Ad
related to: causes of low lying placenta pregnancy 12 weeks ultrasound gender roles
Search results
Results from the WOW.Com Content Network
Besides placenta previa and placental abruption, uterine rupture can occur, which is a very serious condition leading to internal or external bleeding. Bleeding from the fetus is rare, but may occur with two conditions called vasa previa and velamentous umbilical cord insertion where the fetal blood vessels lie near the placental insertion site unprotected by Wharton's jelly of the cord. [11]
The pregnancy loss rate in pregnancies with confined placental mosaicism, diagnosed by chorionic villus sampling, is higher than among pregnancies without placental mosaicism. It may be that sometimes the presence of significant numbers of abnormal cells in the placenta interferes with proper placental function.
[8] [9] However, the case of intrauterine hematoma observed before 9 weeks of gestational age has been associated with an increased risk of miscarriage. [10] In one study women who complied with instructions for bed rest for the duration of bleeding had a lower rate of miscarriage and a higher rate of term pregnancy than non-compliant women.
Histopathology of placenta with increased syncytial knotting of chorionic villi, with two knots pointed out. The following characteristics of placentas have been said to be associated with placental insufficiency, however all of them occur in normal healthy placentas and full term healthy births, so none of them can be used to accurately diagnose placental insufficiency: [citation needed]
In those less than 36 weeks pregnant, corticosteroids may be given to speed development of the baby's lungs. [1] Cases that occur in early pregnancy may resolve on their own. [1] Placenta praevia affects approximately 0.5% of pregnancies. [5] After four cesarean sections, however, it affects 10% of pregnancies. [4]
As the pregnancy progresses, the placenta tissue surrounding the vessels over the cervix undergoes atrophy, and the placenta grows preferentially toward the upper portion of the uterus. This leaves unprotected vessels running over the cervix and in the lower uterine segment. This has been demonstrated using serial ultrasound.
Normally in the second half of pregnancy, one-third of fetal cardiac output is directed towards the placenta. This fraction is reduced to around one-fifth in the last few weeks of pregnancy, while the remaining umbilical blood is recirculated in the fetal body, corresponding with decreased fetal reserves of oxygen. [25]
The sex of the fetus may be discerned by ultrasound as early as 11 weeks' gestation. The accuracy is relatively imprecise when attempted early. [15] [16] [17] After 13 weeks' gestation, a high accuracy of between 99% and 100% is possible if the fetus does not display intersex external characteristics. [18]
Ad
related to: causes of low lying placenta pregnancy 12 weeks ultrasound gender roles