If You’ve Had Miscarriages Before, Don’t Skip PGD Testing

Miscarriage, or the spontaneous loss of a pregnancy before the 20th week of gestation, is a heartbreaking reality for many couples. Although the experience can be painful, traumatic, or even isolating, it’s not uncommon. 

An estimated 10-15% of known pregnancies — and by one estimate, as many as half of all pregnancies, including those that occur before a woman knows she’s even conceived — end in miscarriage. The vast majority of miscarriages happen in the first trimester, before the 12th week of pregnancy. 

Recurrent miscarriage, or the early loss of two or more clinical pregnancies, is also surprisingly common. If you’ve been devastated by multiple miscarriages, you may already know that you’re 40% more likely to have another miscarriage as you and your partner continue trying for a baby.  

What you may not realize, however, is that having a history of miscarriage doesn’t mean you can’t go on to have a successful pregnancy. Here’s how preimplantation genetic diagnosis (PGD) may be able to help you dramatically reduce your risk of early pregnancy loss — and increase your chances of delivering a healthy, full-term baby. 

What causes miscarriage?

Because there are a lot of misconceptions surrounding miscarriage, it’s important to understand why it occurs in the first place.   

While it isn’t always possible to determine the underlying cause of an individual miscarriage, researchers have a firm grasp on what can — and what cannot — lead to early pregnancy loss. 

Miscarriage is virtually never the result of a normal activity like exercise, working, or having sex. Most common medications, mild illnesses, and minor injuries don’t cause miscarriage either. 

So what can cause miscarriage? Early pregnancy loss can occur following a major injury or a very serious infection; it can also be the result of a chronic uncontrolled illness such as diabetes. Cervical insufficiency, uterine abnormalities, polycystic ovary syndrome (PCOS), and other significant gynecological problems can also play a role in miscarriage.

Most miscarriages happen because the fetus isn’t developing as it should. An estimated 50-60% of all miscarriages are the result of chromosomal abnormalities that occur by chance as pre-embryonic cells divide and grow. 

Why do chromosomal abnormalities occur?

In order to be viable and healthy, an embryo requires a specific number of chromosomes. Unfortunately, the physiological process that gives them their chromosomes is complex and prone to error — abnormalities can occur at any point between ovulation and fertilization. 

Prior to ovulation, an egg contains two extra sets of chromosomes. When it’s released from your ovary, one of these extra sets is pushed out of the egg into a tiny cell known as the first polar body. The egg’s second extra set of chromosomes is pushed out during fertilization, when it’s replaced by the chromosomes contained in the fertilizing sperm.  

Once the egg and sperm have each contributed one set of 23 chromosomes, fertilization is complete. An embryo that contains a total of 46 chromosomes (23 matching pairs) is considered normal. 

If, during this complicated process, the embryo loses one or more chromosomes (or gains one or more extra ones), it becomes abnormal. Most abnormal embryos fail to implant in the uterine wall and produce a viable pregnancy, and the vast majority of those that do manage to implant are lost early on in a spontaneous miscarriage. 

If an abnormal embryo continues to develop against all odds, the resulting baby will be born with some type of birth defect. Down’s syndrome is probably the most widely recognized chromosomal disorder that doesn’t always result in miscarriage; it occurs when an embryo receives an extra copy of chromosome 21. 

How does PGD reduce miscarriage risk? 

Although there’s currently no way to prevent chromosomal abnormalities during conception, PGD provides a way to screen embryos for such problems before they’re placed in the womb via in-vitro fertilization (IVF). 

During the IVF process, after your eggs are surgically removed and carefully fertilized with your partner’s sperm or donor sperm, they’re left to develop for a few days in a sterile lab environment. Once the pre-embryo has divided into at least eight cells, it’s possible to remove one of those cells without harming the embryo. 

By taking a tiny, harmless sample (biopsy) of each developing embryo and analyzing the number of chromosomes it contains, we can successfully identify and separate normal from abnormal embryos. 

We can also use PGD to screen chromosomal translocation, another common cause of miscarriage in which an embryo has a normal number of chromosomes (46), but one or more of its 23 pairs isn’t joined together or matched up properly.  

Although PGD can’t currently detect every chromosomal problem in a developing embryo, it can uncover the abnormalities that most commonly result in miscarriage. 

Transferring only viable embryos with normal chromosomes to your uterus can vastly decrease your risk of miscarriage. Research shows that couples who combine IVF with PGD have a 50% reduced risk of miscarriage compared to couples who skip PGD. Even better, PGD can help couples with a history of chromosomal translocation reduce their risk of miscarriage by over 90%. 

If your recurrent miscarriages are keeping you from achieving your family dreams, we can help. To find out if you’re a good candidate for IVF with PGD, call your nearest office in Glendale or Santa Monica, California, or use the easy online tool to schedule a visit with Dr. Sepilian any time.  

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