Maternal healthy lifestyle during early pregnancy and offspring birthweight: differences by offspring sex.

PURPOSE: Individual maternal lifestyle factors during pregnancy have been associated with offspring birthweight; however, associations of combined lifestyle factors with birthweight and potential differences by offspring sex have not been examined. MATERIALS AND METHODS: Participants (N = 2924) were identified from a pregnancy cohort in Washington state. Lifestyle factors during early pregnancy were dichotomized based on Alternate Healthy Eating Index score ≥62, leisure time physical activity (LTPA) ≥ 150 min/week, not smoking during pregnancy and Perceived Stress Scale score ≤3, then combined into a lifestyle score (0-4). Regression models were run overall and stratified by offspring sex, prepregnancy overweight/obese (BMI ≥25 kg/m2) and prepregnancy LTPA. RESULTS: Overall, 20% of participants had healthy diet, 95% were nonsmokers, 55% had low stress levels, and 66% were physically active. Lifestyle score was not associated with birthweight (ß = 3.3 g; 95% CI: -14.5, 21.0); however, associations differed by offspring sex (p = .009). For each unit increase in lifestyle score, there was a suggested 22.4 g higher birthweight (95% CI: -2.7, 47.6) among males and 14.6 g lower birthweight (95% CI: -39.9, 10.7) among females. Prepregnancy BMI and LTPA did not modify associations. CONCLUSIONS: Healthy lifestyle score in early pregnancy may be associated with greater birthweight among male offspring, but lower birthweight among female offspring.

Healthy Lifestyle During Early Pregnancy and Risk of Gestational Diabetes Mellitus.

Previous studies have found associations between individual healthy behaviors and reduced risk of gestational diabetes mellitus (GDM); however, the association of composite healthy lifestyle during pregnancy with GDM has not been examined. Participants in the Omega Study (n = 3,005), a pregnancy cohort study conducted in Washington State (1996-2008), reported information on diet, physical activity, smoking, and stress during early pregnancy. Lifestyle components were dichotomized into healthy/unhealthy and then combined into a total lifestyle score (range, 0-4). Regression models were used to determine relative risk of GDM (n = 140 cases) in relation to healthy lifestyle. Twenty percent of participants had a healthy diet, 66% were physically active, 95% were nonsmokers, and 55% had low stress. Each 1-point increase in lifestyle score was associated with a 21% lower risk of GDM (95% confidence interval: 0.65, 0.96) after adjustment for age, race, and nulliparity. Adjustment for prepregnancy body mass index, prepregnancy physical activity, and prepregnancy smoking attenuated the associations slightly. Associations were similar in normal-weight and overweight/obese women. In this study, a composite measure of healthy lifestyle during early pregnancy was associated with substantially lower GDM risk. Public health messaging and interventions promoting multiple aspects of a healthy lifestyle during early pregnancy should be considered for GDM prevention.

Maternal Leisure Time Physical Activity and Infant Birth Size.

BACKGROUND: Associations of maternal leisure time physical activity with birth size are inconsistent. Roles of infant sex and maternal prepregnancy body mass index (BMI) in these associations have not been studied. METHODS: Participants (N = 3,310) in the Omega study, a cohort in Washington State (1996-2008), reported leisure time physical activity duration and energy expenditure in the year prepregnancy and in early pregnancy (mean 15 weeks gestation). Regression models estimated mean differences in infant head circumference, birthweight, and ponderal index (birthweight/length) across quartiles of pre- or early-pregnancy leisure time physical activity. We assessed effect modification by infant sex or prepregnancy overweight/obese status (BMI ≥ 25 kg/m). RESULTS: We observed positive associations between prepregnancy leisure time physical activity and head circumference overall and among male infants. Among males, each quartile increase in prepregnancy physical activity duration was associated with 0.14 cm (95% confidence interval = 0.046, 0.24; trend P = 0.004) greater head circumference. We did not observe associations between leisure time physical activity and birthweight or ponderal index overall. Each quartile increase in pre- or early-pregnancy physical activity duration was associated with 17-23 g lower birthweight among female infants and among women with normal prepregnancy BMI. CONCLUSIONS: We observed positive associations between prepregnancy leisure time physical activity and head circumference among male infants, and inverse associations of pre- and early-pregnancy physical activity with birthweight among female infants and women with normal prepregnancy BMI. Future studies should confirm results and elucidate mechanisms of observed associations.

Association of serum vitamin D with symptoms of depression and anxiety in early pregnancy.

UNLABELLED: Abstract Objective: To evaluate associations between early pregnancy 25-hydroxyvitamin D (25[OH]D) concentrations and antepartum depression and anxiety symptoms and potential modifiers thereof. MATERIALS AND METHODS: In a pregnancy cohort (N=498), we examined cross-sectional associations of early pregnancy (mean=15.4 weeks gestation) serum 25[OH]D concentrations and depression and anxiety symptoms. Symptoms were measured using Depression, Anxiety, and Stress Scales (DASS-21) and Patient Health Questionnaire Depression Module (PHQ-9) instruments. Regression models were fit and effect modification by prepregnancy body mass index and leisure-time physical activity (LTPA) were assessed using interaction terms and stratified analyses. RESULTS AND DISCUSSION: Mean 25[OH]D concentration was 34.4 ng/mL. Approximately 12% had "moderate" anxiety (score ≥ 10) and depression (score ≥ 10) symptoms by DASS-21 Anxiety and PHQ-9 instruments, respectively. A 1 ng/mL lower 25[OH]D was associated with 0.043 and 0.040 higher DASS-21 Anxiety and PHQ-9 Scores (p-values=0.052 and 0.029, respectively). Participants in the lowest quartile of 25[OH]D (<28.9 ng/mL) had 1.11 higher PHQ-9 scores than those in the highest quartile (≥ 39.5 ng/mL, p<0.05). However, associations were attenuated and statistically insignificant in fully adjusted models. Inverse associations of 25[OH]D with depression symptoms were significant among participants who reported no LTPA, but not among women who reported any LTPA (interaction p=0.018). CONCLUSIONS: Our study provides modest evidence for inverse cross-sectional associations of early pregnancy maternal vitamin D concentrations with antepartum depression symptoms. We also observed that these associations may be modified by physical activity.

The association of maternal adult weight trajectory with preeclampsia and gestational diabetes mellitus.

BACKGROUND: Preeclampsia (PE) and gestational diabetes mellitus (GDM) adversely affect pregnancy outcomes and the subsequent health of both mother and infant. It is known that elevated pre-pregnancy body mass index (BMI) is associated with increased risk of these obstetrical complications. However, little is known about the role of adult weight patterns prior to pregnancy. METHODS: Self-reported weight at ages prior to the current pregnancy was recorded in a prospective cohort study of 3567 pregnant women, allowing assessment of longitudinal pre-pregnancy weight trajectories and their association with subsequent PE and GDM in the study pregnancy. RESULTS: Women who would subsequently experience PE or GDM in the study pregnancy experienced on average almost double the rate of adult weight gain than other women [PE: additional 0.30 kg/year, 95% confidence interval (CI) 0.09, 0.51 and GDM: additional 0.34 kg/year, 95% CI 0.21, 0.48]. Women with mean adult annual weight gain above the 90th percentile (1.4 kg/year) had elevated risk of subsequent PE and GDM independent of their BMI at age 18 and of their obesity status at the time of the study pregnancy. Finite mixture trajectory modelling identified four monotonely ordered, increasing mean weight trajectories. Relative to the second lowest (most common) weight trajectory, women in the highest trajectory were at greater risk of PE [odds ratio (OR) 5.0, 95% CI 2.9, 8.8] and GDM (OR 2.8, 95% CI 1.7, 4.5). CONCLUSIONS: These results indicate that higher adult weight gain trajectories prior to pregnancy may play a role in predisposing women to PE or GDM.

Maternal birthweight is associated with subsequent risk of vitamin D deficiency in early pregnancy.

BACKGROUND: Maternal low birthweight and vitamin D deficiency in pregnancy are associated with a similar spectrum of adverse pregnancy outcomes including pre-eclampsia and gestational diabetes. However, the relationship between maternal birthweight and subsequent vitamin D concentrations in early pregnancy is largely unknown. METHODS: We assessed whether self-reported maternal birthweight was associated with risk of early pregnancy vitamin D deficiency (≤20 ng/mL) among a pregnancy cohort (n = 658). Serum 25-hydroxyvitamin D [25(OH)D] was measured using liquid chromatography-tandem mass spectroscopy. RESULTS: Adjusting for maternal characteristics and month of blood draw, a 100-g higher maternal birthweight was associated with a 5.7% decreased risk of early pregnancy 25(OH)D deficiency [odds ratio (OR) = 0.94; 95% confidence interval (CI) 0.90, 0.99]. Low-birthweight (<2500 g) women were 3.7 times as likely to have early pregnancy 25(OH)D deficiency compared with normal-birthweight women [OR = 3.69; 95% CI 1.63, 8.34]. These relationships were not modified by either pre-pregnancy overweight status [body mass index (BMI) ≥25 kg/m(2)] or adulthood weight trajectory (BMI change ≥2 kg/m(2) from age 18 to pre-pregnancy). CONCLUSIONS: Further research on shared developmental mechanisms that determine birthweight and vitamin D homeostasis may help identify targets and related preventative measures for adverse pregnancy and birth outcomes.

Trimester-specific blood pressure levels and hypertensive disorders among pregnant migraineurs.

OBJECTIVE: We evaluated the influence of physician-diagnosed migraine on blood pressure levels and the risk of hypertensive disorders of pregnancy in a clinic-based prospective cohort study of 3373 healthy pregnant women. BACKGROUND: The relationship between migraine and blood pressure is controversial with results from several studies suggesting positive associations, while others suggest null or inverse associations. To our knowledge, no previous study has investigated blood pressure profiles among pregnant migraineurs. METHODS: We abstracted blood pressure values and delivery information from medical records of women presenting to prenatal clinics in Washington State. Mean blood pressure differences for pregnant migraineurs and non-migraineurs were estimated in regression models, using generalized estimating equations. We calculated odds ratios and 95% confidence intervals (95% CIs) for gestational hypertension and preeclampsia in relation to migraine status. RESULTS: Mean first, second, and third trimester systolic blood pressures (SBP) were elevated among pregnant migraineurs as compared with non-migraineurs. Migraineurs had higher mean third trimester SBP (4.08 mmHg) than non-migraineurs. Trimester-specific diastolic blood pressure (DBP) values were variably related with migraine status. Mean first (0.82 mmHg) and third (2.39 mmHg) trimester DBP were higher, and second trimester DBP values were lower (-0.24) among migraineurs as compared with non-migraineurs. Migraineurs had a 1.53-fold increased odds of preeclampsia (95% CI 1.09 to 2.16). Additionally, migraineurs who were overweight or obese had a 6.10-fold increased odds of preeclampsia (95% CI 3.83 to 9.75) as compared with lean non-migraineurs. CONCLUSIONS: Pregnant migraineurs had elevated blood pressures, particularly SBP measured in the third trimester, and a higher risk of preeclampsia than pregnant women without migraine. Observed associations were more pronounced among overweight or obese migraineurs. Our findings add to the accumulating evidence of adverse pregnancy outcomes among migraineurs.

Age at menarche, menstrual characteristics, and risk of preeclampsia.

We examined associations of age at menarche and menstrual characteristics with the risk of preeclampsia among participants (n = 3,365) of a pregnancy cohort study. Data were collected using in-person interviews and medical record abstraction. Logistic regression was used to estimate adjusted odds ratio (OR) and 95% confidence interval (95% CI). There was a significant inverse association between age at menarche and risk of preeclampsia (P value for trend < 0.05). Association of long cycle length (>36 days) with higher risk of preeclampsia was present only among women who had prepregnancy body mass index <25 kg/m(2) (interaction P value = 0.04). Early menarche is associated with higher risk of preeclampsia. Prepregnancy weight may modify associations of long menstrual cycles with risk of preeclampsia.

Associations of early pregnancy sleep duration with trimester-specific blood pressures and hypertensive disorders in pregnancy.

STUDY OBJECTIVES: We evaluated the influence of maternal self-reported habitual sleep duration during early pregnancy on blood pressure (BP) levels and risk of hypertensive disorders of pregnancy. DESIGN: Prospective cohort study. SETTING: Clinic-based study. PARTICIPANTS: A cohort of 1,272 healthy, pregnant women. MEASUREMENTS AND RESULTS: We abstracted maternal antenatal BP values from medical records and estimated mean BP differences across hours of sleep categories in regression models, using generalized estimating equations. Odds ratios (OR) and 95% confidence intervals (95% CIs) for pregnancy induced hypertension (PIH) and preeclampsia (PE) in relation to long and short sleep duration were estimated. Mean 1st and 2nd trimester systolic (S) and diastolic (D) BP values were similar among women reporting to be short sleepers (< or = 6 h) vs. women reporting to sleep 9 hours. However, both short and long sleep duration in early pregnancy were associated with increased mean 3rd trimester SBP and DBP. For example, mean 3rd trimester SBP was 3.72, and 2.43 mm Hg higher for women reporting < or = 6 h and 7-8 h sleep, respectively, compared with women reporting 9 h of sleep. Mean 3rd trimester SBP was 4.21 mm Hg higher for women reporting long sleep (> or = 10 h) vs. the reference group. Short and long sleep durations were associated with increased risks of PIH and PE. The ORs for very short (< 5 h) and long (> or = 10 h) sleepers were 9.52 (95% CI 1.83 to 49.40) and 2.45 (95% CI 0.74 to 8.15) for PE. CONCLUSIONS: Our findings are consistent with a larger literature that documents elevated blood pressure and increased risks of hypertension with short and long sleep duration.

Modelling the association of blood pressure during pregnancy with gestational age and body mass index.

Improved understanding of the determinants of blood pressure (BP) changes during pregnancy is essential for decreasing the morbidity and mortality borne by women and their families worldwide. While most epidemiological studies consider associations based on categorical risk factor classifications, using measurements on a continuous scale has been advocated as a means of gaining richer insights into biological processes. We modelled the relationship during pregnancy of continuous systolic (S) and diastolic (D) BP distributions with gestational age and pre-pregnancy body mass index (BMI) using fractional polynomials. We used information, including antenatal BP values abstracted from medical records, from a prospective cohort of 1733 women recruited before 20 weeks' gestation. The percentiles for SBP and DBP changed over pregnancy, with DBP percentiles decreasing initially, followed by an increase starting about mid-second trimester. Modelling the joint impact of BMI and gestational age on mean BP indicated an increase in mean BP with increasing BMI that was attenuated at higher BMI levels, later in pregnancy. This attenuation persisted in a variety of sub-analyses which explored the possibility that it was caused by confounding or by influential groupings of subjects. Estimated longitudinal percentiles that characterise the BP distribution across gestation may facilitate evaluation of BP during pregnancy. BP patterns observed over pregnancy and, in particular, the attenuation of BP increases at high BMI, late in pregnancy, can provide insights towards elucidating the mechanisms that drive BP changes during pregnancy.

Iron deficiency anemia, cigarette smoking and risk of abruptio placentae.

AIM: A higher frequency of abruptio placentae among anemic patients has been documented in some, but not all previously published studies. Altered feto-placental angiogenesis during early pregnancy in anemic women may partially explain this increased risk. The present study assesses the iron deficiency anemia-abruptio placentae association in pregnant women from the Pacific Northwest. METHODS: A retrospective case-control study of 145 abruptio placentae cases and 1710 control subjects was conducted. The diagnosis of abruptio placentae was based on routine clinical examination performed by attending physicians. Iron deficiency anemia was assessed in early pregnancy and defined as hemoglobin level <10 g/dL or by physician diagnosis. Information on maternal sociodemographic characteristics, cigarette smoking status during pregnancy and reproductive history was abstracted from medical records. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) after adjusting for confounders. RESULTS: Eleven percent of abruptio placentae cases and 3.3% of controls were diagnosed with iron deficiency anemia. Maternal iron deficiency anemia in early pregnancy was associated with a 3.60-fold increased risk of abruptio placentae (95% CI 2.01-6.04). After adjusting for maternal age, gravidity, smoking during pregnancy, Medicaid payment status, and pre-gestational hypertension, the association was attenuated but remained statistically significant (adjusted OR = 2.40; 95% CI 1.22-4.73). Maternal smoking during pregnancy was associated with a 2.40-fold increased risk of abruptio placentae (95% CI 1.19-3.52). The iron deficiency anemia-abruptio placentae association was not modified by maternal smoking. CONCLUSION: Our results support the hypothesis that maternal iron deficiency anemia is associated with an increased risk of abruptio placentae.

Construction and characterisation of a longitudinal clinical blood pressure database for epidemiological studies of hypertension in pregnancy.

Blood pressure measurement plays a central role in the screening and management of hypertension during pregnancy. Although descriptions of changes in blood pressure patterns of normotensive and hypertensive pregnancies are plentiful, relatively little is known about how modifiable environmental and lifestyle characteristics, including maternal diet and physical activity, influence blood pressure levels in pregnancy. In this paper we provide a detailed description of the first 2000 subjects enrolled in the Omega Prospective Cohort Study. Our intention is to characterise the cohort and to establish a rigorous data framework that will form the basis for future analyses of the association between blood pressure patterns in pregnancy and modifiable risk factors. We describe the construction of a representative longitudinal blood pressure analysis database drawn from routinely collected measurements. In doing this, we explore possible over- and under-representation of patients and evaluate ways of modifying the database to address areas of possible bias. In addition, we consider questions of data quality which are specific to blood pressure measurements. In an accompanying paper, we use this database to explore the influence of maternal pre-pregnancy adiposity on blood pressure levels across gestation.

Trimester-specific blood pressure levels in relation to maternal pre-pregnancy body mass index.

We evaluated the influence of maternal pre-pregnancy body mass index (BMI), based on reported pre-pregnancy weight and height, on blood pressure (BP) levels during pregnancy by using information from a prospective cohort of 1733 women recruited before 20 weeks' gestation. Maternal antenatal BP values were abstracted from medical records, and we evaluated the mean BP differences according to BMI group in regression models, using generalised estimating equations to account for repeated BP records within each pregnancy. In each trimester, mean systolic BP (SBP) and diastolic BP (DBP) values were positively associated with maternal pre-gestational BMI. This association persisted after adjustment for maternal age, parity, smoking, education, marital status and physical activity. Overweight women (25-29 kg/m(2)) had first-, second- and third-trimester mean SBPs that were 8.1, 7.7 and 8.2 mmHg, respectively, higher than values observed in lean women (<20 kg/m(2)). Mean DBP values were 4.5, 5.4 and 5.6 mmHg higher for each successive trimester in overweight vs. lean women. Obese (>30 kg/m(2)) women consistently had the highest mean SBP and DBP values. Trimester-specific mean SBP values were 10.7-12.0 mmHg higher among obese women vs. lean women. Corresponding trimester-specific mean DBP values were 6.9-7.4 mmHg higher in obese vs. lean women. Similar patterns were observed when trimester-specific average mean arterial pressures were evaluated. Elevated pregnancy BPs associated with maternal pre-gestational BMI are consistent with a large body of literature that documents increased pre-eclampsia risk among overweight and obese women.

First-trimester mean arterial pressure and risk of preeclampsia.

BACKGROUND: Maternal second-trimester mean arterial pressure (MAP) is associated with a risk of preeclampsia in some but not all published studies. We examined average first-trimester MAP in relation to preeclampsia risk among 1655 women. METHODS: Using blood-pressure measurements recorded during prenatal care, we calculated MAP, and averaged the values within the first trimester. We defined preeclampsia according to national criteria, using information abstracted from medical records. We classified participants by MAP quartiles: <79, 79-83, 84-88, and >or=89 mm Hg. We calculated risk ratios (RRs) and 95% confidence intervals (CIs) adjusted for prepregnancy body mass index, age, race/ethnicity, and parity. RESULTS: High-quartile MAP was associated with an increased risk of preeclampsia when using current diagnostic criteria (adjusted RR versus low-quartile, 3.0; 95% CI, 1.2-7.4) but not when using older criteria (RR, 1.2; 95% CI, 0.6-2.2). First-trimester MAP did not strongly predict future preeclampsia (area under the receiver operating curve, 0.71). A MAP >/=88 mm Hg predicted preeclampsia with a sensitivity of 0.78 and a specificity of 0.63. CONCLUSIONS: Although first-trimester MAP is strongly associated with risk of preeclampsia, it poorly discriminates between women who will and will not develop the disease.

Adult weight change, weight cycling, and prepregnancy obesity in relation to risk of preeclampsia.

BACKGROUND: Preeclampsia has been shown to be associated with obesity, with other risk factors for cardiovascular disease, and with subsequent cardiovascular disease itself. However, the possible association with weight gain and weight cycling has not been evaluated. METHODS: In this prospective study of a cohort of 1644 pregnant women, we assessed adult weight change, intentional weight cycling, and prepregnancy obesity in relation to preeclampsia risk. Net weight change from age 18 years to the period 3 months before conception was determined for each participant. Weight cycling was defined as intentional weight loss and unintentional regain of at least 15 pounds during periods not related to pregnancy or lactation. We used multivariate regression procedures to calculate risk ratios (RRs) and 95% confidence intervals (CIs). RESULTS: Relative to women with stable weight (gained or lost < 2.5 kg) women who gained 5.0-9.9 kg experienced a 2.6-fold increased risk of preeclampsia (95% CI = 1.0-6.7). The corresponding risk ratio (RR) for women who gained > or = 10 kg was 5.1 (2.2-12.2). Intentional weight cycling, after controlling for weight at age 18 years, adult weight change, and other risk factors, was not associated with increased risk of preeclampsia (RR = 1.1; CI = 0.6-1.8). RRs increased monotonically with increasing prepregnancy body mass index greater than 19.8 kg/m. After adjusting for confounders, the RR for prepregnancy overweight women and obese women were 1.7 (0.6-4.9) and 3.4 (1.5-7.6) respectively. CONCLUSIONS: These results suggest that adult weight gain and prepregnancy overweight and obesity status are associated with an increased risk of preeclampsia.

Perceived exertion in physical activity and risk of gestational diabetes mellitus.

BACKGROUND: Physical activity has been associated with decreased risk of gestational diabetes mellitus. Expanding on 2 previously published analyses of absolute exertion measures (time spent and energy expended), we assessed the relation between perceived exertion during usual prepregnancy recreational physical activity and gestational diabetes. METHODS: We analyzed data from a Washington State 1998-2002 case-control study (216 cases, 472 controls) and a 1996-2002 prospective cohort study (897 participants) separately. We used logistic regression models to derive odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Among case-control participants, risk of gestational diabetes was markedly lower for women who reported very strenuous to maximal exertion in usual activity during the year before pregnancy versus those who reported negligible or minimal exertion (adjusted OR = 0.19; CI = 0.15-0.50). There was a direct inverse relation between perceived exertion and risk of gestational diabetes. This relation was also evident among the subset of participants who did not meet physical activity guidelines in the year before pregnancy. Similarly, the OR among cohort participants reporting very strenuous to maximal exertion was 0.57 (0.24-1.37) versus those reporting negligible to moderate exertion. CONCLUSIONS: These results suggest that risk of gestational diabetes is inversely related to the exertion perceived during recreational physical activity in the year before pregnancy. Perceived exertion may be a valuable addition to behavior and fitness measures in assessing relations between physical activity and pregnancy-related health outcomes.

Risk of preeclampsia in relation to maternal history of migraine headaches.

OBJECTIVE: We examined the relationship between migraines and preeclampsia risk. STUDY DESIGN: Cases were 244 women with preeclampsia and controls were 470 normotensive women. Women were asked if a physician had ever told them that they had migraines. Odds ratios (OR) and 95% confidence intervals (CI) were calculated. RESULTS: A history of migraines was associated with a 1.8-fold increased risk of preeclampsia (95% CI 1.1-2.7). Women who were 30+ years old when diagnosed with migraines had the highest risk (OR 2.8, 95% CI 0.8-9.0). The migraine-preeclampsia association appeared to be modified by pre-pregnancy overweight status (p = 0.06). Overweight migrainous women, compared with lean nonmigrainous women, had a 12-fold increased preeclampsia risk (95% CI 5.9-25.7). CONCLUSION: Our findings are consistent with reports from six of eight previous studies on the topic. Nevertheless, prospective cohort studies are needed to further evaluate the extent to which migraines and/or its treatments are associated with preeclampsia risk.

Perceived exertion during prepregnancy physical activity and preeclampsia risk.

PURPOSE: Studies have shown that absolute intensity of physical activity is associated with reduced risk of preeclampsia. This analysis was performed to examine whether relative intensity may also be related to preeclampsia risk. METHODS: Using data from a case-control study conducted from 1998 to 2002, the authors assessed the relation between perceived exertion (i.e., relative intensity) during usual recreational physical activity in the year before pregnancy and risk of preeclampsia. In a structured interview conducted during postpartum hospitalization, 244 preeclampsia cases and 470 normotensive controls provided details on their recreational physical activities in the year before pregnancy. RESULTS: Participants who reported feeling very strenuous to maximal exertion during usual prepregnancy physical activity were 78% less likely to have developed preeclampsia than those who reported negligible or minimal exertion (adjusted odds ratio 0.22, 95% confidence interval 0.11-0.44). A significant trend was noted of decreased preeclampsia risk with increased perceived exertion (P < 0.001). This association was independent of prepregnancy adiposity, and was also apparent among the subset of participants who did not meet physical activity guidelines in the year before pregnancy. CONCLUSIONS: In this study, relative intensity of recreational physical activity performed during the year before pregnancy was associated with a decreased risk of preeclampsia.

Maternal pre-pregnancy overweight status and obesity as risk factors for cesarean delivery.

OBJECTIVE: To determine the extent to which, if at all, maternal pre-pregnancy adiposity and other anthropometric factors are related to risk of cesarean delivery. METHODS: This hospital-based prospective cohort study included 738 nulliparous women who initiated prenatal care prior to 16 weeks gestation. Participants provided information about their pre-pregnancy weight and height and other sociodemographic and reproductive covariates. Labor and delivery characteristics were obtained from maternal and infant medical records. Risk ratios (RR) and 95% CI were estimated by fitting generalized linear models. RESULTS: The proportion of cesarean deliveries in this population was 26%. Women who were overweight (BMI 25.00-29.99 kg/m2) were twice as likely to deliver their infants by cesarean section as lean women (BMI<20.00 kg/m2) (RR=2.09; 95% CI 1.27-3.42). Obese women (BMI>or=30.00 kg/m2) experienced a three-fold increase in risk of cesarean delivery when compared with this referent group (RR=3.05; 95% CI 1.80-5.18). The joint association between maternal pre-pregnancy overweight status and short stature was additive. When compared with tall (height>or=1.63 m), lean women, short (<1.63 m), overweight (BMI>or=25.00 kg/m2) women were nearly three times as likely to have a cesarean delivery (RR=2.79; 95% CI 1.72-4.52). CONCLUSION: Our findings suggest that nulliparous women who are overweight or obese prior to pregnancy, and particularly those who are also short, have an increased risk of delivering their infants by cesarean section.

A case-control study of maternal recreational physical activity and risk of gestational diabetes mellitus.

Despite the maternal and infant morbidity associated with gestational diabetes mellitus (GDM), few modifiable risk factors have been identified. We explored the relation between recreational physical activity performed during the year before and during the first 20 weeks of pregnancy and the risk of GDM. 155 GDM cases and 386 normotensive, non-diabetic pregnant controls provided information about the type, intensity, frequency, and duration of physical activity performed during these time periods. Women who participated in any recreational physical activity during the first 20 weeks of pregnancy, as compared with inactive women, experienced a 48% reduction in risk of GDM (odds ratio [OR] = 0.52; 95% confidence interval [CI] 0.33-0.80). The number of hours spent performing recreational activities and the energy expended were related to a decrease in GDM risk. No clear patterns related to distance walked and pace of walking emerged. Daily stair climbing, when compared with no stair climbing, was associated with a 49-78% reduction in GDM risk (P for trend <0.011). Recreational physical activity performed during the year before the index pregnancy was also associated with statistically significant reductions in GDM risk, but women who engaged in physical activity during both time periods experienced the greatest reduction in risk (OR = 0.40; 95% CI 0.23-0.68). These data suggest that recreational physical activity performed before and/or during pregnancy is associated with a reduced risk of GDM.