UNDERSTANDING RECURRENT PREGNANCY LOSS – Part 1: CAUSES

Having a pregnancy loss can be heartbreaking. Having multiple miscarriages can be truly devastating. Each new pregnancy brings hope, but also great anxiety; each new miscarriage aggravates the feelings of loss, grief and sense of failure… 

It is natural to want answers. Knowing the reason of a pregnancy loss can help you make sense of what has happened. Furthermore, finding the cause of the problem will help prevent it from happening again, or at least reduce its risk. Things are not so simple though when it comes to recurrent miscarriage: most of the times, investigations don’t come out with a clear answer…

The purpose of this article is to help you understand recurrent pregnancy loss and to present the most recent scientific information regarding its cause, diagnosis and treatment. Due to the extensiveness of the subject, this first article will deal only with the known causes of repeated miscarriage; two other articles on testing and treatment will follow.

What is Recurrent Pregnancy Loss?

A pregnancy loss is the spontaneous loss of a pregnancy before 24 weeks of gestation. Recurrent Pregnancy Loss (RPL) is considered after the loss of two or more pregnancies; this includes pregnancies after spontaneous conception or after assisted reproduction (e.g. IUI and IVF/ICSI). Other pregnancy complications such as ectopic pregnancies and molar pregnancies are not included. 

  • Primary RPL is a term used for women who have not had a baby before their pregnancy losses. 
  • Secondary RPL means they have had at least one baby before their losses. 

It is estimated that RPL affects 1 to 2% of couples.

What causes RPL?

There are several factors that may be responsible for RPL. But you should know that in about half (50%) of the RPL cases, no cause is found. This is called unexplained RPL.

Here are some of the causes that are related to multiple miscarriages:

1) Age

The older you are, the greater your risk of having a miscarriage. If a woman is aged over 40, more than 50% of pregnancies end in a miscarriage. The same is true for RPL. Miscarriages may also be more common if the father is older, although it is not clear whether paternal age is related to repeated miscarriages.

2) Genetic problems

  • Genetic defects resulting in an abnormal fetus can be a major cause of miscarriage. About half of all miscarriages in the first three months of pregnancy are due to chromosomal problems, although most of the times this is of random occurrence .
  • In about 4 in 100 couples (4%) with recurrent miscarriage, one partner will have an abnormality on one of their chromosomes. Although this may not affect the parent, it may sometimes cause a miscarriage.

3) Thrombophilia

Thrombophilia is a condition in which your blood clots more than usual; it may be inherited (passed down genetically) or acquired (not inherited). Thrombophilia is not only related to RPL, but also to other pregnancy complications.

  • Inherited thrombophilia is due to certain gene defects. According to the gene involved, it may be related to early or late repeated miscarriage.
  • Antiphospholipid syndrome (APS) is an acquired thrombophilic condition. It is uncommon but strongly related to RPL.

4) Abnormal hormone levels

Miscarriage can occur when the uterine lining does not develop sufficiently, therefore the fertilized egg does not have the best environment for implantation and nourishment; this can be the result of abnormal hormone levels.

Women with thyroid problems and women with diabetes (or insulin problems) are usually at a higher risk for miscarriage due to hormonal imbalances. Women with polycystic ovaries syndrome, are also at risk. In addition, elevated prolactin levels can also disrupt normal uterine lining development.

5) Problems of the uterus

The shape of the uterus may cause miscarriage, usually by interfering with the implantation of the fertilized egg.

  • A septum, that is a fibrous wall which divides the uterine cavity, can cause poor implantation and pregnancy loss.
  • Uterine fibroids, polyps, adhesions may eventually cause pregnancy loss by blocking the opening of the fallopian tube(s) or if their position is affecting the normal functioning of the uterine lining. Their relationship though with RPL is less clear.
  • Another probable cause of miscarriage is an incompetent cervix, meaning the cervical muscle is weak and cannot remain closed; as the developing fetus grows puts pressure on the cervix, it starts to shorten and open, resulting in miscarriage.

6) Immune Causes

It has been suggested that some women miscarry because their immune system does not respond to the baby in the usual way. This is known as an alloimmune reaction. Although numerous immunological factor have been investigated, there is no clear evidence to support this theory at present, and further research is needed.

7) Sperm defects

Sperm DNA is the most important part of the sperm, as it contains the genetic information that will be passed on to the baby. DNA can be damaged during sperm production and transport; this damage is known as DNA fragmentation. The recents years it has become evident that high levels of sperm DNA fragmentation seem to increase the likelihood of pregnancy loss.

Sperm DNA fragmentation can be provoked by stress, smoking, recreational drugs, obesity and other unhealthy lifestyle factors. 

8) Infections

Certain infections have been proposed as the cause of RPL, such as rubella, herpes simplex, ureaplasma, cytomegalovirus and chlamydia. However, the role of these infections in recurrent miscarriage is unclear and probably null. A persistent infection of the endometrium (chronic endometritis) may be related to RPL, but more research is needed to know this for sure.

9) Environmental Factors

Certain toxins you may be exposed to can also result in fetal damage or miscarriage, especially if you experience regular exposure. Toxins such as organochlorine pesticides, certain heavy metals (selenium, lead cadmium), organic solvents, anesthetic gases (occupational exposure), have all been blamed for causing RPL. Likewise, lack of certain micronutrients (zinc, copper, vitamin E) have been proposed as possible causes of RPL. 

Although exposure to possible hazardous substances should be avoided during pregnancy (this is true for all pregnant women), there are insufficient data to recommend protection against a certain occupational or environmental factor in women with RPL.

10) Lifestyle-related factors 

  • Studies also indicate that the use of marijuana, tobacco, alcohol and excessive consumption of caffeine can all affect fetal development and result in miscarriage. Although their relationship with RPL is not clear, it is recommended that women limit or avoid their use during pregnancy.
  • Being overweight or significantly underweight have been both associated with miscarriages, as well as with pregnancy and childbirth complications. While maternal obesity is a strong risk factor in RPL, the association with very low weight is less clear. Male overweight may also be a negative factor, since is responsible for DNA damage (see above). Striving for a healthy, normal weight is recommended, both for the female and male partner. 
  • Intensive exercise or no exercise at all have been both blamed as a cause of RPL, but there is not clear scientific evidence and further research is needed. Moderate (leisure) physical activity seems to be safe, and beneficial for other pregnancy complications, such as diabetes and hypertension of pregnancy.
  • Whether stress increases the chances of another pregnancy loss in the next pregnancy is a major concern for all couples with RPL. Studies to date indicate that there is an association between stress and pregnancy loss, but it is not whether the stress is a result or a causal factor in RPL.

 

Read the second part here: Understanding Recurrent Pregnancy Loss – Testing (coming soon)

 

Photo credits

futurelab-ksa.com

 

PHTHALATES LINKED TO PREGNANCY LOSS -AND OTHER HEALTH PROBLEMS

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A recent study came -again- to incriminate certain environmental toxins known as phthalates as being responsible for pregnancy losses. Women undergoing assisted reproduction techniques (in-vitro fertilization or intra-uterine insemination) had urine exams to assess the presence of certain phthalates; it became evident that women with high levels of phthalates had up to three times increased risk of pregnancy loss. The study was recently presented at the Annual Meeting of American Society for Reproductive Medicine (ASRM).

For several years now we have been hearing about the toxic effects of phthalates, but what are they exactly? Where do we find them? Are they really harmful? Check out this article to learn more about these enigmatic toxins…

What are Phthalates?

Phthalates are chemicals used to soften plastics and make them more flexible (they are also known as plasticizers). These substances do not bound to plastics, therefore they are continuously released into the air, foods or liquids. Certain phthalates are used as dissolving agents for other materials.

Where do we find them?

Phthalates are used in an astounding array of products. They are most commonly found in:

  • Plastic bottles.Phthalates plastic bottles
  • Plastic containers and plastic wraps.
  • Cosmetics: in creams and lotions (to help them penetrate and soften the skin), in perfumes (to help them last longer), in hair sprays (to reduce stiffness), in nail polish (to prevent chipping), in deodorants, soaps, shampoos and almost every cosmetic with fragrance, including baby products.
  • Household products: air fresheners, paints, plastic flooring.
  • Plastic toys and other baby products such as teethers.
  • Certain medical devices, e.g., blood bags, intubation tubes, intravenous catheters.
  • Objects made of vinyl or PVC.
  • Phthalates are present even in seemingly unexpected sources. One example is milk: even in glass bottles, high levels of phthalates have been found, presumedly due to the plastic tubing used in milking machines.

We get exposed to phthalates by:

  • Ingestion: eating food contaminated from food packaging; drinking beverages from plastic bottles that leach the chemical; sucking plastic objects (e.g., baby toys, teethers).
  • Absortion: using cosmetics products. According to the CDC, women of childbearing age have the highest levels of phthalates, possibly due to the use of cosmetics.
  • Inhalation: breathing dust or fumes from products containing vinyl (vinyl floors, the interior of cars, shower curtains, etc).

Which are the most commonly used phthalates?

Phthalates perfumeThese chemicals have very difficult names, but there are a few you may want to keep in mind (see the studies below):

-In cosmetics: the primary phthalates used in cosmetic products have been dibutylphthalate (DBP), used in nail polishes; dimethylphthalate (DMP), used in hair sprays; and diethylphthalate (DEP), used as a solvent and fixative in fragrances. According to latest survey of cosmetics conducted by the Food and Drug Administration (FDA) in 2010, DBP and DMP are being used rarely, while DEP is the most commonly used phthalate. The use of DBP and DEHP is banned in the European Union  but they are still found in cosmetic products.

-In food packaging: the most commonly used is Di-(2-ethylhexyl) phthalate (DEHP). Bisphenol-A (BPA) is not a phthalate, but is also being used as plasticizer in food packaging and plastic bottles.

-In paints, plastic and PVC objects, solvents and adhesives: DEHP, Diisobutyl phthalate (DIBP) and DBP (also called DnBP).

-In children toys and child care products: In the USA, phthalates used in these products have been divided in three categories:Phthalates toy ducks

  1. permanent ban (permanently prohibits the sale of any “children’s toy or child care article” individually containing concentrations of more than 0.1% of DBP, BBP or DEHP);
  2. interim ban (prohibits on an interim basis the sale of “any children’s toy that can be placed in a child’s mouth” or “child care article” containing concentrations of more than 0.1% of DNOP, DINP, or DIDP); and
  3. currently unrestricted under Section 108 of the Consumer Product Safety Improvement Act of 2008 (DMP, DEP, DIBP, DCHP, DIHEPP, DIOP, DPHP).

Similar recommendations apply in Europe, where the six above-mentioned products are banned.

What is the evidence linking phthalates to pregnancy losses?

In addition to the recent American study (where they measured metabolites of DEHP), two previous studies had found a relationship between phthalates and miscarriages:

In 2012, a Danish study  found an increased risk of early pregnancy loss in women with high urine levels of DEHP‘s breakdown products. More recently, a Chinese study, comparing urine samples of women who had miscarriages and healthy women found that pregnancy loss was associated with higher levels or three phthalates: DEP, DBP, and di-isobutyl phthalate (DiBP).

Another American study also found and increased risk of miscarriages in women with high levels of BPA.

Eliminating phthalates and BPA from our lives is virtually impossible, but you can take some measures to minimize exposure, especially if you are trying to conceive, are pregnant or have young children”

Are there any other health risks?

Phthalates are widely known as endocrine disruptors: they mimic hormones, interfering with their function. Some possible consequences of this are:

Effect on male fertility: phthalate exposure in men was associated with reduced fecundity.

Birth defects in baby boys: several studies have found abnormalities in baby boys’ genitals when pregnant women were exposed to high levels of certain phthalates; another study found increased risk of hypospadias (the opening of the urethra is on the underside of the penis) in occupational exposure of pregnant women.

Neurological problems in newborns, infants and children: such as attention deficit hyperactivity disorder (ADHD), reduced IQ, behaviour problems.

Obesity: both in children and adults.

Asthma: in children when pregnant women were exposed to high level of phthalates.

Interference with puberty in girls: the evidence is inconsistent on this subject; while some studies found that phthalates may be related with precocious puberty, others reported delayed puberty.

Breast cancer: a small study showed increased breast cancer risk, but the evidence is not conclusive; there is a large study being conducted in the USA, which will provide more clear answers on this matter.

What can I do to reduce exposure to phthalates?

Phthalates glass food containersEliminating phthalates and BPA from our lives is virtually impossible -they seem to be everywhere- but you can take some measures to minimize exposure, especially if you are trying to conceive, are pregnant or have young children:

  1. Read labels on personal care products. Unfortunately, manufacturers are not forced to list phthalates, and  they can be added as a part of the “fragrance.” Many companies have voluntarily removed phthalates from their products, so you may search for products labelled as “phthalate-free”.
  2. Limit the use of baby care products in babies and young children.
  3. Don’t microwave food in plastic, or use only “microwave safe” and phthalate-free containers to microwave food or drinks. Phthalates can leach from containers (or plastic wrap) into foods on contact and when heated, particularly oily foods or with a high fat content. Don’t put plastic containers in the dishwasher (heat will increase phthalates leaching).
  4. Replace plastic bottles, cups, dishes and food containers with those made of glass, porcelain or stainless steel, especially for hot food and beverages.
  5. Check labels on plastic bottles and containers: choose only those with recycle codes 1, 2, 4, or 5. Plastics made of polyethylene terephthalate (PET) or high-density polyethylene (HDPE) are safer than those made of PVC (“PET” or “HDPE” may be printed on the label or the bottom of the bottle).
  6. Use only toys and toothbrushes labeled “phthalate- free”. There are strict regulations banning the most dangerous phthalates in toys and baby products, both in the USA and in Europe.
  7. Reduce your use of canned foods, as they are often lined with material that contains BPA. Prefer fresh products or those in glass containers. Avoid canned milk (including canned formula for babies).
  8. Phthalates baby bottlesChoose only bottles and cups that are BPA-free. In fact, BPA was banned in all baby products in 2011 in Europe, and since 2012 in the USA.
  9. When using paints or solvents, keeps the area well ventilated. Prefer natural paints, phthalate-free (DBP is the phthalate usually used in these products).
  10. Choose non-vinyl products, such as shower curtains, raincoats or furniture, as the chemical off-gassing from these products introduces phthalates to your environment.
  11. Keep your house clean, as phthalates can remain in dust.
  12. Avoid air fresheners; prefer essential oils instead.

Is anything being done?

Phthalates safe cosmeticsAs people are becoming more aware of the harmful effects of phthalates, increasing information is being available to consumers; websites such as the Campaign for Safe Cosmetics have actively advocated the elimination of dangerous chemicals from cosmetics and personal care products. As a result, certain companies and retailers have been taking measures to reduce toxic substances in their products.

Initiatives are also being taken at governmental level. European authorities have restricted the use of phthalates in some baby products, cosmetics, and plastics designed to come into contact with food; more phthalates will be soon banned from medical equipment, electrical and electronic devices. Recently, a very extensive Report to the U.S. Consumer Product Safety Commission by the Chronic Hazard Advisory Panel on Phthalates and Phthalates alternatives (CHAP) analyzed the available data on each phthalate and phthalates alternative and provided recommendations, which will hopefully lead to banning certain phthalates that proved to be toxic.

 

Photo credits

Getty Images; Reciclado creativo, Flickr.com; Etienne, Flickr.com; Pixabay.com; Target.com; Alicia Voorhies, Flickr.comjillsamter.com