Obesity and Miscarriage - The Link Between Body Weight and Pregnancy Loss
Updated June 18, 2014.
Summary of Evidence
The evidence is fairly clear that obesity is statistically associated with increased risk of pregnancy complications, ranging from miscarriage to problems later in pregnancy. Obesity also seems to increase the risk of recurrent miscarriages. Multiple studies have documented the link between obesity and the risk of miscarriage, and a few have even shown that losing weight seems to reduce the risk of miscarriage for patients who are overweight and have a history of miscarriage.
Doctors suspect that obesity is also responsible for the increased miscarriage rates in women with polycystic ovarian syndrome (PCOS). Women with this disorder are more likely to be overweight, and women with PCOS, who are able to lose weight, also seem to reduce their own risk of miscarriage. The ACOG, the professional U.S. organization for OB/GYNs, does recommend that doctors offer nutritional counseling for women with obesity who are planning a pregnancy.
A Perspective on the Evidence
Even though the link between obesity and miscarriage seems to be real, it's important to remember that things simply aren't that simple. Obviously, the majority of women who are overweight do not have miscarriages, so there must be other factors in play for those that do have miscarriages. In addition, with obese women who miscarry, they usually have successful subsequent pregnancies, despite the increased risk of recurrent miscarriages. Unfortunately, doctors do not yet have all the answers in this area of research.
The link between miscarriages and obesity should also never be oversimplified to say that miscarriages are the woman's fault for eating too much and not exercising. Very few people are obese by choice, and a person's weight often involves a complex interworking of physiological and psychological factors that have to be overcome in order to lose weight. Some researchers even suspect genetic involvement in obesity.
It is possible that the complex factors that cause some women to be overweight also cause the miscarriages for affected women. It is also possible that losing weight reduces the impact of those pre-existing factors on the subsequent pregnancy. Right now we simply do not know.
Where It Stands
It does seem that losing weight can reduce one's risk of miscarriage, whether that's due to losing the weight itself or some other reason. If you wish to lose weight, try to do so safely under a doctor or nutritionist's guidance -- and with a healthier lifestyle as the goal rather than a specific number of pounds or clothing size as the target.
It is not fair that some of us have to struggle harder than others to have a healthy body weight. And again, rarely is the process so simple as choosing to eat less and exercise more. Consider finding a support group, such as Weight Watchers, to help you throughout the process. (You can also visit About.com's Weight Loss forums and Calorie Count to help get on your way.)
Finally, if you are overweight and have suffered a miscarriage, resist the temptation to assume your weight was the cause and blame yourself for the miscarriage(s) you may have had. No one can say with certainty what has caused a past miscarriage unless laboratory studies indicated a clear cause, and obesity is not something that can be proven as a cause of any specific miscarriage. Remember that whether you lose weight or not, your odds of having a successful next pregnancy are higher than your odds of having another miscarriage.
In addition, if you are currently pregnant and feel you are overweight, talk to your doctor with any concerns about your diet and exercise, although pregnancy is generally not the best time to implement a weight-loss plan.
Sources:
American College of Obstetricians and Gynecologists, "ACOG Issues Guidance to Ob-Gyns on Impact of Obesity During Pregnancy." 31 Aug 2005. Accessed 13 May 2008.
Clark, A.M., B. Thornley, L. Tomlinson, C. Galletley, and R.J. Norman, " Weight loss in obese infertile women results in improvement in reproductive outcome for all forms of fertility treatment." Human Reproduction 1998. Accessed 13 May 2008.
Lashen, H., K. Fear, and D.W. Sturdee, "Obesity is associated with increased risk of first trimester and recurrent miscarriage: matched case–control study." Human Reproduction May 2004. Accessed 13 May 2008.
Summary of Evidence
The evidence is fairly clear that obesity is statistically associated with increased risk of pregnancy complications, ranging from miscarriage to problems later in pregnancy. Obesity also seems to increase the risk of recurrent miscarriages. Multiple studies have documented the link between obesity and the risk of miscarriage, and a few have even shown that losing weight seems to reduce the risk of miscarriage for patients who are overweight and have a history of miscarriage.
Doctors suspect that obesity is also responsible for the increased miscarriage rates in women with polycystic ovarian syndrome (PCOS). Women with this disorder are more likely to be overweight, and women with PCOS, who are able to lose weight, also seem to reduce their own risk of miscarriage. The ACOG, the professional U.S. organization for OB/GYNs, does recommend that doctors offer nutritional counseling for women with obesity who are planning a pregnancy.
A Perspective on the Evidence
Even though the link between obesity and miscarriage seems to be real, it's important to remember that things simply aren't that simple. Obviously, the majority of women who are overweight do not have miscarriages, so there must be other factors in play for those that do have miscarriages. In addition, with obese women who miscarry, they usually have successful subsequent pregnancies, despite the increased risk of recurrent miscarriages. Unfortunately, doctors do not yet have all the answers in this area of research.
The link between miscarriages and obesity should also never be oversimplified to say that miscarriages are the woman's fault for eating too much and not exercising. Very few people are obese by choice, and a person's weight often involves a complex interworking of physiological and psychological factors that have to be overcome in order to lose weight. Some researchers even suspect genetic involvement in obesity.
It is possible that the complex factors that cause some women to be overweight also cause the miscarriages for affected women. It is also possible that losing weight reduces the impact of those pre-existing factors on the subsequent pregnancy. Right now we simply do not know.
Where It Stands
It does seem that losing weight can reduce one's risk of miscarriage, whether that's due to losing the weight itself or some other reason. If you wish to lose weight, try to do so safely under a doctor or nutritionist's guidance -- and with a healthier lifestyle as the goal rather than a specific number of pounds or clothing size as the target.
It is not fair that some of us have to struggle harder than others to have a healthy body weight. And again, rarely is the process so simple as choosing to eat less and exercise more. Consider finding a support group, such as Weight Watchers, to help you throughout the process. (You can also visit About.com's Weight Loss forums and Calorie Count to help get on your way.)
Finally, if you are overweight and have suffered a miscarriage, resist the temptation to assume your weight was the cause and blame yourself for the miscarriage(s) you may have had. No one can say with certainty what has caused a past miscarriage unless laboratory studies indicated a clear cause, and obesity is not something that can be proven as a cause of any specific miscarriage. Remember that whether you lose weight or not, your odds of having a successful next pregnancy are higher than your odds of having another miscarriage.
In addition, if you are currently pregnant and feel you are overweight, talk to your doctor with any concerns about your diet and exercise, although pregnancy is generally not the best time to implement a weight-loss plan.
Sources:
American College of Obstetricians and Gynecologists, "ACOG Issues Guidance to Ob-Gyns on Impact of Obesity During Pregnancy." 31 Aug 2005. Accessed 13 May 2008.
Clark, A.M., B. Thornley, L. Tomlinson, C. Galletley, and R.J. Norman, " Weight loss in obese infertile women results in improvement in reproductive outcome for all forms of fertility treatment." Human Reproduction 1998. Accessed 13 May 2008.
Lashen, H., K. Fear, and D.W. Sturdee, "Obesity is associated with increased risk of first trimester and recurrent miscarriage: matched case–control study." Human Reproduction May 2004. Accessed 13 May 2008.