…..Let us now start to review how early pregnancy (the first trimester) is evaluated, especially in the case of bleeding.
…..The embryo produces a hormone called hCG very early in the pregnancy, and later the placenta also produces this hormone. Repeating or checking the levels of the hCG every 2 to 3 days is helpful when trying to assess the viability of an early pregnancy and to see if it is normal. At a certain hCG level (between 1200 to 1500), a pregnancy should be visualized by a transvaginal sonographic exam. When serial hormone levels are being followed, it is important to use the same laboratory or else there may be different test kits used at the specific lab, and so the results may not be accurate.
…..The hCG level should have a minimum rise of 50% every 2 days, and some practitioners consider a rise of 66% to better reflect a normal pregnancy. I was taught that the levels should double every 3 days, and this is the formula I have always used.
…..All pregnancies are different, and there is some variability in the rise of hCG in normal pregnancies. There are also some specific circumstances that affect this hormone’s levels:
- If the woman is dehydrated when a test is taken, and on the repeat test she drinks more, the test can be affected
- The level of hCG, which rises so dramatically early in the pregnancy, will begin to level off at about 8 weeks
- In twins and other multiple pregnancies, the numbers can have great variability especially if there is a problem with one of the pregnancies
…..There are a few common causes of bleeding in the first trimester:
- Spontaneous abortion
- Ectopic pregnancy
- Subchorionic hemorrhage
- Gestational trophoblastic disease (less common)
…..When we speak about miscarriages (spontaneous abortions), there are a few terms which are frequently used. An ultrasound and an examination will usually confirm the diagnosis:
- Threatened abortion (when vaginal bleeding occurs before 20 weeks of gestation, there is a viable pregnancy, and the woman has a closed cervix)
- Inevitable abortion (if there is a dilated cervix)
- Incomplete abortion (when a portion of the pregnancy has passed)
- Complete abortion (when all of the pregnancy tissue (products of conception) has passed)
…..Gestational trophoblastic disease is a much less common cause of vaginal bleeding early in a pregnancy. Some signs of this condition would be a pregnancy size larger than would be expected (based on routine dates), very high levels in a blood pregnancy hormone test (hCG), and severe nausea and vomiting. Here are some common terms that are encountered:
- Complete hydatidiform mole: A partial mole is formed when a sperm fertilizes an egg that has no nucleus. This is the most common type of this condition. On a sonogram, there may be many ovarian cysts seen or many cysts within the uterus.
- Partial mole: This arises when two sperm fertilize an egg. On a sonogram, there may be a sac with a fetus.
…..I would like to begin a review of one of the most common complications of early pregnancy, vaginal bleeding. This is the number one reason patients will have an emergency visit in the first trimester, and it is a cause of great anxiety to patients and their families. There are a few important facts you should be aware of:
- About 15% of recognized pregnancies will end in miscarriage
- 80% of miscarriages occur in the first trimester
- Trauma, smoking, excessive alcohol use, and advanced maternal age increase the risk of first trimester bleeding
- 25% of pregnant women will report first trimester bleeding or spotting
- 8% of pregnant women report heavy vaginal bleeding
- Of the patients who report bleeding, 75% will have 1 episode, 20% will have 2 episodes, and 10% will have 3 or greater episodes
- The amount of bleeding is the most significant predictor of an impending miscarriage
- Again, advanced maternal age is a significant risk factor for first trimester bleeding and subsequent miscarriage; 50% of pregnancies in women over 40 result in a miscarriage, with abnormal chromosomes in the fetus being a primary factor
- For women under the age of 35, the rate of a spontaneous miscarriage is 2%.