Pregnant women who were underweight faced a 70 percent higher risk of having a miscarriage.
In women between gestation weeks 4 and 12 in whom no apparent signs of a threatened miscarriage could be diagnosed, risk of miscarriage was significantly increased in women with lower body mass index (< or =20 kg/ m(2)) prior to the onset of the miscarriage. This risk factor was even more pronounced in the subcohort of women recruited between gestation weeks 4 and 7.
http://www.ncbi.nlm.nih.gov/pubmed/18616898
The effect of BMI on the risk of miscarriage was significant after adjusting for several independent risk factors. Compared with the reference group (BMI 18.5 to 24.9 kg/m2), underweight women had a similar risk of miscarriage, whereas there was progressive increase of risk in overweight, obese, and very obese groups. Odds ratios are as follows: BMI < 18.5: OR = .94; BMI 18.5 to 24.9: OR = 1; BMI 25 to 29.9: OR = 1.29; BMI 30 to 34.9: OR = 1.71; BMI >35: OR = 2.19.
http://www.ncbi.nlm.nih.gov/pubmed/12055331
Sixteen studies were included in the meta-analysis. Patients with a body mass index of > or =25 kg/m(2) had significantly higher odds of miscarriage, regardless of the method of conception (odds ratio, 1.67). Subgroup analysis from a limited number of studies suggested that this group of women may also have significantly higher odds of miscarriage after oocyte donation (odds ratio, 1.52) and ovulation induction (odds ratio, 5.11).
http://www.ncbi.nlm.nih.gov/pubmed/18068166
This study analyzed 436 patients undergoing intracytoplasmic sperm injection cycles. Patients answered a questionnaire and regression analysis examined the relationship between lifestyle and BMI with the intracytoplasmic sperm injection cycles outcomes. RESULTS: No influence of lifestyle and obesity was observed on the number of oocytes recovered. Obesity reduced the normal fertilization rate (coefficient: -16.0) and increased the risk of miscarriage (OR: 14.3).
http://www.ncbi.nlm.nih.gov/pubmed/20597616
Obese (n = 18) and non-obese (n = 26) women with PCOS underwent long protocol pituitary suppression, ovarian stimulation and intracytoplasmic sperm injection with fresh embryo transfer. Miscarriage rate was significantly higher in obese women compared with the non-obese women with PCOS (60% vs 6.7%).
http://www.ncbi.nlm.nih.gov/pubmed/21417650
We found a significant increase in normal embryonic karyotypes in the miscarriages of overweight and obese women (BMI > or = 25). These results suggest that the excess risk of miscarriages in the overweight and obese population is independent of embryonic aneuploidy.
http://humrep.oxfordjournals.org/content/early/2010/02/26/humrep.deq025.full
The endocrinological changes in obesity that may cause these adverse effects are complex and include changes in circulating adipokines and sex steroids as well as insulin resistance. Considerable evidence suggests an adverse effect of obesity on the risk of miscarriage and other maternal and fetal complications. Obese patients are also more prone to infertility. The most important single method to improve reproductive performance in obese women is weight loss that can be achieved with lifestyle changes and diet.
http://www.ncbi.nlm.nih.gov/pubmed/18443342
Obesity can affect reproduction through fat cell metabolism, steroids and secretion of proteins such as leptin and adiponectin and through changes induced at the level of important homeostatic factors such as pancreatic secretion of insulin, testosterone synthesis by the ovary and sex hormone-binding globulin (SHBG) production by the liver. WHO estimates that 9 to 25% of women in developed countries are severely obese, and obese mothers are much more likely to have obese children, especially if they have gestational diabetes. Obesity-associated anovulation may lead to infertility and to a higher risk of miscarriage. Management of anovulation with obesity involves diet and exercise as well as standard approaches to ovulation induction. Many obese women conceive without assistance, but pregnancies in obese women have increased rates of pregnancy associated hypertension, gestational diabetes, large babies, Cesarean section and perinatal mortality and morbidity.
http://humupd.oxfordjournals.org/cgi/content/abstract/dmk003v1
Obese women trying to become pregnant experience longer times to conception, even if they are young and have a regular menstrual cycle. Obese women have alterations in their ovaries which might be responsible for an egg's inability to make an embryo, according to a new study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM). Obese women have abnormally high levels of fats and inflammation in the fluid surrounding their eggs which can impact an egg's developmental potential. In addition, inflammation can damage cells and when this happens to eggs it can affect embryo survival.
http://www.sciencedaily.com/releases/2009/03/090303082817.htm
In a conditional logistic regression analysis including age, gestational age, serum creatinine, methylmalonic acid, cystathionine, body mass index (BMI), cigarette smoking, alcohol ingestion and use of multivitamins the risk of miscarriage was significantly associated with methylmalonic acid (indicates vitamin B12 deficiency)(odds ratio =3.80 per quartile increase in methylmalonic acid), BMI (odds ratio =5.49 per quartile) and gestational age (odds ratio =0.10 per increase of interval in gestational age). CONCLUSIONS: Increased serum methylmalonic acid and BMI concentrations are associated with miscarriage in Brazilian women.
http://www.ncbi.nlm.nih.gov/pubmed/20036223
Maternal obesity was associated with a more than doubled risk of stillbirth (odds ratio = 2.8) and neonatal death (odds ratio = 2.6) compared with women of normal weight. No statistically significantly increased risk of stillbirth or neonatal death was found among underweight or overweight women.
http://www.ncbi.nlm.nih.gov/pubmed/15777435
Statistical comparison was made between infertility patients with and without insulin resistance. Logistical regression analysis was used to assess the effect of insulin resistance and several other factors simultaneously on the risk of miscarriage. The association of insulin resistance with the risk of miscarriage was significant after adjusting for other risk factors. The effect of overweight/obesity and polycystic ovarian syndrome was not statistically significant in the multivariate model. Because of the high prevalence of insulin resistance in obese patients, the risk of miscarriage in these patients can be raised.
http://www.ncbi.nlm.nih.gov/pubmed/17244790
A total of 42 consecutive women with recurrent miscarriage (three or more consecutive miscarriages, mean: 3.9) with no parental chromosome rearrangement or uterine abnormality were studied during the early follicular phase under standardized conditions. Controls were 42 nulligravid females with tubal or male factor infertility without miscarriage. Obesity [BMI > or = 25] was more prevalent (23 (54%) versus 5 (12%) women) in the study than the control group. Reduction of body weight and may reduce the rate of miscarriage in a subsequent pregnancy in these women.
http://www.ncbi.nlm.nih.gov/pubmed/10374087
Among intrauterine environmental factors, nutrition appears to play the most critical role in influencing placental and fetal growth. Changes in maternal nutritional status during pregnancy often results in permanent structural and functional deficits in fetal, as well as, postnatal growth of animals. Maternal undernutrition or overnutrition during pregnancy can impair fetal growth.
http://www.ncbi.nlm.nih.gov/pubmed/20434853