Exercise as it relates to Disease/Can exercise during pregnancy reduce the risk of a miscarriage?

This is an analysis and evaluation of the research paper by Mary Latka, Jennie Kline and Maureen Hatch; Latka M, Kline J, Hatch M. Exercise and spontaneous abortion of known karyotype. Epidemiology. 1999 Jan 1:73-5.

Research Background
Miscarriages affect on average 10% of pregnancies worldwide and are thought to affect up to 31% of pregnancies in nonclinical instances. Recreational exercise has been identified to have a number of health benefits including reduced mortality risk, increased MPS, decreased risk of cancer, improved bone health, improved cardiorespiratory health, increased muscle mass, decreased body fat, improved metabolic fitness, and improved blood volume. In recent years, exercise recommendations for women during pregnancy have presented multiple health benefits including improved neurodevelopment of the child, improved fetal development and volume, improved self-image of the mother, improved maternal fitness, and reduced risk lower back pain. With emerging research identifying recreational exercise as a method to reduce health-related risks of the mother and child, a recent research paper by Mary Latka, Jennie Kline, and Maureen Hatchwas conducted in 1992-1996 to examine the use of recreational exercise as a method to reduce the risk of a miscarriage during pregnancy.

Research origin
The research was conducted by Mary Latka, Jennie Kline, and Maureen Hatchin at the New York Academy of Medicine, C.U.E.S. Room 556, New York, NY 100 in 1996. Funding and publishing were supported by the JSTOR library with the publishing of the research paper taking place in Jan.1999

Research Type
The research was completed using a case-control, longitudinal self-reported questionnaire study. Participants were initially chosen from public and private hospitals, but the low prevalence of participants that exercised in the public healthcare group caused research to be completed only on private healthcare participants. This should be considered throughout the study with such a low prevalence of pregnant mothers completing leisure exercise throughout pregnancy. Participants completed questionnaires 15 days after a miscarriage (average 92.6 days between questionnaires)or during gestation (average 182.8 days between questionnaires). Results were collated using a logistic regression model to create an estimation of the odds ratios of exercise and the prevalence of abortions for chromosomally normal and chromosomally aberrant groups. The use of a regression model should be considered when examining results with the awareness that results are an estimation on the effect of exercise on a premature miscarriage and not collected data.

Research Methodology
The research was conducted on 346 pregnant private healthcare patients from a Private, New York City Hospital in America. For the 346 patients omitted to the study, two groups were separated and compared throughout the study; 173 Chromosomally normal abortions 173 Chromosomally aberrant abortions Each participant was questioned on any physical activity completed throughout their week and categorized their activity types from their chromosomal group based on; Exercise status and type Do they complete any standing at work Are they Employed, how many hours do they work Are they a Childcare worker, how much work do they complete Do they Complete housework throughout the week and how much Issues relating to the use of self-reported questionnaires as the data collection method should be considered throughout the study. Although self-reported questionnaires are a fast and efficient method to collect data with a large cohort group, the tendency of participants to overexaggerate values can overinflate results.

Basic Results
25% of the 346 sampled participants involved in the study completed exercise throughout their pregnancy consisting of jogging (38%), aerobics (37%), swimming (42%), and inadvertent exercise while working; >35 hrs/wk Standing (8%), >10hrs/wk housework (7.2%) Results indicated that leisure-time exercise such as walking, running, rowing, swimming and incidental exercise during work was a protective factor against Chromosomally normal and different abortion (Odds ratio = 0.6, 95% CI 0.3–0.9). This indicates that general, unprogrammed physical activity can benefit the risks related to chromosomally normal and afferent abortions.

Note; ^ = Have never previously had an abortion before
 * = Have previously had an abortion

The use of questionnaires are generally low expense methods to evaluate the physical activity completed by patients throughout the pregnancy, however, problems arise related to the information provided on the number of physical activity participants completed per week. The chosen participants used in the physical activity group did not have a structured program to assess the effect of training type, intensity, and duration of training completed per week. This caused participants who all had exercise durations, intensities, and exercise types to be grouped into the same exercise cohort. The lack of structured programming affects the information provided on recommended Physical activity for pregnant women and the degree of effect exercise on reducing a miscarriage. Further studies should be completed to identify the best type of training to reduce the risk of miscarriages.

Research Conclusions
Based on the research results provided, we can conclude sedentary exercise can reduce the risk of miscarriages in non-chromosomally and chromosomally normal cohorts. These exercise types include; aerobic exercise, walking, jogging, swimming, housework, gardening, cycling. Further research should be completed to evaluate the effect of work-related exercise such as standing and resistance exercise as a method to reduce the risk of a miscarriage. Further research should also be complete to evaluate the best training prescription method to reduce the risks of a miscarriage, these include training type, training frequency, and training intensity,.

Practical Advice
Using exercise as a generally low-cost method to assist health practitioners, general practitioners, and obstetricians in reducing the risks associated with pregnancy would be a largely beneficial non-clinical method related to pregnancy if the appropriate exercise prescription is discovered. In conclusion, further research to identify the most appropriate exercise prescription at varying stages of pregnancy to improve the health of the mother and fetus should be made prior to practical application.