During the first trimester, placenta separation in early pregnancy is difficult to diagnose because the placenta is very small. Separation, also called "placental abruption," is usually diagnosed after the twentieth week. Placental abruption in the first trimester can be a temporary problem, or it can lead to a miscarriage. Symptoms to watch for include vaginal bleeding and abdominal pain.
Purpose of the Placenta
Placenta bleeding in the first trimester can be linked to placental abruption. The placenta is a sac of blood vessels and other tissues. It attaches to the wall of the uterus and passes fluid, oxygen, and nutrients from mother to baby through the umbilical cord. The placenta also makes hormones that are important for a healthy pregnancy. Normally, the placenta does not separate from the uterine wall until after the baby is born.
Sometimes, the placenta begins to tear away from the uterus before the pregnancy reaches full term. The medical term for this is "placental abruption" or "abruptio placentae." When doctors talk about placental abruption, they are referring to placental separation that occurs in mid-to-late pregnancy, after the twentieth week. However, in some cases it's possible to see separation earlier. If the placenta separates entirely, the baby will not get the oxygen, fluids, or nourishment he or she needs to survive.
Common symptoms of placental separation include vaginal bleeding and abdominal pain, but vaginal bleeding does not always occur. Depending on where the separation is located, the bleeding may be contained entirely within the uterus. If the amount of blood is small, the problem may go away without any lasting problems. Extensive separation is likely to lead to miscarriage.
Recognizing Placenta Separation in Early Pregnancy
When bleeding occurs during a pregnancy, especially near or after week twenty, placental separation should be considered. An ultrasound exam may be needed for diagnosis. To get a clearer picture, a transvaginal ultrasound, in which the ultrasound probe is inserted into the vagina, may be used.
In some cases, it won't be possible to make a firm diagnosis. Very early in pregnancy, ultrasound may not show enough detail. If the amount of blood is small, it may be difficult to distinguish it on the ultrasound from normal variations within the placenta. Although an early miscarriage could be due to placenta separation in early pregnancy, it could have many other causes. Often, the reason for miscarriage is never discovered.
Other Causes of Bleeding in Early Pregnancy
Vaginal bleeding has several possible causes. The placenta may attach low in the uterus, so that the baby presses down on it. This can lead to spotting and bleeding. Sometimes the placenta will shift higher in the uterus as the pregnancy progresses and the bleeding will stop. Other possible causes of bleeding include implantation bleeding, vaginal injury, infection, and ectopic pregnancy.
Treatment for Placenta Separation in Early Pregnancy
When bleeding occurs early in pregnancy, the doctor may recommend closer monitoring to watch for signs of miscarriage. There's some evidence that bleeding behind the placenta, which can lead to partial placenta separation in early pregnancy, can go away on its own without harming the baby. Frequent ultrasound exams can help reveal how the baby is growing and, if the placenta separation is visible, whether there has been important damage to the placenta. If the placenta does not work properly, the baby's growth will be impaired.
Severe bleeding sometimes happens with placental abruption in middle or later pregnancy. In these cases, emergency treatment is directed at preventing the mother from going into shock. The baby's vital signs will be monitored and an emergency C-section may be necessary. With severe placenta separation early in pregnancy, around the twentieth week for example, there may be no way to save the fetus.
Will It Happen Again?
A woman who has had a placental abruption is at increased risk of it happening again in a later pregnancy. The chance is about one in ten. However, since placenta separation in early pregnancy isn't always diagnosed and isn't well-understood, it's hard to determine the exact risk of an early separation happening again.
Sometimes, placental abruption is due to an underlying problem with the woman's health. High blood pressure, smoking, and drug abuse all increase the risk. It's possible that these problems also increase the risk of separation earlier in pregnancy.