Publicação
Timing and mode of delivery in twins : the ongoing controversy
| Resumo: | Twins occur when more than one offspring is produced in the same pregnancy. They can result from one or several zygotes – Monozygotic (MZ) and Dizygotic (DZ) twins. DZ twins are always dichorionics (DC) with as many placentas and amniotic sacs as the number of fetuses. MZ twins can also be dichorionic (18-30%) or have only one placenta – monochorionic (MC). This last kind of twins might have one amniotic sac for each fetus (60-70%) – MC-DA twins, or only one amniotic sac for both fetuses – MCMA twins (1-2%). In our days, twin births represent 30‰ of all births in Portugal. Twin gestation is a high risk pregnancy whose successful outcome depends on timely diagnosis of several maternal or fetal problems. In this thesis, we try to establish the best sonographic measurements to identify twin pairs with an intertwin weight discordance >25%, we analyze the benefit of changes in BMI to mothers carrying DC twins, and we evaluate the risk factors and the outcomes of twin pregnancies with gestational diabetes mellitus. However the main goal of this work is to determine the optimal time of delivery for an uncomplicated twin gestation, the safety of labor induction and the puerperal morbidity of cesarean (CS) delivery in twins. Current recommendations suggest the optimal time of delivery for DC twins is at 37-38 wks, at 36-37 wks for MC-DA twins and at 32-34 wks for MC-MA twins. A vaginal delivery could be considered for vertex-vertex twins and vertex-non vertex twins, when the provider’s skills and experience allow, and is safe in MC-DA twins. Protocol for induction of labor used in singletons is applicable in twins and misoprostol is safe for labor induction. A Cesarean section is recommended in MC-MA, non - vertex presenting twins, when the second twin is ≥40% larger than the presenting twin and women with a uterine scar. Patients should receive thorough information about the risks of vaginal and CS deliveries and the vaginal route should be performed by a medical team with experience in obstetric maneuvers. |
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| Autores principais: | Simões, Helena Teresinha Fernandes, 1960- |
| Assunto: | Obstetrícia Gémeos Gravidez de gémeos Parto Teses de doutoramento - 2014 |
| Ano: | 2014 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | Twins occur when more than one offspring is produced in the same pregnancy. They can result from one or several zygotes – Monozygotic (MZ) and Dizygotic (DZ) twins. DZ twins are always dichorionics (DC) with as many placentas and amniotic sacs as the number of fetuses. MZ twins can also be dichorionic (18-30%) or have only one placenta – monochorionic (MC). This last kind of twins might have one amniotic sac for each fetus (60-70%) – MC-DA twins, or only one amniotic sac for both fetuses – MCMA twins (1-2%). In our days, twin births represent 30‰ of all births in Portugal. Twin gestation is a high risk pregnancy whose successful outcome depends on timely diagnosis of several maternal or fetal problems. In this thesis, we try to establish the best sonographic measurements to identify twin pairs with an intertwin weight discordance >25%, we analyze the benefit of changes in BMI to mothers carrying DC twins, and we evaluate the risk factors and the outcomes of twin pregnancies with gestational diabetes mellitus. However the main goal of this work is to determine the optimal time of delivery for an uncomplicated twin gestation, the safety of labor induction and the puerperal morbidity of cesarean (CS) delivery in twins. Current recommendations suggest the optimal time of delivery for DC twins is at 37-38 wks, at 36-37 wks for MC-DA twins and at 32-34 wks for MC-MA twins. A vaginal delivery could be considered for vertex-vertex twins and vertex-non vertex twins, when the provider’s skills and experience allow, and is safe in MC-DA twins. Protocol for induction of labor used in singletons is applicable in twins and misoprostol is safe for labor induction. A Cesarean section is recommended in MC-MA, non - vertex presenting twins, when the second twin is ≥40% larger than the presenting twin and women with a uterine scar. Patients should receive thorough information about the risks of vaginal and CS deliveries and the vaginal route should be performed by a medical team with experience in obstetric maneuvers. |
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