Low-impact Exercise During Pregnancy???A Study of Safety

Abstract

Several large-scale cohort studies suggest that obese mothers are at increased risk of having infants with neural tube defects and, possibly, other central nervous system (CNS) birth defects. Because obesity and diabetes share similar metabolic abnormalities, a study was planned to determine whether gestational diabetes influences the association between maternal obesity and CNS birth defects. In this population-based case-control study, covering the years 1997 to mid-2000, structured telephone interviews were conducted with mothers of offspring having anencephaly (n ϭ 120), spina bifida (n ϭ 184), holoprosencephaly (n ϭ 49), or isolated hydrocephaly (n ϭ 124). Control women whose infants were neurologically normal were randomly chosen from the same hospitals. Approximately 60% of both cases and control subjects responded. Maternal obesity was defined as a body mass index of 30 kg/m 2 or higher.Pregestational diabetes, both type 1 and type 2, correlated closely with holoprosencephaly (adjusted odds ratio [OR], 47; 95% confidence interval [CI],, and isolated hydrocephaly (OR, 12; 95% CI, 2.9-47). There was no increase in the risk of anencephaly or spina bifida.Gestational diabetes increased only the risk of holoprosencephaly (OR, 2.9; 95% CI, 1.0-8.4). Mothers of infants with anencephaly were less likely than control mothers to have gestational diabetes. Obese mothers were likelier than control subjects to have infants with any of the 4 CNS birth defects. Underweight women were less likely to have an infant with spina bifida. The association between maternal obesity and an increased risk of neural tube defects and isolated hydrocephaly held for all ethnic groups. Associations between maternal obesity and anencephaly (OR, 2.3; 95% CI, 1.2-4.3), spina bifida (OR, 2.8; 95% CI, 1.7-4.5), and isolated hydrocephaly (OR, 2.7; 95% CI, 1.5-5.0) persisted after adjusting for maternal age, ethnicity, education, smoking, alcohol use, and periconceptional vitamin use. For both spina bifida and holoprosencephaly, the joint effects of maternal obesity and gestational diabetes appeared to be interactive.These findings suggest that gestational diabetes and maternal obesity may increase the risk of CNS birth defects through common mechanisms, and they strongly support the need for ways of preventing these conditions. EDITORIAL COMMENT(The epidemic of obesity is worldwide. The prevalence of a body mass index (BMI) Ն30 kg/m 2 in women 18 years of age and older increased from 12% to 18% from 1991 to 1998 (Mokdad AH, et al. JAMA 1999282:1519). The relationship between obesity and diabetes is well known. Does the combination increase the risk of congenital malformations? To investigate the risk of neural tube defect (NTD)-affected pregnancies among obese women (BMI Ն29 kg/m 2 ) compared with women of average prepregnancy weight, Shaw performed a population-based case-controlled study of all hospitals in 55 of 58 counties in California. Compared OBSTETRICSVolume 60, Number 6 OBSTETRICAL AND GYNECOLOGICAL SURVEY ABSTRACTThe major concern...

Acute responses to structured aerobic and resistance exercise in women with gestational diabetes mellitus

“…1 This is despite it being shown in previous trials that moderate-intensity exercise did not cause dangerous levels of overheating. [10][11][12][13] Data on maternal and fetal hemodynamic responses regarding maternal heart rate (HR), fetal heart rate (FHR), and maternal systolic and diastolic blood pressure is also scarce, and conflicting, and almost non-existent for women affected by GDM. Previous research has shown that maternal blood pressure levels slightly increased during aerobic and resistance exercise, but remained within safe limits.…”

Leisure time physical exercise during pregnancy and the risk of miscarriage: a study within the Danish National Birth Cohort

“…Several animal experiments have given support to these hypotheses, 6,7,9,14 while human studies are less conclusive. 8,[10][11][12]15,16 Only few studies have specifically addressed the association between exercise during pregnancy and miscarriage. In the existing body of literature, exercise during pregnancy has generally not been associated with miscarriage, [17][18][19] and one case-control study has even reported a protective effect of exercise during pregnancy.…”

Oxygen saturation response to exercise in healthy pregnant women: a simple protocol and normal range

“…6 A study of 40 healthy women at a mean gestation of 25 weeks found that prolonged low-impact aerobic exercise at a level of 70% maximum predicted heart rate caused a small fall in oxygen saturation but this did not fall below 95%. 7 However, these small studies do not provide a normal range for the oxygen saturation response to moderate exertion after 24 weeks' gestation. Our study demonstrates that oxygen saturation in healthy women during the second and third trimesters of pregnancy is normally greater than or equal to 95% at sea level, in keeping with the normal value in men.…”