The Fertility Center

A blog about fertility issues, treatments and trends from the specialists at Greenwich Fertility.

July 24, 2018

Non-viable Pregnancies Explained

By Barry R. Witt, M.D.

There are many reasons why a pregnancy may be diagnosed as a non-viable. From a clinical perspective, a viable pregnancy is one that has evidence for continued growth and development, and is characterized by the presence of measurable fetal heart activity. The usual end result of a viable pregnancy is the birth of a baby with a high chance for survival. A non-viable pregnancy is one in which the embryo or fetus has no evidence of fetal heart activity and has no chance of being born alive. If a doctor diagnoses your pregnancy as nonviable, it can be very overwhelming and sad.

Here are some common reasons for nonviable pregnancies: 

Chemical pregnancy

This term is used to describe a very early miscarriage, which occurs before the fifth week of gestation and well before the fetus can be visibly detected on an ultrasound. This occurs because the fertilized egg had some sort of chromosomal abnormality that made it non-viable from the start. A chemical pregnancy affects as many as 75 percent of all pregnancies. 

Anembryonic gestation

This is also known as a blighted ovum and happens when a fertilized egg attaches itself to the uterine wall, but the embryo does not develop. This occurs within the first trimester, often before a woman knows she is pregnant. Chromosome abnormalities usually result in a natural miscarriage.  In some cases, the miscarriage does not occur on its own and either medication is given to induce a miscarriage, or a surgical procedure known as a “D and C” may be performed. A blighted ovum is the cause of about 50% of first trimester miscarriages.

Missed abortion

This is similar to a blighted ovum but typically occurs later, after development of the embryo has occurred, and absent fetal heart activity is documented on an ultrasound examination, but a natural miscarriage has not yet happened. This also usually occurs within the first trimester and most often results from chromosomal abnormalities.  In some cases, the miscarriage does not occur on its own and either medication is given to induce a miscarriage, or a surgical procedure known as a “D and C” may be performed. 

Ectopic pregnancy

This occurs when the fertilized egg attaches itself in a place other than inside the uterus. Almost all ectopic pregnancies occur in the fallopian tubes. The fallopian tubes are not designed to hold a growing embryo and the fertilized egg cannot develop properly and must be treated, either medically or surgically. An ectopic pregnancy happens in 1 out of 50 pregnancies.

Molar pregnancy

This is an abnormality of the placenta caused by a problem when the egg and sperm join together at fertilization. Molar pregnancies rarely involve a developing embryo, and the growth of this abnormal placental material is rapid compared to the normal fetal growth. It has the appearance of a large and random collection of grape-like cell clusters. In the US, approximately 1 out of 1,000 pregnancies is a molar pregnancy.

If you are experiencing issues with conceiving, contact the fertility specialists at Greenwich Fertility today for a consultation!

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