Disease relevance of Pregnancy, Multiple

• Those who do not respond to clomiphene citrate usually receive gonadotrophin treatment which is labour-intensive, expensive, and associated with an increased risk of multiple pregnancies and ovarian hyperstimulation syndrome [1].
• Clinical features associated with an increased risk of multiple pregnancies were the presence of polycystic ovary syndrome and secondary infertility [2].
• Ovulation induction with pulsatile gonadotropin-releasing hormone achieves high ovulatory and pregnancy rates in hypogonadotropic hypogonadism while limiting the occurrence of ovarian hyperstimulation and multiple pregnancy [3].
• Although mean fundal height is substantially greater in twin than singleton pregnancies, the value of the technique to detect multiple pregnancies may be limited because combined birth-weight is less and the frequency of SGA fetuses is greater in undiagnosed than in diagnosed twin pregnancies [4].
• Recurrent ACTH-independent Cushing's syndrome in multiple pregnancies and its treatment with metyrapone [5].

Psychiatry related information on Pregnancy, Multiple

• CONCLUSION(S): Over the years, ART therapies have steadily become more effective, with notable reductions in multiple pregnancies, the ability to avoid laparoscopy (for egg retrieval and in some cases tubal transfers), and effective therapy for serious sperm, egg, and uterine problems, none of which was true in the early years [6].

High impact information on Pregnancy, Multiple

• However, increasing total numbers of follicles and increasing peak serum estradiol concentrations correlated significantly with an increasing risk of high-order multiple pregnancy (P<0.001), as did younger age (P=0.008) [7].
• Preservation of embryos for a limited time allows fewer embryos to be replaced on several different occasions and thus the problems of multiple pregnancy can be minimized, the effectiveness of a single IVF procedure increased and embryo replacement in adverse maternal conditions avoided [8].
• The pregnancy and multiple pregnancy rates after stimulation with clomiphene alone or with human menopausal gonadotropin were comparable, but oocyte pickup based on a knowledge of the duration of the endogenous rise in luteinising hormone, rather than 36 h after administration of human chorionic gonadotropin, increased the pregnancy rate [9].
• Moreover, there is an increasing trend to culture embryos for longer periods of time before uterine transfer to identify the "best" embryos for transfer and to minimize multiple pregnancies [10].
• Since pRb-deficiency results in embryonic lethality, we transplanted pRb-null mammary anlagen into wild hosts. pRb-deficient mammary epithelia were capable of functional differentiation in term animals and they regenerated a differentiated gland even after multiple pregnancies [11].

Chemical compound and disease context of Pregnancy, Multiple

• Until the results of such a trial are available we advocate the use of nifedipine in case of preterm labor, especially in a patient with diabetes mellitus, ruptured membranes, cardiac disease or multiple pregnancy, in order to avoid the characteristic side effects of beta-mimetics [12].
• Moreover, although the overall incidence of hypotension was not different (multiple pregnancy; 65% vs 58% in singletons), ephedrine (5.4 +/- 5.3 mg vs 10.7 +/- 13.8 mg; P < 0.05) and additional fluid requirements during onset of the block (4.3 +/- 1.7 mL/kg vs 5.3 +/- 2.6 mL/kg; P = 0.03) were less than in singletons [13].
• Reasons for exclusion were: refusal, antepartum haemorrhage, cardiac disease, breech presentation, multiple pregnancy, intrauterine death, and, after May 1986, ritodrine given two hours before delivery, anticoagulant treatment, and any condition needing a particular management of third stage [14].
• The additive effects of adjunctive treatments such as weight reduction, ovarian drilling, and clomiphene and metformin therapy may result in an increased incidence of higher-order multiple pregnancy and women need to be counseled about this risk [15].
• However, the remaining risk of ovarian hyperstimulation syndrome, the still low implantation rates, the unacceptably high rates of multiple pregnancies and the daily parenteral administration of medications do not constitute the features of a patient-friendly procedure [16].

Biological context of Pregnancy, Multiple

• These results suggest that combined induction treatment by CC and HMG as described offers a means of achieving low rates of multiple pregnancies a known complication in the induction of ovulation [17].
• CONCLUSIONS: Single embryo transfer significantly reduces the risk of multiple pregnancy, but also decreases the chance of live birth in a fresh IVF cycle [18].
• Women with anovulation due to polycystic ovary syndrome are likely to develop multiple follicles during gonadotrophin therapy and therefore have a high risk of multiple pregnancy [19].
• Factors other than the initial number of embryos, maternal age, and IVF technique, such as embryo quality or uterine environment, might be involved in the outcome of multiple pregnancies in assisted reproductive technology procedures [20].

Anatomical context of Pregnancy, Multiple

• To control the risk of multiple pregnancies, the number of gametes (GIFT) or embryos (IVF, ZIFT) replaced is limited to three [21].
• CONCLUSION: Blastocyst transfer increases implantation rates and PRs in patients with multiple failed IVF cycles, without increasing the risk of multiple pregnancy [22].
• Selective oocyte retrieval is a new approach to ovarian hyperstimulation (OHS) that prevents side effects of OHS and multiple pregnancies by puncturing most of the ovarian follicles 35 hours after hCG administration as in an IVF program [23].
• Elective single-embryo transfers and the decrease of iatrogenic multiple pregnancies in IVF remain dependent on better prognostic tools for the appropriate selection of patients, gametes, and zygotes [24].
• The concentration of alpha-fetoprotein (AFP) was determined in paired umbilical cord and maternal sera in 42 multiple pregnancies [25].

Associations of Pregnancy, Multiple with chemical compounds

• In addition, there is a significant risk of multiple pregnancy with CC, compared with natural cycles [26].
• Gestational glucose intolerance in multiple pregnancy [27].
• However, in the absence of progesterone or when stretch is excessive, as in multiple pregnancy, it may provoke the onset of labour [28].
• Three patients with hypothalamic amenorrhea who had previously had multiple pregnancies following gonadotropin therapy were treated with subcutaneous pulsatile gonadotropin-releasing hormone (GnRH), administered by a portable pump [29].
• These data suggest that (i) the circulating levels of hCG, OE2 and progesterone increase with conceptus number; (ii) placental tissue does not remain active following fetal reduction; and (iii) the rate of steroid metabolism is increased in multiple pregnancy and remains elevated following fetal reduction [30].

Gene context of Pregnancy, Multiple

• Plasma POMC was significantly higher in multiple pregnancies with very high levels in three triplet-bearing mothers: 671, 941, and 1731 U/ml at 31, 33 and 32 weeks, respectively [31].
• OBJECTIVE: We tested the hypothesis that multiple pregnancies would be associated with altered expression of the following three groups of proteins that are key regulators of myometrial function: (i) Gsalpha, (ii) connexins-43 and 26, and (iii) prostanoid EP1, EP3, and EP4 receptors [32].
• No similar stagnation of endometrial thickness and no effects of mid-cycle HCG administration on endometrial thickness, the implantation rate and the number of multiple pregnancies were found in women with high endogenous LH [33].
• PHA treatment cycles were characterized by the reestablishment of a normal endocrine pattern, almost no dose-related endocrine differences, elevated ovulatory (93%) and conception rates (23%), and no multiple pregnancies [34].
• Implantation (gestational sacs/embryo transferred) and multiple pregnancy (multiple gestations/ pregnant recipient) rates were slightly higher in relaxin-treated recipients compared to vehicle-treated recipients [35].

Analytical, diagnostic and therapeutic context of Pregnancy, Multiple

• Due to increased maternal and fetal risks, there is a strong opinion in favor of single embryo transfer (SET) in order to reduce the high multiple pregnancy rate after IVF [36].
• IVF treatment, which involves ovarian stimulation, poses significant health problems such as ovarian hyperstimulation and is associated with a high incidence of multiple pregnancy and premature birth [37].
• Furthermore, the multiple pregnancy rate was markedly increased in the leuprolide group (44% versus 8%), suggesting that the improved pregnancy outcome with pituitary suppression was due primarily to higher oocyte and embryo quality [38].
• Since the ultimate goal for an IVF treatment is the birth of a healthy infant, an important issue for all kinds of assisted reproductive technologies (ART) must be the reduction or elimination of multiple pregnancies [39].
• The algorithm was validated by comparing the calculated pregnancy probability and multiple pregnancy probability with the actual outcome of 281 separate IVF/ICSI cases [40].

References