This review aims to provide an update on the recent evidence concerning exercise during pregnancy including effects for mother and fetus and the types, frequency, intensity, duration and rate of progression of exercise performed. Exercises during pregnancy are associated with higher cardiorespiratory fitness, prevention of urinary incontinence and low back pain, reduced symptoms of depression, gestational weight gain control, and for cases of gestational diabetes, reduced number of women who required insulin. There is no association with reduction in birth weight or preterm birth rate. The type of exercise shows no difference on results, and its intensity should be mild or moderate for previous sedentary women and moderate to high for active women. The exercise recommendations still are based on the current guidelines on moderate-intensity, low-impact, aerobic exercise at least three times a week. Yet, new guidelines propose increasing weekly physical-activity expenditure while incorporating vigorous exercise and adding light strength training to the exercise routine of healthy pregnant women. In the case of other chronic diseases like hypertension, there are still few data, and therefore more studies should be performed to assess the safety of the intervention. Physical exercise is beneficial for women during pregnancy and also in the postpartum period; it is not associated with risks for the newborn and can lead to changes in lifestyle that imply long-term benefits.

Background: Diet- and physical activity-based interventions in pregnancy have the potential to alter maternal and child outcomes.Objectives: To assess whether or not the effects of diet and lifestyle interventions vary in subgroups of women, based on maternal body mass index (BMI), age, parity, Caucasian ethnicity and underlying medical condition(s), by undertaking an individual patient data (IPD) meta-analysis. We also evaluated the association of gestational weight gain (GWG) with adverse pregnancy outcomes and assessed the cost-effectiveness of the interventions.Data sources: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects and Health Technology Assessment database were searched from October 2013 to March 2015 (to update a previous search).Review methods: Researchers from the International Weight Management in Pregnancy Collaborative Network shared the primary data. For each intervention type and outcome, we performed a two-step IPD random-effects meta-analysis, for all women (except underweight) combined and for each subgroup of interest, to obtain summary estimates of effects and 95% confidence intervals (CIs), and synthesised the differences in effects between subgroups. In the first stage, we fitted a linear regression adjusted for baseline (for continuous outcomes) or a logistic regression model (for binary outcomes) in each study separately; estimates were combined across studies using random-effects meta-analysis models. We quantified the relationship between weight gain and complications, and undertook a decision-analytic model-based economic evaluation to assess the cost-effectiveness of the interventions.Results: Diet and lifestyle interventions reduced GWG by an average of 0.70 kg (95% CI –0.92 to –0.48 kg; 33 studies, 9320 women). The effects on composite maternal outcome [summary odds ratio (OR) 0.90, 95% CI 0.79 to 1.03; 24 studies, 8852 women] and composite fetal/neonatal outcome (summary OR 0.94, 95% CI 0.83 to 1.08; 18 studies, 7981 women) were not significant. The effect did not vary with baseline BMI, age, ethnicity, parity or underlying medical conditions for GWG, and composite maternal and fetal outcomes. Lifestyle interventions reduce Caesarean sections (OR 0.91, 95% CI 0.83 to 0.99), but not other individual maternal outcomes such as gestational diabetes mellitus (OR 0.89, 95% CI 0.72 to 1.10), pre-eclampsia or pregnancy-induced hypertension (OR 0.95, 95% CI 0.78 to 1.16) and preterm birth (OR 0.94, 95% CI 0.78 to 1.13). There was no significant effect on fetal outcomes. The interventions were not cost-effective. GWG, including adherence to the Institute of Medicine-recommended targets, was not associated with a reduction in complications. Predictors of GWG were maternal age (summary estimate –0.10 kg, 95% CI –0.14 to –0.06 kg) and multiparity (summary estimate –0.73 kg, 95% CI –1.24 to –0.23 kg).Limitations: The findings were limited by the lack of standardisation in the components of intervention, residual heterogeneity in effects across studies for most analyses and the unavailability of IPD in some studies.Conclusion: Diet and lifestyle interventions in pregnancy are clinically effective in reducing GWG irrespective of risk factors, with no effects on composite maternal and fetal outcomes.Future work: The differential effects of lifestyle interventions on individual pregnancy outcomes need evaluation.Study registration: This study is registered as PROSPERO CRD42013003804.Funding: The National Institute for Health Research Health Technology Assessment programme.

To assess the physical activity levels of pregnant women and to examine the characteristics associated with the practice of exercise and the activities of daily living during pregnancy. For this cross-sectional study, 1,279 women were recruited within 72 hours postpartum. They were interviewed about their socio-demographic data and obstetric history and were administered self-report questionnaires about exercise and daily physical activities during pregnancy. Data on the current pregnancy, labor, delivery, and newborn outcomes were collected from participants’ medical records. To analyze factors related to the practice of exercise, we used the student t-test, X², and odds ratio (OR), with a corresponding 95% confident interval (CI), followed by a multiple logistic regression. The significance level was 5%. Compared to the pre-pregnancy period, the prevalence of physical activity among participants was lower throughout pregnancy (20.1%) (p = 0.01). Half of the women interrupted practicing physical exercise due to pregnancy. The lowest prevalence of exercise was observed in the first (13.6%) and third trimesters (13.4%). Less than half of women received exercise guidance during prenatal care meetings (47.4%). Walking was the most commonly reported exercise, followed by water aerobics. Factors positively associated with exercise practice were higher educational level (OR= 1.82; CI 95% 1.28–2.60), primiparity (OR=1.49; CI 95% 1.07–2.07), exercising before pregnancy (OR= 6.45; CI 95% 4.64–8.96), and exercise guidance during prenatal care (OR=2.54; CI 95% 1.80–3.57). Mildly intense exercise and domestic activities were most frequently reported among pregnant women. There were no differences in maternal and perinatal outcomes between active and sedentary pregnant women. The findings indicate that promoting physical activity remains a priority in public health policy, and women of childbearing age, especially those planning a pregnancy, should be encouraged to adopt an exercise routine or maintain an active lifestyle during pregnancy in order to avoid sedentary- and obesity-associated risks.

Twin pregnancy was associated with significantly higher rates of adverse neonatal and perinatal outcomes, especially for the second twin. In addition, the maternal complications (potentially life-threatening conditions-PLTC, maternal near miss-MNM, and maternal mortality-MM) are directly related to twin pregnancy and independently associated with adverse perinatal outcome. The objective of the preset study is to evaluate perinatal outcomes associated with twin pregnancies, stratified by severe maternal morbidity and order of birth. Secondary analysis of the WHO Multicountry Survey on Maternal and Newborn Health (WHOMCS), a cross-sectional study implemented in 29 countries. Data from 8568 twin deliveries were compared with 308,127 singleton deliveries. The occurrence of adverse perinatal outcomes and maternal complications were assessed. Factors independently associated with adverse perinatal outcomes were reported with adjusted PR (Prevalence Ratio) and 95%CI. The occurrence of severe maternal morbidity and maternal death was significantly higher among twin compared to singleton pregnancies in all regions. Twin deliveries were associated with higher rates of preterm delivery (37.1%), Apgar scores less than 7 at 5th minute (7.8 and 10.1% respectively for first and second twins), low birth weight (53.2% for the first and 61.1% for the second twin), stillbirth (3.6% for the first and 5.7% for the second twin), early neonatal death (3.5% for the first and 5.2% for the second twin), admission to NICU (23.6% for the first and 29.3% for the second twin) and any adverse perinatal outcomes (67% for the first twin and 72.3% for the second). Outcomes were consistently worse for the second twin across all outcomes. Poisson multiple regression analysis identified several factors independently associated with an adverse perinatal outcome, including both maternal complications and twin pregnancy. Twin pregnancy is significantly associated with severe maternal morbidity and with worse perinatal outcomes, especially for the second twin.

High Body Mass Index (BMI) and gestational weight gain (GWG) affect an increasing number of pregnancies. The Institute of Medicine (IOM) has issued recommendations on the optimal GWG for women according to their pre-pregnancy BMI (healthy, overweight or obese). It has been shown that pregnant women rarely met the recommendations; however, it is unclear by how much. Previous studies also adjusted the analyses for various women’s characteristics making their comparison challenging. We analysed individual participant data (IPD) of healthy women with a singleton pregnancy and a BMI of 18.5 kg/m2 or more from the control arms of 36 randomised trials (16 countries). Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were used to describe the association between GWG outside (above or below) the IOM recommendations (2009) and risks of caesarean section, preterm birth, and large or small for gestational age (LGA or SGA) infants. The association was examined overall, within the BMI categories and by quartile of GWG departure from the IOM recommendations. We obtained aOR using mixed-effects logistic regression, accounting for the within-study clustering and a priori identified characteristics. Out of 4429 women (from 33 trials) meeting the inclusion criteria, two thirds gained weight outside the IOM recommendations (1646 above; 1291 below). The median GWG outside the IOM recommendations was 3.1 kg above and 2.7 kg below. In comparison to GWG within the IOM recommendations, GWG above was associated with increased odds of caesarean section (aOR 1.50; 95%CI 1.25, 1.80), LGA (2.00; 1.58, 2.54), and reduced odds of SGA (0.66; 0.50, 0.87); no significant effect on preterm birth was detected. The relationship between GWG below the IOM recommendation and caesarean section or LGA was inconclusive; however, the odds of preterm birth (1.94; 1.31, 2.28) and SGA (1.52; 1.18, 1.96) were increased. Consistently with previous findings, adherence to the IOM recommendations seem to help achieve better pregnancy outcomes. Nevertheless, even in the context of clinical trials, women find it difficult to adhere to them. Further research should focus on identifying ways of achieving a healthier GWG as defined by the IOM recommendations.