This paper presents an overview of the application of and risks of exposure to Magnetic Resonance Imaging (MRI) in pregnancy. It reviews the risks to the fetus by considering the hazards in terms of the three main components of an MRI system. These are the static magnetic field, the time-varying magnetic gradient fields and the pulsed radio frequency fields. The hazards discussed are biological effects, miscarriage, heating effects and acoustic noise exposure. This paper also presents a survey of MRI sites within the United Kingdom to ascertain the extent of MRI usage in pregnancy. To validate the situation of MRI in pregnancy a survey was sent to 352 MR units throughout the United Kingdom. The questions were grouped to assess (a) maternal MRI diagnosis (b) fetal MRI and (c) work practices for pregnant MRI staff. The results showed that 91% of sites were imaging pregnant women in need of diagnosis in the second and third trimester. This paper highlights that MRI can add information for fetal central nervous system abnormalities identified by ultrasound screening, however within the UK direct fetal imaging was only performed in 8% of sites. This paper indicates the need for research to be undertaken for specific MRI clinical conditions. It also advises that risk assessment for pregnant staff working in MRI is performed, and that there is a clear need for further research into the effects of MRI in pregnancy as there is a need for clear authoritive advice.

Objective: The aim of this study was to estimate the risk of adverse birth outcomes for women who underwent nonobstetric surgery during pregnancy compared with those who did not. Background: Previous research suggests that nonobstetric surgery occurs during 1% to 2% of pregnancies. However, there is limited evidence quantifying risks to the mother or pregnancy of such surgery. Methods: We examined maternity admissions using hospital administrative data collected between April 1, 2002, and March 31, 2012, and identified pregnancies wherein nonobstetric surgery occurred. We used logistic regression models to determine the adjusted relative risk, attributable risk, and number needed to harm of nonobstetric surgical procedures for adverse birth outcomes. Results: We identified 6,486,280 pregnancies. In 47,628 of these pregnancies, nonobstetric surgery had occurred. We found that nonobstetric surgery during pregnancy was associated with a higher risk of adverse birth outcomes, although the attributable risk was generally low. We estimated that every 287 surgical operations were associated with 1 additional stillbirth, every 31 operations associated with 1 additional preterm delivery, every 39 operations associated with 1 additional low birth weight baby, every 25 operations associated with 1 additional caesarean section, and every 50 operations associated with 1 additional long inpatient stay. Conclusions: Although we have no means of disentangling the effect of the surgery from the effect of the underlying condition, we found that the risk associated with nonobstetric surgery was relatively low, confirming that surgical procedures during pregnancy are generally safe. We believe that our findings improve upon previous research, and are useful reference points for any discussion of risk with prospective patients.Keywords: complications, obstetric, pregnancy, safety, surgery (Ann Surg 2017;266:260-266) T raditional teaching states that there is an increased risk of miscarriage, stillbirth, and preterm labor when a pregnant woman undergoes surgery under general anesthesia during pregnancy.1 This risk has however never been quantified and such risks may have decreased with the use of modern anesthetic agents and techniques. At present, when counseling a pregnant woman on this risk, the information provided is not robustly evidence-based.Previous research suggests that 1% to 2 % of women undergo nonobstetric surgery during pregnancy, 2 common operations being appendicectomy, cancer surgery, and orthopedic procedures. Research has also suggested that nonobstetric surgery during pregnancy is associated with adverse birth outcomes: a Canadian study of 2565 pregnant women reported an increased risk of spontaneous abortion after a general anesthetic [relative risk (RR) ¼ 1.58, 95% confidence interval (95% CI) 1.19-2.09];3 and a Swedish registry study showed associations between nonobstetric operations during pregnancy and low birth weight. 4 A systematic review brought these and many smaller studies together.5 In this analy...

Background: Previous research suggests that non-obstetric surgery is carried out in 1 – 2% of all pregnancies. However, there is limited evidence quantifying the associated risks. Furthermore, of the evidence available, none relates directly to outcomes in the UK, and there are no current NHS guidelines regarding non-obstetric surgery in pregnant women. Objectives: To estimate the risk of adverse birth outcomes of pregnancies in which non-obstetric surgery was or was not carried out. To further analyse common procedure groups. Data Source: Hospital Episode Statistics (HES) maternity data collected between 2002 – 3 and 2011 – 12. Main outcomes: Spontaneous abortion, preterm delivery, maternal death, caesarean delivery, long inpatient stay, stillbirth and low birthweight. Methods: We utilised HES, an administrative database that includes records of all patient admissions and day cases in all English NHS hospitals. We analysed HES maternity data collected between 2002 – 3 and 2011 – 12, and identified pregnancies in which non-obstetric surgery was carried out. We used logistic regression models to determine the adjusted relative risk and attributable risk of non-obstetric surgical procedures for adverse birth outcomes and the number needed to harm. Results: We identified 6,486,280 pregnancies, in 47,628 of which non-obstetric surgery was carried out. In comparison with pregnancies in which surgery was not carried out, we found that non-obstetric surgery was associated with a higher risk of adverse birth outcomes, although the attributable risk was generally low. We estimated that for every 287 pregnancies in which a surgical operation was carried out there was one additional stillbirth; for every 31 operations there was one additional preterm delivery; for every 25 operations there was one additional caesarean section; for every 50 operations there was one additional long inpatient stay; and for every 39 operations there was one additional low-birthweight baby. Limitations: We have no means of disentangling the effect of the surgery from the effect of the underlying condition itself. Many spontaneous abortions will not be associated with a hospital admission and, therefore, will not be included in our analysis. A spontaneous abortion may be more likely to be reported if it occurs during the same hospital admission as the procedure, and this could account for the associated increased risk with surgery during pregnancy. There are missing values of key data items to determine parity, gestational age, birthweight and stillbirth. Conclusions: This is the first study to report the risk of adverse birth outcomes following non-obstetric surgery during pregnancy across NHS hospitals in England. We have no means of disentangling the effect of the surgery from the effect of the underlying condition itself. Our observational study can never attribute a causal relationship between surgery and adverse birth outcomes, and we were unable to determine the risk of not undergoing surgery where surgery was clinically indicated. We have...

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