstract：OBJECTIVE:To describe causes, courses, complications, and outcomes of patients with pregnancy-associated acute respiratory distress syndrome (RDS). METHODS:Twenty-eight women with ARDS during pregnancy or within a week postpartum formed the study population. Eight cases had been reported previously. Charts were abstra...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：10.1016/s0029-7844(00)01231-x
更新日期：2001-05-01 00:00:00
abstract：OBJECTIVE:To evaluate whether prophylactic dronabinol, a synthetic tetrahydrocannabinol, reduces pain during medical abortion. METHODS:We conducted a randomized, double-blind, placebo-controlled trial of women undergoing medical abortion with mifepristone and misoprostol up through 70 days of gestation. All participan...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章,随机对照试验
doi：10.1097/AOG.0000000000003850
更新日期：2020-06-01 00:00:00
abstract：:A case of primary endodermal sinus tumor (EST) of the endometrium in a 28-year-old woman is described. EST has been reported to arise in several extragonadal sites, but to the authors' knowledge this is the first documented instance of origin in the endometrium. The histologic study is verified by the detection of alp...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：
更新日期：1980-09-01 00:00:00
abstract：OBJECTIVE:To assess the risks of congenital varicella syndrome and other birth defects in offspring of women who inadvertently received varicella vaccine during pregnancy or within 3 months of conception. METHODS:Pregnant women inadvertently exposed to varicella vaccine, reported voluntarily, were enrolled in the Preg...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：10.1016/s0029-7844(01)01384-9
更新日期：2001-07-01 00:00:00
abstract：:In an effort to improve maternal and fetal outcome in patients laboring with thick meconium, 85 patients presenting with thick meconium were randomized to receive either amnioinfusion with 1000 mL normal saline initially and every 6 hours until delivery, or routine care. Meconium was discovered on initial examination ...
journal_title：Obstetrics and gynecology
pub_type： 临床试验,杂志文章,随机对照试验
doi：
更新日期：1989-04-01 00:00:00
abstract：OBJECTIVE:To address the evolving trends in the choice of transabdominal or transcervical chorionic villus sampling (CVS) at a teaching hospital and to evaluate the influence of gestational age on the approach chosen. METHODS:We analyzed our CVS data base, which contained information from 1986-1991. The proportions of...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：
更新日期：1992-09-01 00:00:00
abstract：BACKGROUND:Women with Lynch syndrome or hereditary nonpolyposis colorectal carcinoma (HNPCC) have a 40-60% lifetime risk of endometrial cancer and a 7-12% lifetime risk of ovarian cancer. Risk-reducing surgery, including hysterectomy and bilateral salpingo-oophorectomy (BSO), is currently recommended once child bearing...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：10.1097/AOG.0b013e3181b6f4f9
更新日期：2010-02-01 00:00:00
abstract：:We examined the release in vitro of tumor necrosis factor-alpha (TNF-alpha) by peritoneal macrophages and peripheral blood monocytes following incubation with toxic shock syndrome toxin-1 (TSST-1). We obtained peritoneal macrophages from 22 women at laparoscopy and peripheral blood monocytes from four healthy women du...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：
更新日期：1991-08-01 00:00:00
abstract：:Six patients with pure nonmosaic 46,XY gonadal dysgenesis (XY GD) and histocompatibility H-Y antigen titers in the normal male range (H-Y+) are presented. Clinical characteristics included a female phenotype, masculine skeletal characteristics, signs of virilization, and primary amenorrhea. All individuals had unambig...
journal_title：Obstetrics and gynecology
pub_type： 杂志文章
doi：
更新日期：1981-07-01 00:00:00
