Do Multivitamins Reduce the Risk of Miscarriage?

Written by Dr. Steve Chaney on . Posted in Multivitamins and Miscarriage, Vitamins and Health, Weight Loss

Will A Multivitamin A Day Keep YourBaby Healthy?

Author: Dr. Stephen Chaney

multivitamins reduce risk of miscarriageThe standard medical advice for years has been to take a prenatal supplement (basically a multivitamin with extra folic acid, iron and sometimes calcium) both before and during pregnancy. Does that really make a difference? Will it reduce the risk of miscarriage? Will it give you a healthier baby?  A recent study suggests that multivitamin use may significantly decrease your risk of miscarrying, but before going into the study you need a little background.

 

It’s a new world. It used to be that a woman didn’t know for sure that she was pregnant until she had missed one or two periods and finally got an appointment with her doctor – a month or two after conception actually occurred. In today’s world accuracy in home pregnancy tests allow women to learn they are pregnant much earlier – often before the first missed period.

With the early detection of pregnancy has come the realization that miscarriage rates are much higher than previously assumed. In spite of improved prenatal care, the rate of miscarriages in the US increased by 1% per year between 1985 and 2005. In part that is because women using the in-home pregnancy tests are detecting their pregnancies much early. However, it also reflects the fact that early miscarriages are often asymptomatic. They can only be detected by negative pregnancy tests.

With that in mind, let’s look at the study.

Do Multivitamins Reduce the Risk of Miscarriage?

pregnancy and miscarriageThis study (Louis et al, Fertility and Sterility, doi.org.10.1016/j.fertnstert.2016.03.009, 2016), had a very interesting design. It enrolled 501 couples ages 18-40 from Michigan and Texas who were actively trying to become pregnant into something called the Longitudinal Investigation of Fertility and the Environment (LIFE) Study. The women in the study were instructed in the use of a commercial fertility urine test to help the couples plan their intercourse to maximize the chances of conceiving. They were also instructed in the use of a commercial pregnancy urine test to determine the onset and potential loss of pregnancy (miscarriage).

The couples were given no guidance on health practices to follow before and during pregnancy. They were interviewed individually upon enrolment to obtain sociodemographic, lifestyle, and medical history information. They were asked to keep a daily journal recording things like cigarettes use, consumption of alcoholic or caffeinated beverages, and multivitamin use (The journal did not distinguish between over-the-counter multivitamins and prescribed prenatal vitamins).

Of the couples who enrolled in the study, 347 (69%) of them became pregnant. Three of the women conceived twins and were eliminated from the study. Of the remaining 344 women, 98 (28%) of them experienced a miscarriage during the first 22 weeks. No miscarriages were observed after 22 weeks.

When they looked at risk factors that affected pregnancy loss (miscarriages):

  • The miscarriage rate was almost double for women over 35, which is consistent with previous studies.
  • Consumption of two or more caffeinated beverages/day by either partner prior to conception and during early pregnancy significantly increased the risk of miscarriage
  • Daily multivitamin use by the woman prior to conception reduced the risk of miscarriage by 55%. If the vitamin use was continued through the first 7 weeks of pregnancy, the risk of miscarriage was reduced by 79%.
  • No effect of obesity, cigarette smoking, and alcohol use on miscarriage risk was seen in this study, which is different from most previous studies.

Putting This Study Into Perspective

This was a fairly well designed study, but it is a single study.  Let’s put each of the main findings in the context of previous studies.

Multivitamin Use: Earlier studies have shown that supplements containing extra folic acid probably reduce miscarriages. However, now that foods are routinely fortified with folic acid in the US, the benefit of multivitamins and prenatal supplements has become more controversial. Some studies have shown, like this one, that multivitamins reduce miscarriage risk. Others did not. However, multivitamin use before and during pregnancy has relatively few risks, so it is still probably a good idea.

Caffeinated Beverages: There have been relatively few studies to date on the effect of caffeinated beverages on miscarriage risk, but the few that have been performed tend to agree that caffeinated beverages may increase the risk of miscarriage. While the data are far from definitive at this point, it is probably a good idea to limit your caffeinated beverages before and during pregnancy.

Age: Age is a well-established risk factor for miscarriages. While many consider 40 as the threshold for increased risk, this study and several other recent studies suggest it may be closer to 35. That doesn’t mean that you shouldn’t try to have a baby if you are over 35, but it does mean that you will probably want to avoid any lifestyle factors that might increase your risk of miscarriage.

Other Factors:This study did not find an effect of obesity, smoking or alcohol on pregnancy risk. However, many other studies have shown that each of these increases the risk of miscarriage. It’s probably a good idea to drop a few extra pounds and avoid both smoking and alcohol if you wish to maximize your chances of a successful pregnancy outcome.

If You Are Pregnant, What Does This Study Mean For You? 

preventing miscarriageThis study supports multivitamin use before and during pregnancy and suggests that excessive consumption of caffeinated beverages may have a negative effect on pregnancy outcome. However, it doesn’t significantly alter the standard medical advice for what you should do before and during pregnancy.

  • Daily multivitamin use, both prior to and during pregnancy, is probably a good idea. Not all studies agree, but some studies suggest that it will significantly decrease the risk of miscarriage.
  • Obesity and diabetes increase miscarriage risk. The good news is that even a 5-10% weight loss often is sufficient to reverse diabetes and may improve pregnancy outcome as well.
  • If you are over 35, your risk of suffering a miscarriage is significantly increased.
  • Smoking and alcohol use should be avoided. Both are likely to increase your risk of miscarriage.
  • Recent studies suggest that the consumption of two or more caffeinated beverages a day may also increase your risk of miscarriage, so don’t overindulge in caffeinated beverages. Be aware that it’s not just coffee and tea that are caffeinated. Many sodas are caffeinated as well.

 

The Bottom Line

 A recent study showed:

 

  • Daily multivitamin use by the woman prior to conception reduced the risk of miscarriage by 55%. If the vitamin use was continued through the first 7 weeks of pregnancy, the risk of miscarriage was reduced by 79%.
  • Consumption of two or more caffeinated beverages/day by either partner prior to conception and during early pregnancy significantly increased the risk of miscarriage
  • The miscarriage rate was almost double for women over 35, which is consistent with previous studies.
  • No effect of obesity, cigarette smoking, and alcohol use on miscarriage risk was seen in this study, which is different from most previous studies.
  • This study reinforces the recommendation for multivitamin or prenatal vitamin use, but the standard medical advice for a successful pregnancy isn’t really changed:
  • Daily multivitamin use, both prior to and during pregnancy, is probably a good idea. Not all studies agree, but some studies suggest that it will significantly decrease the risk of miscarriage.
  • Obesity and diabetes increase miscarriage risk. The good news is that even a 5-10% weight loss often is sufficient to reverse diabetes and may improve pregnancy outcome as well.
  • If you are over 35, your risk of suffering a miscarriage is significantly increased. That doesn’t mean that you shouldn’t try to have a baby if you are over 35, but it does mean that you will probably want to avoid any lifestyle factors that might increase your risk of miscarriage.
  • Smoking and alcohol use should be avoided. Both are likely to increase your risk of miscarriage.
  • Recent studies suggest that the consumption of two or more caffeinated beverages a day may also increase your risk of miscarriage, so don’t overindulge in caffeinated beverages. Be aware that it’s not just coffee and tea that are caffeinated. Many sodas are caffeinated as well.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney

 

low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?

 

How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.

 

Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.

 

What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]

 

low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line

 

  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

For more details read the article above.

 

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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