Non-Viable Pregnancies
Again, a non-viable pregnancy means that the baby has zero chance of surviving outside the womb. While there are strict medical guidelines for determining pregnancy viability, it is important that you are fully informed before moving forward with any medical procedure.
You’re much more likely to have a failed, or non-viable, pregnancy in the first trimester (the first 0-13 weeks of pregnancy)2. Any suspicion of a non-viable pregnancy should be discussed with your medical professional and all options explored before action of any kind is undertaken. A second opinion is always a good idea. While 10-20% of known pregnancies end in miscarriage3, there are other pregnancies that continue despite being non-viable and can potentially cause health risks. With that in mind, here are some of the most common causes of non-viability that may be detected through an ultrasound performed at 6 weeks gestation or later.
- No heartbeat. Keep in mind that if the gestational age of the pregnancy has not definitively been determined, it may be too early to detect a fetal heartbeat. Waiting a week or two and repeating the vaginal ultrasound may be in order. If a second ultrasound does not show a heartbeat, it could mean that you have miscarried or that the baby has died in utero. There could be a variety of reasons that the baby failed to thrive and develop. Consult with your medical professional regarding the need for a procedure known as dilation and curettage (D&C) or other method to ensure the safe and full expulsion of the fetus, placenta and pregnancy tissue from the uterus. During a D&C, the cervix is dilated and the contents of the uterus are removed using suction and/or a looped tool called a curette4.
- Ectopic pregnancy. This condition occurs when the fertilized egg implants outside of the uterus, most often in the fallopian tubes. An ectopic pregnancy affects 1% to 2% of all pregnancies and poses a significant threat to women of reproductive age. If left undiagnosed or untreated, the fetus can grow until it ruptures the fallopian tube, which will cause heavy internal bleeding in the abdomen and may lead to shock. It is the leading cause of maternal death during the first trimester of pregnancy and is responsible for 9% of pregnancy-related deaths in the United States5.
To prevent these life-threatening complications, the ectopic tissue must be removed using medication, laparoscopic or abdominal surgery. The method depends on your symptoms and when the ectopic pregnancy is discovered6.
- Anembryonic Gestation/Blighted Ovum. When a fertilized egg attaches to the uterine wall, it begins to develop a gestational sac around itself. In the case of anembryonic gestation, or blighted ovum, the gestational sac continues to grow, but the egg inside it does not, and it never develops into an embryo. This condition is believed to be the result of chromosomal abnormalities and often ends in miscarriage before or shortly after the woman becomes aware she is pregnant7.
If a miscarriage does not occur, the condition can be detected during an ultrasound that shows the gestational sac to be empty. At that point, your doctor may recommend waiting for a natural miscarriage to occur or suggest a D&C.
- Molar Pregnancy. This is a rare complication (1 in 1,000 pregnancies) that can present as either a complete or partial molar pregnancy. In a complete molar pregnancy, the placental tissue develops abnormally, becoming swollen and forming fluid-filled cysts that may appear like grapes on an ultrasound. A fetus does not form in this type of molar pregnancy because the egg that is fertilized is empty, meaning that the genetic material comes solely from the father’s sperm. A partial molar pregnancy, on the other hand, may contain both normal and abnormal placental tissue that forms simultaneously. A fetus may also form, but it is rarely able to survive because the abnormal tissue overtakes the fetus and/or because two sperm fertilize the same egg, thus providing two sets of male chromosomes, or two sets of the father's genetic material. If a doctor suspects a molar pregnancy, blood tests and an ultrasound will usually be ordered. If the pregnancy doesn’t end in miscarriage, other treatment options will be explored8.
In extremely rare instances, an embryo does develop and survive into the late weeks of a molar pregnancy, so while considered a non-viable pregnancy, it is always important to get conclusive evidence before moving forward. Women who are younger than 20 or older than 35 are at slightly higher risk of having molar pregnancies. There is also a chance that the molar pregnancy can develop into a cancerous tumor and spread beyond the uterus if not treated successfully9,10.