INTRODUCTION
Nonobstetric surgery during pregnancy is performed in 0.7%−2% of patients. Most common procedures are abdominal (26%), dental (11%), nail and skin-related (10%) and orthopaedic (10%) surgery. Most often, surgeries unrelated to pregnancy are performed due to urgent surgical illness or trauma, and elective surgery is commonly postponed until after delivery. Most of the publications on nonobstetric surgery during pregnancy are focused on specific operations, for example, appendectomy or comparisons of surgical techniques, for example, open versus laparoscopic. Overall, less is known about entire surgical procedures during pregnancy as well as pregnancy and foetal outcome.
A recent guideline published by the American College of Obstetricians and Gynaecologists' Committee proposes that a pregnant woman should not be denied treatment for surgical disease considered medically necessary if a delayed surgery can adversely affect the health of the pregnant woman and her foetus. The Current Care guideline in Finland about patient preoperative evaluation for elective surgery was first published in 2008 and the first revision in 2014. In this guideline, elective surgery during pregnancy was recommended to be postponed after delivery or performed after organogenesis, if possible. The Finnish guideline also highlights that acute surgical diseases must be operated on during pregnancy to prevent maternal morbidity, foetal miscarriage or foetal wastage. However, data on compliance with these guidelines are sparse. In general, adherence to guidelines can be inconsistent despite the perceived importance of the guideline.
The aim of the present study was to assess how much and on which specialities nonobstetric surgery was performed for pregnant women in Finland during a 21-year period, between 1997 and 2017. Our specific interest was to evaluate the effect of the Current Care guideline and the first revision on physician behaviour. To evaluate this, the number of performed nonobstetric surgeries during pregnancy was searched from healthcare registers for three different time periods: before the guideline (1997−2008), time after the guideline (2009−2013) and after the first revision (2014−2017) with special reference on elective and emergency surgery. Our hypothesis was that after the first guideline and the first revision, the proportion of pregnant women undergoing elective nonobstetric surgery decreased compared to that before the guideline.
METHODS
This study is based on data gathered from the Finnish Medical Birth Register (MBR). This database contains data on sociodemographic factors, pregnancy and delivery characteristics and diagnoses on all live births or stillbirths delivered after the 22nd gestational week or weighing 500 g or more until the end of the early neonatal period since 1987 in Finland. A record linkage was applied, combining the MBR data with information on primary and secondary diagnoses by ICD-10 (International Statistical Classification of Diseases and Related Problems) and surgical procedures by NSCP (NOMESCO Classification of Surgical Procedures) available in the Hospital Discharge Register (HDR). These registers are maintained and authorised for use by the Finnish Institute for Health and Welfare, Finland (reference number THL/1015/5.05.00/2019/11.11.2019). In addition, data on major congenital anomalies, which include structural anomalies, chromosomal and congenital hypothyroidism, were gathered from The Register of Congenital Malformations by the Finnish Institute for Health and Welfare and linked with the data from MBR and HDR. The data linkages were done by using the mother's and newborn's pseudonymised ID numbers. Since the data were pseudonymised and no registered person was contacted, neither informed consent nor an ethical committee statement was required.
The primary outcome measures were the prevalence of nonobstetric surgery, proportions of elective and emergency surgery and proportion of nonobstetric surgery performed during the three trimesters. Secondary outcome measures were pregnancy outcomes, major anomalies and maternal or pregnancy-related deaths related to childbirth.
Data concerning all singleton births were collected for 21 years between 1997 and 2017 (n = 1 175 677) and covered all women who had undergone nonobstetric surgical procedures during pregnancy (according to HDR) and given birth (according to MBR). The 21-year study period was analysed in three time periods: first 12-year period, years 1997−2008 before the Current Care guideline was published; second 5-year period, years 2009−2013 after the Current Guideline had been published; and the third 4-year period, years 2014−2017 after the first revision of the Guideline had been published. For these three periods prevalence of emergency and elective nonobstetric surgery during gestation was compared. Surgical operations were classified, and amounts were calculated according to ICD-10/NSCP codes for different surgical specialties. Some patients may have had several procedures during surgery, but this entity was counted as a single surgical procedure. Furthermore, the distribution of surgical procedures by trimester was quantified.
Timing of surgery related to gestational age (the first, second or third trimester) and pregnancy outcome (stillbirth from 22 weeks of gestation or preterm birth below 37 weeks of gestation) and maternal or pregnancy-related deaths were evaluated in women who underwent nonobstetric surgery during gestation. Maternal death is defined as death while pregnant or within 42 days of the end of pregnancy, from any cause related to or aggravated by the pregnancy or its management, but not from accidental or incidental causes. A pregnancy-related death is defined as death while pregnant or within 1 year of the end of pregnancy, from any cause. These data on the pregnancy outcomes of women undergoing nonobstetric surgery during pregnancy were compared to women who had no surgery during gestation over the three time periods (years 1997−2008, 2009−2013 and 2014−2017).
Statistical analyses
Differences between the groups, women undergoing nonobstetric surgery during pregnancy and women without nonobstetric surgery during pregnancy, were evaluated by χ2 test for dichotomous and categorical variables and Student's t test for continuous variables. Rates with 95% confidence intervals (CI) were calculated. Differences were deemed to be significant if p value was less than 0.05. The data were analysed using SAS 9.4 (SAS Institute Inc.) and IBM SPSS Statistics 26.0 (IBM).
RESULTS
Characteristics of pregnant women with and without nonobstetric surgery between 1997 and 2017 are listed in Table .
Table 1 Baseline characteristics of pregnant women with or without nonobstetric surgery during 1997−2017
Pregnant women with nonobstetric surgery | Pregnant women with no nonobstetric surgery | |||
First trimester | Second trimester | Third trimester | ||
Years 1997−2008 | ||||
Number of pregnant women; N = 671 145 | 990 (0.15%) | 970 (0.14%) | 680 (0.10%) | 668 505 (99.6%) |
Age (years) | 30.9 (5.8) | 30.2 (5.7) | 30.5 (6.0) | 29.9 (5.4) |
Parity | 1.0 (1.5) | 0.8 (1.2) | 0.9 (1.3) | 1.1 (1.4) |
BMI (kg/m2) | 25.0 (5.1) | 24.5 (4.8) | 25.1 (5.8) | 24.2 (4.8) |
Years 2009−2013 | ||||
Number of pregnant women; N = 292 321 | 270 (0.09%) | 290 (0.10%) | 263 (0.09%) | 291 498 (99.7%) |
Age (years) | 29.2 (5.8) | 30.2 (5.8) | 30.4 (5.8) | 30.2 (5.3) |
Parity | 0.6 (1.3) | 0.6 (0.9) | 0.6 (1.1) | 1.0 (1.4) |
BMI (kg/m2) | 25.0 (5.2) | 25.1 (5.2) | 25.0 (5.8) | 24.4 (4.9) |
Years 2014−2017 | ||||
Number of pregnant women; N = 212 211 | 266 (0.13%) | 264 (0.12%) | 298 (0.14%) | 211 383 (99.6%) |
Age (years) | 29.1 (6.0) | 30.3 (5.7) | 29.8 (5.9) | 30.6 (5.3) |
Parity | 0.7 (1.3) | 0.7 (1.3) | 0.6 (1.0) | 1.1 (1.4) |
BMI (kg/m2) | 25.2 (5.1) | 25.5 (5.7) | 25.6 (5.8) | 24.6 (5.0) |
Total; N = 1 175 677 | 1526 (0.13%) | 1524 (0.13%) | 1241 (0.11%) | 1 171 386 (99.6%) |
Median of the annual number of deliveries was 56 209/year (range: 54 043–57 981) during the first 12-year period between 1997 and 2008, increased to 58 398/year (56 692–59 284) between 2009 and 2013, and decreased to 52 819/year (49 066–55 825) during the last period between 2014 and 2017.
Primary outcomes
There was a significant difference in the prevalence of nonobstetric surgery between the three time periods (p < 0.001). During the first 12-year period before the Current Care guideline was published, 0.39% (2640 of 671 145; 95% confidence intervals (CI) 0.38%, 0.41%) pregnant women underwent nonobstetric surgery, during the 5-year period after the Current Care guideline was published 0.28% (823 of 292 321; 95% CI 0.26%, 0.30%) women, and during the last 4-year period after the first revision of the guideline was published 0.39% (828 of 212 211; 95% CI 0.36%, 0.42%) pregnant women received nonobstetric surgery. The proportion of women undergoing nonobstetric surgery decreased from the first period to the second (p < 0.001) but returned to a similar proportion than before the publication of the Current Care guideline during the first 4 years after the revision (p = 0.838) (Table ).
The increase of surgery prevalence after the first revision to similar of that before the Current Care guideline was based on the increase on emergency surgery after the first revision. Volume of elective nonobstetric surgery decreased after the Current Care guideline was published and remained at this lower level after the first revision. Before the Current Care guideline, 0.16%, n = 1054 (157/100 000; 95% CI 0.15%, 0.17%) pregnant women underwent elective nonobstetric surgery, and thereafter the volume decreased to 0.07%, n = 207 (71/100 000; 95% CI 0.06%, 0.08%) in 2009−2014 and was similarly low after the first revision, 0.10%, n = 204, (96/100 000; 95% CI 0.08%, 0.11%) (p < 0.001) (Figure ). On the contrary to elective surgery, the prevalence of emergency surgery first decreased from 0.24%, n = 1580 (263/100 000; 95% CI 0.22%, 0.25%) to 0.21%, n = 616 (210/100 000; 95% CI 0.19%, 0.23%) during the two first study periods, but then increased to 0.29%, n = 624 (294/10 000; 95% CI 0.27%, 0.32%) pregnant women with emergency nonobstetric surgery after the first revision of the guideline (p < 0.001) (Figure ).
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Before the guideline, 37% of all surgeries were performed during the first trimester, 37% during the second trimester and 26% during the third trimester. After the guideline (33%, 35% and 32%) and after the first revision (32%, 32% and 36%), the distribution was more equal between the trimesters (p = 0.003).
The guideline and the first revision did not affect the proportion of elective nonobstetric surgery performed during the second trimester; before the guideline, 35% of elective surgeries were performed during the second trimester, compared to 36% after the guideline and the first revision. However, the guideline and the revision had a significant impact on the proportions of elective and emergency surgeries between the trimesters. Before the guideline, 51% of the surgeries in the first trimester were elective cases, 38% in the second trimester and 27% in the third trimester. The proportions of elective surgeries were significantly lower after the guideline (31%, 26% and 19%) and after the first revision (27%, 28% and 19%) in the three trimesters, respectively (p < 0.001).
Different surgical specialities
The proportion of gastrointestinal procedures was highest; these procedures comprised 44%−47% of all nonobstetric surgeries during the three time periods (Table ). The volume of gastrointestinal surgery was 58/100 000 pregnant women in the first trimester, the highest, 65/100 000 in the second trimester and the lowest, 41/100 000 pregnant women in the third trimester (p < 0.001). In gastroenterological surgery, the proportion of elective surgery decreased significantly after the Current Care Guideline publication, 15% of surgeries were elective before the Current Care Guideline and 10% thereafter (p = 0.004). Three operation types from gastrointestinal surgical speciality were included among the eight most common operations, that is, cholecystectomy, appendectomy and incision of the perianal abscess (Table ).
Table 2 Type of nonobstetric surgery performed on pregnant women during years 1997−2008 (N = 671 145) before publication of the Current Care Guideline, years 2009−2013 (N = 292 321) after the publishing of the Current Care Guideline and years 2014−2017 (N = 212 211) after the first revision of the Current Care Guideline
Pregnant women with nonobstetric surgery | |||||
First trimester | Second trimester | Third trimester | Total | p Value between time periods/proportion of elective cases | |
Gastrointestinal surgery: total number of cases (elective cases %) | |||||
Years 1997−2008 | 419 (27%) | 452 (9%) | 286 (9%) | 1157 (15%) | |
Years 2009−2013 | 126 (15%) | 157 (8%) | 100 (7%) | 383 (10%) | <0.001/0.004 |
Years 2014−2017 | 140 (11%) | 133 (9%) | 91 (11%) | 364 (10%) | |
Gynaecologic surgery: total number of cases (% of elective cases) | |||||
Years 1997−2008 | 148 (50%) | 180 (78%) | 87 (30%) | 415 (58%) | |
Years 2009−2013 | 34 (32%) | 46 (50%) | 44 (27%) | 124 (37%) | <0.001/<0.001 |
Years 2014−2017 | 38 (32%) | 50 (52%) | 65 (25%) | 153 (36%) | |
Orthopaedic surgery: total number of cases (% of elective cases) | |||||
Years 1997-2008 | 188 (64%) | 116 (53%) | 90 (29%) | 390 (53%) | |
Years 2009-2013 | 40 (48%) | 32 (38%) | 29 (21%) | 101 (37%) | <0.001/<0.001 |
Years 2014-2017 | 34 (26%) | 13 (46%) | 20 (15%) | 67 (27%) | |
Urologic surgery: total number of cases (elective cases %) | |||||
Years 1997−2008 | 9 (67%) | 61 (38%) | 85 (36%) | 155 (39%) | |
Years 2009−2013 | 13 (38%) | 21 (14%) | 63 (22%) | 97 (23%) | <0.001/0.002 |
Years 2014−2017 | 5 (60%) | 24 (8%) | 70 (21%) | 99 (20%) | |
Plastic surgery: total number of cases (elective cases %) | |||||
Years 1997−2008 | 53 (77%) | 40 (68%) | 50 (62%) | 143 (69%) | |
Years 2009−2013 | 10 (60%) | 11 (73%) | 13 (46%) | 34 (59%) | 0.006/0.477 |
Years 2014−2017 | 11 (73%) | 14 (71%) | 14 (50%) | 39 (64%) | |
Ear−nose−throat surgery: total number of cases (elective cases %) | |||||
Years 1997−2008 | 108 (82%) | 36 (72%) | 20 (60%) | 165 (77%) | |
Years 2009−2013 | 20 (75%) | 4 (75%) | 5 (20%) | 29 (66%) | <0.001/<0.001 |
Years 2014−2017 | 16 (63%) | 6 (67%)0 | 14 (0%) | 36 (39%) | |
Neurosurgery: total number of cases (elective cases %) | |||||
Years 1997−2008 | 21 (76%) | 30 (30%) | 12 (33%) | 63 (46%) | |
Years 2009−2013 | 11 (18%) | 3 (33%) | 3 (0%) | 17 (18%) | 0.037/0.056 |
Years 2014−2017 | 9 (78%) | 10 (20%) | 8 (63%) | 27 (52%) | |
Eye surgery: total number of cases (elective cases %) | |||||
Years 1997−2008 | 17 (94%) | 26 (73%) | 27 (70%) | 70 (77%) | |
Years 2009−2013 | 7 (14%) | 4 (100%) | 1 (100%) | 12 (50%) | 0.002/0.028 |
Years 2014−2017 | 3 (67%) | 5 (60%) | 3 (0%) | 11 (45%) | |
Endocrinological surgery: total number of cases (elective cases %) | |||||
Years 1997−2008 | 9 (100%) | 14 (100%) | (100%) | 31 (100%) | |
Years 2009−2013 | 3 (100%) | 7 (100%) | - | 10 (100%) | 0.607/1.0 |
Years 2014−2017 | 4 (100%) | 7 (100%) | - | 11 (100%) | |
Vascular surgery: total number of cases (elective cases %) | |||||
Years 1997−2008 | 15 (93%) | 4 (75%) | 6 (17%) | 25 (72%) | |
Years 2009−2013 | - | 1 (100%) | 2 (0%) | 3 (33%) | 0.015/0.355 |
Years 2014−2017 | 2 (50%) | - | - | 2 (50%) | |
Thoracic surgery: total number of cases (elective cases %) | |||||
Years 1997-2008 | 3 (67%) | 2 (100%) | 4 (25%) | 9 (56%) | |
Years 2009-2013 | 1 (100%) | - | 1 (100%) | 2 (100%) | <0.001/0.120 |
Years 2014-2017 | 2 (50%) | 1 (100%) | 8 (13%) | 11 (27%) | |
Other surgery: total number of cases (elective cases %) | |||||
Years 1997−2008 | 4 (50%) | 9 (44%) | 5 (40%) | 18 (44%) | |
Years 2009−2013 | 5 (40%) | 4 (0%) | 2 (50%) | 11 (27%) | 0.584/0.713 |
Years 2014−2017 | 2 (50%) | 1 (0%) | 5 (20%) | 8 (25%) | |
Of these all cancer surgery: total number (elective cases %) | |||||
Years 1997−2008 | 50 (94%) | 107 (80%) | 41 (80%) | 198 (84%) | |
Years 2009−2013 | 12 (92%) | 26 (85%) | 9 (78%) | 47 (85%) | 0.001/0.975 |
Years 2014−2017 | 16 (94%) | 26 (81%) | 6 (83%) | 49 (84%) |
Table 3 Eight most common nonobstetric surgery in pregnant women during 1997−2017
Pregnant women with nonobstetric surgery | |||||
First trimester | Second trimester | Third trimester | Total (n/100 000) | p Value between time periods | |
Appendectomy, n | |||||
Years 1997−2008 | 189 | 331 | 198 | 107/100 000 | <0.001 |
Years 2009−2013 | 59 | 111 | 72 | 83/100 000 | |
Years 2014−2017 | 56 | 81 | 40 | 83/100 000 | |
Diagnostic laparoscopy, n | |||||
Years 1997−2008 | 85 | 18 | 14 | 17/100 000 | 0.002 |
Years 2009−2013 | 34 | 10 | 4 | 17/100 000 | |
Years 2014−2017 | 39 | 13 | 9 | 29/100 000 | |
Oophorectomy/Salpingo-oophorectomy, n | |||||
Years 1997−2008 | 36 | 82 | 11 | 19/100 000 | 0.159 |
Years 2009−2013 | 13 | 23 | 4 | 14/100 000 | |
Years 2014−2017 | 8 | 20 | 12 | 19/100 000 | |
Cholecystectomy, n | |||||
Years 1997−2008 | 61 | 38 | 3 | 15/100 000 | 0.325 |
Years 2009−2013 | 13 | 16 | 4 | 11/100 000 | |
Years 2014−2017 | 13 | 11 | 7 | 15/100 000 | |
Internal fixation of fracture of the ankle, n | |||||
Years 1997−2008 | 14 | 17 | 30 | 9/100 000 | 0.410 |
Years 2009−2013 | 2 | 5 | 16 | 8/100 000 | |
Years 2014−2017 | 4 | 1 | 8 | 6/100 000 | |
Tonsillectomy, n | |||||
Years 1997−2008 | 32 | 1 | - | 5/100 000 | 0.029 |
Years 2009−2013 | 7 | - | - | 2/100 000 | |
Years 2014−2017 | 2 | - | 1 | 1/100 000 | |
Bartholin gland marsupialisation, n | |||||
Years 1997-2008 | 5 | 2 | 15 | 3/100 000 | 0.436 |
Years 2009-2013 | 2 | 5 | 3 | 3/100 000 | |
Years 2014-2017 | 5 | 1 | 5 | 5/100 000 | |
Anal or perianal incision with/without drainage or biopsy | |||||
Years 1997−2008 | 3 | 8 | 7 | 3/100 000 | 0.005 |
Years 2009−2013 | 1 | 4 | 4 | 3/100 000 | |
Years 2014−2017 | 4 | 4 | 8 | 8/100 000 |
The second most common procedures were nonobstetric gynaecological surgeries, 15%−18% of all surgeries during pregnancy. In gynaecological surgery, the proportion of elective procedures decreases from 58% before the guideline, to 37% and 35% after the publication of the guideline and the first revision, respectively (p < 0.001). However, the volume of gynaecological surgery first decreased from 62/100 000 pregnant women to 42/100 000 women after the guideline but then increased to 72/100 000 pregnant women during the last 4-year time period, respectively (p < 0.001) (Table ).
The most substantial impact the Current Care guideline in 2008 and the first revision in 2014 had on elective orthopaedic surgery. Before the Guideline was published, 31/100 000 pregnant women had elective orthopaedic surgery, after the guideline publication 13/100 000 and after the revision 8/100 000 (p < 0.001). The need for emergency orthopaedic surgery remained rather similar, 27/100 000 in the first period and 20/100 000 in the two later periods (p = 0.046). The volume of all orthopaedic surgery was highest in the first trimester, 22/100 000 pregnant women, and similar in the second, 14/100 000 and third trimester, 12/100 000 pregnant women, respectively (p < 0.001) (Table ).
The proportion of other surgical specialities was low, 6% of nonobstetric surgeries were urological procedures in the first period and 12% in the two other periods. The numbers of elective surgery were similarly low, between 7/100 000 and 9/100 000 pregnant women in three time periods, respectively. The proportion of plastic surgery was 4%−5% of all procedures and that of ear, nose and throat (ENT) surgery was 6% before the Current Care guideline, and 3% and 4% thereafter. The number of elective surgeries decreased significantly in both specialities; in plastic surgery from 15 procedures/100 000 pregnant women and in ENT surgery from 18 procedures/100 000 pregnant women to 6 procedures/100 000 pregnant women in both specialities after the Current Care guideline and the first revision publication (Table ).
Surprisingly, the volume of cancer-related surgery varied significantly between the three time periods; from 1997 to 2008, cancer-related surgery was performed on 30/100 000 pregnant women, from 2009 to 2013 on 16/100 000 pregnant women and on 23/100 000 pregnant women during 2014−2017 (p = 0.001) (Table ).
The eight most common surgical procedures are listed in Table . Appendectomy was the most common procedure in all three time periods. The proportion of laparoscopic appendectomies increased significantly (p < 0.001); during the first 12-year period, 6% of the cases were laparoscopic, during the years 2009−2013, it was 26% and in 2014−2017 it was 49%. The laparoscopic approach was used most commonly during the first (13%, 54% and 73% in the three time periods) and the second trimester (5%, 27% and 52%), and less frequently in the third trimester (1%, 1% and 8%). Most of the cholecystectomies, the fourth most common procedure, were performed laparoscopically and the proportion of the laparoscopic approach increased from 71% to 84% during the second time period and was 90% during the most recent years (p = 0.036). In cholecystectomies, laparoscopic technique was common in all trimesters (89%, 65% and 71%, p = 0.001).
Pregnancy outcomes
The proportion of preterm deliveries was higher among pregnancies with surgery, 9.1%−9.4% of pregnancies with nonobstetric surgery ended with preterm delivery compared to 4.5%−4.6% (p < 0.001 in all three time periods) of pregnancies without nonobstetric surgery. During which trimester the surgery was performed did not affect the proportion of preterm deliveries (Table ). Nonobstetric surgery did not affect the risk of stillbirth (Table ).
Table 4 Pregnancy outcome before (years 1997−2008, N = 671 145) and after the Current Care guideline introduction (years 2009−2014, N = 292 321), and after the first revision (years 2014−2017, N = 212 211)
Pregnant women with nonobstetric surgery | Pregnant women with no nonobstetric surgery | p Value between time periods/trimesters/surgery versus no surgery | |||
First trimester | Second trimester | Third trimester | |||
Delivery at term | |||||
Years 1997−2008 | 910 (91.9%) | 874 (90.1%) | 615 (90.4%) | 637 686 (95.4%) | |
Years 2009−2013 | 247 (91.5%) | 260 (89.7%) | 239 (90.9%) | 278 502 (95.5%) | |
Years 2014−2017 | 250 (94.0%) | 237 (89.8%) | 265 (88.9%) | 201 600 (95.4%) | |
Preterm delivery | |||||
Years 1997−2008 | 80 (8.1%) | 96 (9.9%) | 65 (9.6%) | 30 819 (4.6%) | 0.981 |
Years 2009−2013 | 23 (8.5%) | 30 (10.3%) | 24 (9.1%) | 12 996 (4.5%) | <0.001 |
Years 2014−2017 | 16 (6.0%) | 27 (10.2%) | 33 (11.1%) | 9783 (4.6%) | <0.001 |
Stillbirth | |||||
Years 1997−2008 | 3 (0.30%) | 5 (0.52%) | 1 (0.15%) | 2252 (0.34%) | 0.993 |
Years 2009−2013 | 2 (0.74%) | 1 (0.34%) | - | 782 (0.27%) | 0.163 |
Years 2014−2017 | 2 (0.75%) | 1 (0.38%) | - | 585 (0.28%) | 0.632 |
Major anomaly | |||||
Years 1997−2008 | 47 (4.7%) | 27 (2.8%) | 27 (4.0%) | 23 876 (3.6%) | <0.001 |
Years 2009−2013 | 17 (6.3%) | 12 (4.1%) | 23 (8.7%) | 13 734 (4.7%) | 0.045 |
Years 2014−2017 | 12 (4.5%) | 18 (6.8%) | 21 (7.0%) | 10 940 (5.2%) | 0.046 |
Maternal deaths | |||||
Years 1997−2008 | - | - | 1 (147/100,000) | 26 (4/100 000) | - |
Years 2009−2013 | - | - | - | 7 (2/100 000) | - |
Years 2014−2017 | - | - | 6 (3/100 000) | 0.025 | |
Pregnancy-related deaths | |||||
Years 1997−2008 | 1 (101/100 000) | 2 (206/100 000) | 6 (882/100 000) | 120 (18/100 000) | 0.158 |
Years 2009−2013 | - | 1 (345/100 000) | - | 35 (12/100 000) | 0.072 |
Years 2014−2017 | - | - | - | 25 (12/100 000) | <0.001 |
There were 40 maternal deaths during the 21-year study period, the median of annual mortality rate was 3.4 per 100 000 live births; in 2004, seven mothers died and in 2011, there were no cases of maternal deaths during the pregnancy or within 42 days of termination of pregnancy. The maternal mortality rate was similarly low during the three periods; 3.9/100 000 childbirths during the first period, 2.4/100 000 pregnant women during the second period and 2.8/100 000 pregnant women during the third period (p = 0.068). During the first 12-year period before the guideline, one woman died after obstetric surgery, the removal of cerclage of cervix uteri. She had an immediate postpartum haemorrhage that was considered unrelated to the surgical procedure. No deaths were associated with nonobstetric surgery during the 21-year study period.
During the first period, years 1997−2008 pregnancy-related deaths, parturient who died within 1 year after the pregnancy ended from any cause, were more common in women having nonobstetric surgery, 341/100 000 childbirths, than in women with no nonobstetric surgery, 18/100 000 childbirths (p < 0.001). In women without nonobstetric surgery, the pregnancy-related mortality rate decreased to 12/100 000 childbirths during the two later time periods (p = 0.034) (Table ).
There was no significant difference in major congenital anomaly rate in infants after pregnancies with nonobstetric surgery and infants after pregnancies without surgery, 4.8% versus 4.1%. The rate of anomalies was lowest, 3.7% if the surgery was performed during the second trimester compared to 5.0% after surgery during the first trimester and 5.7% after surgery during the third trimester (p = 0.045). The major anomaly rate increased after the guideline and the first revision both in infants after pregnancy with surgery (p = 0.001) and no surgery (p < 0.001) (Table ).
DISCUSSION
The first Current Care guideline in Finland about preoperative evaluation for elective surgery was published in 2008 and revised in 2014. During the preoperative evaluation, elective surgery during pregnancy was instructed to be postponed after the delivery or delayed to time after the major organogenesis period, to gestational weeks between 12 and 28, that is, the late first or the second trimester. Necessary and emergency surgery was advised to be performed at the most suitable time despite pregnancy.
The prevalence of nonobstetric surgery during pregnancy in Finland varied between 0.28% and 0.39%, the prevalence decreased after the guideline but returned later back to that before the guideline. The prevalence of nonobstetric surgery is substantially lower in Finland than reported in other countries. In the United Kingdom, 0.7% of pregnant women received nonobstetric surgery and in Denmark, the prevalence is even higher, 1.5%−1.6%, respectively. The prevalence in Finland has remained quite stable during the 21-year period as was also in Denmark. The reason for the lower prevalence of nonobstetric surgery during pregnancy in Finland remains unknown; some suggestions such as like differences in socioeconomic factors or general morbidity may influence this difference. Also, differences in prenatal maternity care may be one of the reasons for this controversy.
The Current Care guideline had a significant impact on elective surgery in Finland. Before the guideline, 40% of nonobstetric surgery in pregnant women were elective procedures, but after the guideline and after the first revision, the proportion of elective surgeries decreased to 25%. In other words, a similar prevalence of nonobstetric surgery before the guideline and after the first revision is based on the increase in emergency surgery.
Before the guideline, elective surgery was performed especially during the first trimester, but after the guideline and the first revision, the distribution was quite even between the trimesters. Similar findings have been reported from a single Australian centre. In a study by Choi et al. during 2009–2018, a total of 108 cases of nonobstetric surgery in pregnant women were performed, of which 45% were during the first trimester. Possibly patient's unawareness of pregnancy onset may have influenced a relatively high proportion of surgeries performed during the first trimester. In the present study, the risk for preterm delivery was twotimes higher in women with nonobstetric surgery (9.2%) than in women with no surgery during the surgery (4.6%). In the UK study, nonobstetric surgery during the third trimester increased the risk for preterm delivery. Similar trend was seen in the present study but not in the Australian study.
Some studies have evaluated the optimal timing of elective surgery during pregnancy. One of the most common indications for surgery during pregnancy is the occurrence of asymptomatic ovarian tumours or cysts; in the present study, ovarian surgery was the third most common surgical indication. Ovarian surgery is usually performed electively in the second trimester. These cysts are typically found at prenatal ultrasound check-ups and operated on if symptoms occur or tumour grows; sometimes, morphology in imaging studies or doctor's and patient's attitudes also encourage surgery. In a recent meta-analysis of ovarian masses operated during pregnancy, the odds ratio (OR) for postoperative spontaneous abortion was similar after elective or emergency surgery (OR 0.26; 95% CI 0.06, 1.02), but OR for preterm delivery was lower (OR 0.13; 95% CI 0.04, 0.48) after elective ovarian surgery than after emergency surgery. This highlights appropriate preoperative evaluation when any surgical interventions are planned in pregnant women.
Although appendectomies and tonsillectomies decreased significantly during the three different time periods in the present study, the prevalence of diagnostic laparoscopies decreased from the first time period to the second but returned to a similar prevalence than in the first time period. Appendectomies performed either with open or laparoscopic technique during pregnancy present similar labour outcomes to studies published after 2010. Foetal loss was more common in studies performed before 2010. The reason would be more developed surgical techniques after 2010. However, when choosing a surgical technique, the gestational stage may affect surgeons' choice. During the first and second trimesters, 45%−67% of patients were operated on using the laparoscopic technique and in the third trimester, only 19% were operated on laparoscopically. Similar trend was noted in the present study as diagnostic laparoscopies were performed more in the first two trimesters.
According to a literature review by Cohen-Kerem et al., more surgery-induced labours were reported after appendectomy compared to other surgical procedures (73/1559 vs. 6/723, 4.6% vs. overall 3.5%). Appendicitis with perforation and peritonitis was associated with foetal loss in 10.9% of cases, supporting early and accurate diagnostics and treatment thereafter. The foetal loss rate for appendectomy without peritonitis was 2.6% (40/1559) versus 1.2% (56/4485) for other surgical procedures during pregnancy. Conservative treatment of appendicitis was associated with similar rates of foetal loss compared to operative treatment (4% vs. 5% after operative, open or laparoscopic treatment in a study by Nakashima et al.). There were no maternal deaths or serious complications after any treatment. The proportion of complicated appendicitis was 6% in conservative management and 41% in appendectomy. In five patients having foetal loss after conservative treatment of appendicitis, the disease was successfully treated, and no recurrence of appendicitis was observed before foetal losses. A 4% rate of foetal loss and a 5% rate of early delivery was reported after negative appendicitis (a noninfectious finding in surgery) in the study by McGory et al.
There are no means of disentangling the effect of the surgery from the effect of the underlying condition itself. Therefore, surgical disease, anaesthesia and surgery itself may have an effect on labour outcome and cannot be separated. Preterm delivery occurred similarly after nonobstetric surgery in the United Kingdom at 11% and in the present study at 8%−10%. A recent large systematic review and meta-analysis by Cusimano et al. presented similar results for preterm delivery after abdominopelvic surgery. The proportion of stillbirths was higher in the United Kingdom, 0.9% and 0.35% in the present study. Although in the Balinskaite and colleagues' study, multiple pregnancies were included and in the present study only singleton pregnancies, the pregnancy outcomes are quite similar. It seems that despite differences in maternity care systems in Finland and the United Kingdom, both provide quality care.
Maternal mortality in Finland is generally low and no deaths were reported to be associated with nonobstetric surgery. In a large cohort study in the United Kingdom 0.025% of maternal deaths were included if they occurred at the same hospital stay as miscarriage or delivery. Pregnancy-related death within a year of delivery was significantly more common in women who had nonobstetric, elective or emergency surgery during pregnancy than in women without. The reason for this is unclear and warrants further evaluation.
In conclusion, the overall prevalence of nonobstetric surgery during pregnancy is low in Finland, and after the publication of the Current Care Guideline about preoperative evaluation, the number of performed elective and emergency surgery decreased. After nonobstetric surgery during pregnancy, preterm delivery was more common than without surgery.
AUTHOR CONTRIBUTIONS
All authors have contributed to the conception and planning, data collection, formal analysis, writing of the original draft, review and editing, supervision and resources of this study.
ACKNOWLEDGEMENT
The present study had no external funding.
CONFLICT OF INTEREST
The authors declare no conflict of interest.
DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available from the Finnish Institute of Health and Welfare, Helsinki, Finland. Restrictions apply to the availability of these data, which were used under licence for this study. Data are available with the permission of The Finnish Institute of Health and Welfare, Helsinki, Finland.
ETHICS STATEMENT
The Finnish Institute for Health and Welfare, Finland, authorised the use of the data with permission (reference number THL/1015/5.05.00/2019/11.11.2019). The data were pseudonymised and no registered person was contacted, neither informed consent nor an ethical committee statement was required.
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Abstract
Objective
To assess how much and on which specialities nonobstetric surgery was performed for pregnant women in Finland during a 21‐year period, between 1997 and 2017 and the effect of Finnish guideline about preoperative evaluation affected the amount of surgery during pregnancy.
Design
Register‐based observational study.
Setting
Finnish Medical Birth Register.
Population
1 175 677 pregnancies ending with a singleton birth 1997−2017.
Methods
Amount of nonobstetric surgeries, and pregnancy foetal and maternal outcomes in Finland between 1997 and 2017 were searched.
Main Outcome Measures
The prevalence of nonobstetric surgery, and proportions of elective and emergency nonobstetric surgery performed during the three trimesters.
Results
The prevalence of nonobstetric surgery before the guideline was 0.39%, after the guideline 0.28% and after the first revision 0.39%. The prevalence of elective surgery decreased after the guideline (before 0.15%, after the guideline 0.10% and 0.07% after the first revision), but the prevalence of emergency surgery was highest after the first revision (0.24%, 0.21% and 0.29%). The guideline and the first revision had no impact on the timing of elective surgery; 35% of elective surgery was performed during the second trimester before the guideline, 36% after it and 36% after its first revision. The preterm delivery rate, 9.1%−9.4% of pregnancies with nonobstetric surgery was twofold higher than that of pregnancies without surgery.
Conclusion
The prevalence of nonobstetric surgery during pregnancy is low in Finland. The national guideline decreases the prevalence of elective surgery during pregnancy but does not impact the timing of nonobstetric surgery.
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Details




1 Faculty of Medicine, University of Oulu, Oulu, Finland
2 Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
3 Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
4 Information Services Department, Finnish Institute of Health and Welfare, Helsinki, Finland
5 Department of Paediatric Surgery, Kuopio University Hospital, Kuopio, Finland
6 Department of Anaesthesiology and Intensive Care, Kuopio University Hospital, Kuopio, Finland