What Is Viable/ Non-viable Pregnancy?

What Is Viable Non-viable Pregnancy

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You are told to be extremely careful in the early weeks of your pregnancy. That’s because the initial stages of the pregnancy are considered crucial for the viability of fetus or its ability to survive. As an expectant mother, you should be familiar with this concept.

If you are eager to know about it, this MomJunction post is for you. Here, we tell you what a viable and non-viable pregnancy is, how and when it is determined, what makes a pregnancy non-viable, and tips for managing it.

Viable Pregnancy

A viable pregnancy is when the fetus reaches a stage where it is capable of surviving outside the womb, under normal conditions. The viability of a pregnancy is based on many factors, such as the gestational age, birth weight, technological interventions, and fetal sex (1) (2).

Ideally, doctors should know if the fetus is viable by 22-25 weeks of gestation, based on their clinical judgments. But not every doctor can diagnose correctly at this stage of pregnancy. Also, every pregnancy is different, which means there are some other determining factors as well.

When Is The Viability In Pregnancy Determined?

Ideally, doctors will know if the fetus is viable by 22-25 weeks of gestation, based on their clinical judgments. However, as every pregnancy is different, the viability of a pregnancy can be determined only after examining the mother and the fetus. Factors on which the viability depends on are (2) (3):

  • Mother’s health: Age, health conditions, previous miscarriages, and the overall health of the woman affects the viability of the pregnancy
  • Chromosomal abnormalities: In many cases, the study of chromosomal abnormalities remains unknown. Hence, viability might not be determined sooner.
  • Availability of advanced neonatal care: Some hospitals may not have advanced technology to diagnose if the woman has preeclampsia, while some may have the right technology to detect the condition in the early weeks of pregnancy. Depending on the infrastructure and technology used by the hospital, it could either be a timely diagnosis or too late to determine if the pregnancy is viable or not.
  • Fetal sex: A few studies suggest that the male fetus’ mortality rate was higher than that of the female fetus. This, in turn, affects the viability of the pregnancy.

These factors could make determining the viability at around 24 weeks difficult, thus delaying the diagnosis. But thanks to the improvements in medical technology, doctors can determine the viability of the pregnancy sooner than later.

When a pregnancy is not viable, it becomes non-viable. Find out more about it next.

[ Read: Amazing Pregnancy Facts ]

Non-Viable Pregnancy

A pregnancy is non-viable when there is hardly any chance of the baby’s survival or when the fetus is not developing. The result could be an expelled fetus or a living fetus but with limited or no chance of surviving once it is outside the uterus.

In the early weeks, a non-viable pregnancy could lead to an abortion or a miscarriage. Bleeding and pain are the typical symptoms of a non-viable pregnancy. Further diagnosis via pelvic ultrasonography and serum hCG measurement are performed to confirm it (4).

A non-viable pregnancy could be due to causes, which we see in the next section.

Causes Of Non-Viable Pregnancy

Various factors could be responsible for a non-viable pregnancy. Some of them are explained below.

  1. Chemical pregnancy: This kind of pregnancy ends quite early during the first trimester. It happens when the fetus is expelled or dies just after the conception. A chemical pregnancy is also non-viable when the test shows positive results, but there is no gestational sac or embryo development (5).
  1. Molar pregnancy: In this type of pregnancy, the tissue turns into an abnormal growth or tumor in the uterus instead of becoming a fetus. The symptoms include discomfort in the pelvis, vaginal bleeding, vaginal discharge, and signs that indicate hyperthyroidism (6).
  1. Ectopic pregnancy: When the implantation occurs outside the uterus, there is no chance of a viable pregnancy. Irrespective of the type of ectopic pregnancy, including cervical, interstitial, or ovarian, the result is non-viable (7).
  1. Blighted ovum: It is a cause of miscarriage or early pregnancy cause. Other terms for this condition are empty sac and anembryonic pregnancy that occur when gestational sac and placenta are there, but the attached embryo fails to develop (8).
  1. Congenital anomalies: The WHO states that congenital malformations are among the leading causes of neonatal mortality. However, the laws regarding abortion due to this factor differ across the world. While some don’t allow abortion and encourage the women to carry on with the pregnancy, a few countries keep in mind the psychological condition of the mother and make a decision (9).
  1. Others: Some other causes of non-viable pregnancy include a premature baby, baby with no heartbeat, and abnormal chromosome count.

In the next section, we talk about the methods to determine the viability of the fetus.

Early Viability Scan

Early viability scan is done between six and ten weeks. It checks the number of fetuses in the womb, heartbeat, and if everything is normal inside the womb. This scan is suggested for pregnant women who are experiencing bleeding or pain and for those who have had a miscarriage previously. Besides an ultrasound, a transvaginal scan may also be recommended to get a better image (10).

The pregnancy is said to be viable if (11):

  1. The scan detects a gestational sac with a fetal pole (thickening of yolk sac) along with cardiac activity
  1. The crown-to-rump length that is > 6mm
  1. The gestational sac, yolk sac, and an embryo are visible in the scanned image

All these can be detected around five to six weeks of pregnancy. If any of the factors mentioned above are not entirely met, it could suggest a non-viable pregnancy. Find out how to determine that in the next section.

[ Read: Chemical Pregnancy: Causes, Signs And Symptoms ]

Factors Determining Non-Viable Pregnancy

The following factors determine non-viable pregnancy or pregnancy loss. These are checked via a scan (4).

  • No heartbeat, and the CRL ≥ 7mm
  • No embryo and the mean sac diameter ≥ 25mm
  • No embryo and heartbeat after 11 days of the scan, which showed yolk sac and gestational sac
  • No embryo and heartbeat after two weeks of the scan, which showed a gestational sac but not a yolk sac

Some findings that could suggest a risky and non-viable pregnancy include:

  • No embryo and mean sac diameter between 16mm and 22mm
  • No heartbeat and CRL < 7mm
  • Empty amnion
  • Six weeks after the period, there is no embryo
  • A larger yolk sac, which is greater than 7mm
  • Small gestational sac
  • No embryo with a heartbeat between seven and 13 days of the scan that earlier showed the gestational sac but not the yolk sac
  • No embryo with a heartbeat between seven and ten days of the scan that previously showed a yolk sac and gestational sac

A non-viable pregnancy means there is no chance of the baby being born alive or surviving after it is born. That does not, however, mean that you cannot get pregnant again.

Are There Any Non-Viable Pregnancy Management Options?

Yes. You can follow these non-viable pregnancy management options for a chance to get pregnant even after a non-viable pregnancy or a loss of pregnancy.

  1. Expectant management: This is a natural method wherein you allow miscarriage naturally, without any medical intervention and use of medicines or surgery. However, if the miscarriage doesn’t happen, then the professional will examine you and decide the next step (12).
  1. Medicine: A medicine called misoprostol is prescribed for some women to terminate a non-viable pregnancy. Women may experience heavy bleeding or pain in this method. In case the pain becomes severe, consult the doctor (13).
  1. Surgery: A simple surgical procedure known as dilation and curettage or D and C is performed to remove the non-viable fetus from the uterus. The procedure is done in just a few minutes. And after that, your doctor will explain what needs to be done next (14).

Is It Possible To Have A Non-Viable Pregnancy But No Miscarriage?

Yes, a non-viable pregnancy without a miscarriage is termed as a missed miscarriage or silent miscarriage. It could happen just after implantation, which is around six to ten weeks of pregnancy. There could be no bleeding or cramps or any other signs of pregnancy. However, the ultrasound could show an empty sac or an embryo without a heartbeat or embryo with no development (15).

In such a case, contact your doctor for further diagnosis and guidance.

[ Read: What Is Ectopic Pregnancy ]

Being informed about the essential pregnancy concepts will help you to make the right decision in time. In case you have any doubts about your health or the fetus’ condition early in the pregnancy, check with your doctor. Being careful during the early pregnancy weeks and keeping track of your health is essential to ensure healthy and viable pregnancy.

Do you have any experiences to share? Let us know in the comment section below.

References:

1. G. H. Breborowicz; Limits of fetal viability and its enhancement; Early Pregnancy (2001)
2. The Science of “viability”; Later Abortion Initiative (2018)
3. Viability of extremely premature babies; British Pregnancy Advisory Service
4. P. M. Doubilet, C. B. Benson, T. Bourne, and M. Blaivas; Diagnostic Criteria for Nonviable Pregnancy Early in the First Trimester; the New England Journal of Medicine (2016)
5. C. A. Schreiber, M, Sammel, S. L. Hillier, and K. T. Barnhart; A Little Bit Pregnant: Modeling How the Accurate Detection of Pregnancy Can Improve HIV Prevention Trials; American Journal of Epidemiology (2009)
6. Molar Pregnancy; Penn Medicine Lancaster General Health
7. P. L. Edward, S. Bhatt, and V. S. Dogra; Diagnostic Clues of Pregnancy; Radiographics
8. Understanding Blighted Ovum; UC San Deigo Health
9. D. C. Sala and A. R. Abrahao; Obstetric complications in pregnancies with fetal anomalies incompatible with neonatal survival; scielo.br
10. Viability Scan; The Fetal Medicine Center
11. C. Bottomley et al.; The optimal timing of an ultrasound scan to assess the location and viability of an early pregnancy; Human reproduction (2009)
12. Schaefer and D. Lynn; Unrecognised loss: how to best support women experiencing miscarriage; The University of Arizona (2018)
13. K. A. Zikopoulos et al.; Early pregnancy termination with vaginal misoprostol before and after 42 days gestation; Human Reproduction (2002)
14. Dilation and Curettage (D and C); Johns Hopkins Medicine
15. What is miscarriage?; Planned Parenthood

 

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