Abstract
Introduction
Alcohol consumption during pregnancy is related to severe birth complications such as low birthweight, preterm birth and birth defects. During the last decade, the Alcohol Use Disorders Identification Test (AUDIT) has been used as a screening tool in Swedish maternal healthcare units to identify hazardous, pre‐pregnancy alcohol use. However, evaluation of the screening with AUDIT, as well as adverse maternal or neonatal outcomes, has not been assessed at a national level.
Material and methods
This was a population‐based cohort study of 530 458 births from 2013 to 2018 using demographic, reproductive and maternal health data from the Swedish Pregnancy Register. Self‐reported alcohol consumption in the year before pregnancy, measured as AUDIT scores, was categorized into moderate (6–13 points) and high‐risk (14–40 points) consumption, with low‐risk (0–5 points) consumption as the reference group. Associations with pregnancy‐ and birth outcomes were explored with logistic regressions using generalized estimating equation models, adjusting for maternal and socioeconomic characteristics. Estimates are presented as adjusted odds ratios (aORs) with 95% confidence intervals (CIs).
Results
High‐risk and moderate pre‐pregnancy alcohol consumption was associated with preeclampsia, preterm birth and birth of an infant small for gestational age (SGA), but these associations were nonsignificant after adjustments. Prior moderate‐risk (aOR 1.29, 95% CI 1.17–1.42) and high‐risk consumption (aOR 1.62, 95% CI 1.17–2.25) increased the likelihood of intrapartum and neonatal infections.
Conclusions
Apart from identifying hazardous alcohol consumption prior to pregnancy and the offer of counseling, screening with the AUDIT in early pregnancy indicates a high risk of inflammatory‐/placenta‐mediated pregnancy and birth outcomes. For most outcomes, AUDIT was not an independent contributor when adjusting for confounding factors. Hazardous alcohol use prior to pregnancy was independently linked to intrapartum and neonatal infections; conditions associated with morbidity and long‐term sequalae. These associations may be explained by alcohol‐induced changes in the maternal or fetal immune system in early pregnancy or persistent alcohol intake during pregnancy, or may depend on unidentified confounding factors.
Keywords: alcohol drinking, placentation, pregnancy, prenatal care, preterm birth
Hazardous alcohol consumption before pregnancy, as based upon AUDIT before pregnancy, is linked to a higher risk for intrapartum and neonatal infections. AUDIT could serve as a screening tool for a wide range of adverse pregnancy outcomes.
Abbreviations
- ANOVA
analysis of variance
- aOR
adjusted odds ratio
- AUDIT
Alcohol Use Disorders Identification Test
- CI
confidence interval
- OR
odds ratio
- SPR
Swedish Pregnancy Register
Key message.
Hazardous alcohol consumption before pregnancy, as based on the Alcohol Use Disorders Identification Test (AUDIT), is linked to a higher risk for intrapartum and neonatal infections. Therefore, AUDIT could serve as a screening tool for a wide range of adverse pregnancy outcomes.
1. INTRODUCTION
For almost half a century, alcohol has been recognized as a teratogenic substance and its use during pregnancy increases the risk for adverse perinatal outcomes, such as fetal alcohol syndrome.1 Heavy alcohol consumption during pregnancy has been associated with spontaneous abortion, low birthweight, preterm birth, birth defects and stillbirth.2 A dose–response relation has been observed,3, 4 but no lower threshold/safe period has been established for alcohol use. The recommendation from the World Health Organization and Swedish guidelines urge total abstinence from alcohol during pregnancy.2, 5 Furthermore, it is urged to identify women with alcohol consumption early in pregnancy, so that counseling and treatment can be offered.2
Low to moderate alcohol consumption has anti‐inflammatory effects, whereas high alcohol consumption is associated with elevated inflammatory marker levels and a suppressed immune system in non‐pregnant subjects.6 In experimental studies, alcohol impacts placental morphology, leading to apoptosis of trophoblast cells. It also increases expression of oxidative stress markers and proinflammatory cytokines in the placenta.7, 8 Higher levels of cytokines have been observed in infants with fetal alcohol syndrome and their mothers,9, 10 potentially leading to an increased risk for severe infections in such infants.11, 12 An increased inflammatory response and impaired placentation can lead to a wide range of adverse outcomes including spontaneous abortion, preeclampsia, placental abruption, intrauterine growth restriction and preterm birth.13 Moreover, pregnancy induces a major maternal immune system modulation and failures in this modulation are associated with a risk of adverse pregnancy outcomes.14 Studies on the effect of alcohol prior to pregnancy are scarce. However, a study of ethanol consumption before conception in mice demonstrated an increased risk of abnormal fetal development, including growth retardation,15 indicating that alcohol intake before pregnancy could influence birth outcomes.
Since 2012, maternity healthcare providers in Sweden have been recommended to use the Alcohol Use Disorders Identification Test (AUDIT) as a screening tool to identify hazardous/harmful alcohol consumption before and during pregnancy.16, 17 The AUDIT questionnaire is completed by a midwife who interviews the pregnant woman at the first antenatal care visit regarding alcohol consumption for the year prior to pregnancy. A score of six points or more is considered hazardous consumption and women will be recommended for an individual antenatal care program and/or medical assessment by a physician.2
There is a gap of knowledge regarding how consumption of alcohol prior to pregnancy affects the risk of adverse maternal and neonatal outcomes. Therefore, the aim of this study was to investigate whether hazardous alcohol consumption before pregnancy, based on AUDIT scores, was linked to placenta‐ and inflammatory‐mediated pregnancy outcomes in a large population‐based birth cohort. Another aim was evaluation of how well AUDIT served as a screening tool in identifying women at risk for adverse pregnancy and birth outcomes.
2. MATERIAL AND METHODS
2.1. Study population
This was a Swedish population register‐based cohort study of births in 2013–2018 using demographic, reproductive and maternal health data from the Swedish Pregnancy Register (SPR). The SPR prospectively collects data on pregnancy and childbirth, from the first antenatal care visit in the first trimester to 8–16 weeks postpartum. Information in the register is collected from manually entered data by the midwife in antenatal care, and from electronic birth records, with predefined check boxes and diagnosis codes from the International Classification of Diseases (ICD‐10).18, 19 In 2018, SPR covered more than 98% of births for the included regions, resulting in a coverage of more than 91% of all births in Sweden.
For the purpose of this study, singleton births from 22 weeks of gestation were identified in the SPR (n=530 458) and analyzed based on AUDIT scores, pregnancy and birth outcomes. In all, 104 349 women had more than one delivery during the study period, which was accounted for in analysis. Maternal characteristics included body mass index and smoking habits registered at the first antenatal visit, country of birth, and maternal age at delivery. Categorizations are shown in Table1. Socioeconomic factors included: attained education (≤9, 9–12 and >12 years), occupation (defined as employed, unemployed/on disability benefits, on parental leave, student, or other), and living condition (defined as cohabitant, one‐person household, or other family situation). Pregnancy characteristics included parity (0, 1–3 or ≥4), pre‐gestational medical conditions including hypertension, diabetes and ongoing or previous psychiatric disorders, recorded using check boxes (yes/no). For a small proportion of women, antenatal information was missing from the SPR. This could be due to the midwife not asking, not registering the information correctly, the woman not wanting to answer the question or the information not being retained in the register because the woman gave birth outside the region where she attended antenatal care.
TABLE 1.
Background characteristics of births 2013–2018 by AUDIT scores registered at first antenatal visit
No. of births=530 458 | % | AUDIT score 0–5 n=391 440 | % | AUDIT score 6–13 n=16 764 | % | AUDIT score ≥ 14 n=1142 | % | No AUDIT score n=121 112 | % | P‐value | |
---|---|---|---|---|---|---|---|---|---|---|---|
73.8 | 3.2 | 0.2 | 22.8 | ||||||||
Age (years), mean ± SD | 30.95 ± 5.14 | <0.01 | |||||||||
<20 | 5859 | 1.1 | 3928 | 1.0 | 286 | 1.7 | 65 | 5.7 | 1580 | 1.3 | |
20–34 | 406 370 | 76.6 | 299 087 | 76.4 | 14 172 | 84.5 | 939 | 82.2 | 92 172 | 76.1 | |
≥35 | 118 072 | 22.3 | 88 341 | 22.6 | 2306 | 13.8 | 138 | 12.1 | 27 287 | 22.5 | |
Data missing | 157 | 84 | – | – | 73 | ||||||
Body mass index (kg/m2), mean ± SD | 24.88 ± 4.75 | 0.24 | |||||||||
<30 | 424 259 | 80.0 | 328 719 | 84.0 | 14 192 | 84.7 | 944 | 82.7 | 80 404 | 66.4 | |
≥30 | 67 603 | 12.7 | 52 982 | 13.5 | 2130 | 12.7 | 142 | 12.4 | 12 349 | 10.2 | |
Data missing | 38 596 | 7.3 | 9739 | 2.5 | 442 | 2.6 | 56 | 4.9 | 28 359 | 23.4 | |
Country of birth | <0.01 | ||||||||||
Nordic | 349 385 | 65.9 | 256 205 | 65.5 | 14 539 | 86.7 | 947 | 82.9 | 77 694 | 64.2 | |
Other Europe | 36 343 | 6.9 | 28 704 | 7.3 | 332 | 2.0 | 18 | 1.6 | 7289 | 6.0 | |
Non‐Europe | 89 725 | 16.9 | 72 057 | 18.4 | 699 | 4.2 | 64 | 5.6 | 16 905 | 14.0 | |
Data missing | 55 005 | 10.4 | 34 474 | 8.8 | 1194 | 7.1 | 113 | 9.9 | 19 224 | 15.9 | |
Smoking (yes) | 23 700 | 4.5 | 17 140 | 4.4 | 1785 | 10.6 | 351 | 30.7 | 4424 | 3.7 | <0.01 |
Data missing | 64 410 | 12.1 | 24 024 | 6.1 | 1028 | 6.1 | 88 | 7.7 | 39 270 | 32.4 | |
Education, (years) | <0.01 | ||||||||||
≤9 | 38 394 | 7.2 | 29 652 | 7.6 | 963 | 5.7 | 225 | 19.7 | 7554 | 6.2 | |
9–12 | 227 314 | 42.9 | 173 006 | 44.2 | 6469 | 38.6 | 194 | 17.0 | 47 645 | 39.3 | |
>12 | 167 101 | 31.5 | 124 536 | 31.8 | 6923 | 41.3 | 513 | 44.9 | 35 129 | 29.0 | |
Data missing | 97 649 | 18.4 | 64 246 | 16.4 | 2409 | 14.4 | 210 | 18.4 | 30 784 | 25.4 | |
Occupation | <0.01 | ||||||||||
Employed | 337 246 | 63.6 | 251 853 | 64.3 | 12 797 | 76.3 | 563 | 49.3 | 72 033 | 59.5 | |
Unemployed/on disability benefits | 27 320 | 5.2 | 19 656 | 5.0 | 1124 | 6.7 | 254 | 22.2 | 6286 | 5.2 | |
On parental leave | 36 518 | 6.9 | 28 474 | 7.3 | 122 | 0.7 | 6 | 0.5 | 7916 | 6.5 | |
Student | 51 620 | 9.7 | 39 278 | 10.0 | 1252 | 7.5 | 120 | 10.5 | 10970 | 9.1 | |
Other | 22 049 | 4.2 | 16 926 | 4.3 | 232 | 1.4 | 78 | 6.8 | 4813 | 4.0 | |
Data missing | 55 705 | 10.5 | 35 253 | 9.0 | 1237 | 7.4 | 121 | 10.6 | 19 094 | 15.8 | |
Living condition | <0.01 | ||||||||||
Cohabitant | 463 201 | 87.3 | 359 446 | 91.8 | 14 612 | 87.2 | 754 | 66.0 | 88 389 | 73.0 | |
One‐person household | 10706 | 2.0 | 7810 | 2.0 | 536 | 3.2 | 132 | 11.6 | 2228 | 1.8 | |
Other family situation | 23 958 | 4.5 | 17 717 | 4.5 | 1300 | 7.8 | 222 | 19.4 | 4719 | 3.9 | |
Data missing | 32 593 | 6.1 | 6467 | 1.7 | 316 | 1.9 | 34 | 3.0 | 25 776 | 21.3 | |
Parity | <0.01 | ||||||||||
0 | 217 523 | 41.0 | 159 825 | 40.8 | 13 722 | 81.9 | 972 | 85.1 | 43 004 | 35.5 | |
1–3 | 282 443 | 53.2 | 220 998 | 56.5 | 2982 | 17.8 | 167 | 14.1 | 56 296 | 48.1 | |
≥4 | 13 423 | 2.5 | 10617 | 2.7 | 59 | 0.4 | 3 | 0.3 | 2744 | 2.3 | |
Data missing | 17 069 | 3.2 | – | 1 | – | 17 068 | 14.1 | ||||
Pre‐gestational disorders | |||||||||||
Hypertension | 2479 | 0.5 | 1900 | 0.5 | 64 | 0.4 | 2 | 0.2 | 513 | 0.5 | 0.09 |
Diabetes | 4198 | 0.8 | 2858 | 0.7 | 110 | 0.7 | 9 | 0.8 | 1221 | 1.1 | <0.01 |
Psychiatric disorder | 53 429 | 11.8 | 38 171 | 1.4 | 3452 | 23.7 | 517 | 53.4 | 11 289 | 11.0 | <0.01 |
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Note: Continuous variables presented as mean ± SD. Comparison between groups with Pearson chi‐square test and ANOVA including valid cases expressed in P‐values.
Abbreviations: AUDIT, Alcohol Use Disorders Identification Test; SD, standard deviation.
2.2. Exposures
The exposure was reported alcohol consumption in the year prior to pregnancy, defined as low‐, moderate‐ or high‐risk use, based on AUDIT scores. At the first antenatal visit, the antenatal care provider registers alcohol consumption in accordance with AUDIT. AUDIT is a questionnaire assessing alcohol consumption, drinking behaviors and alcohol‐related problems. In Swedish guidelines,20 0–5 points is considered low‐risk alcohol consumption, 6–13 moderate‐risk, 14–17 high‐risk and 18–40 very high‐risk. Six points or more are considered hazardous consumption. Hazardous consumption (moderate and high‐risk use) was analyzed with low‐risk consumption as a reference group. Due to restricted numbers, high‐risk and very high‐risk groups were merged into one high‐risk group in this study. Pregnancies with missing data from AUDIT were handled as a separate group called no AUDIT.
2.3. Outcomes
Outcomes were divided, respectively, into pregnancy, labor and neonatal outcomes. Pregnancy outcomes included preeclampsia, placental abruption, stillbirth and preterm birth. Preeclampsia and placental abruption were identified by corresponding codes from ICD‐1019 (TableS1). Preterm birth was defined as birth before 37 weeks. Very preterm birth was defined as birth before 32 weeks and moderate preterm as birth between 32 and 36 gestational weeks. Preterm birth was further divided into spontaneous (spontaneous onset of labor) and iatrogenic (induced labor or planned cesarean section) based on onset of labor as described in electronic birth records. In Sweden, for the majority of women, expected date of delivery is based on a second trimester ultrasound.21
Labor and neonatal outcomes included maternal and neonatal infections, low Apgar score, and birth size. Infections were identified using ICD‐10 codes (TableS1). Maternal infections were divided into intrapartum and postpartum infections. Neonatal infections were viral, bacterial, and parasitical (including infected umbilical stump), diagnosed before discharge from hospital after delivery. Low Apgar score was defined as below 7 at 5min in born‐alive and term‐born infants. Birth size was defined as appropriate for gestational age (AGA), small for gestational age (SGA), or large for gestational age (LGA), based on birthweight. SGA was defined as below two standard deviations (SD) of expected birthweight for gestational age and sex, and LGA as two standard deviations above.22
2.4. Statistical analyses
Maternal background characteristics, based on data for all births, were described with absolute and relative frequencies, means with standard deviations, and by AUDIT group (ie low‐, moderate‐, high‐risk or no AUDIT registered). Comparison between AUDIT groups with Pearson chi‐square test and analysis of variance (ANOVA) were made and presented with P‐values in Table1.
Logistic regression analyses were used to estimate associations between moderate‐ and high‐risk alcohol consumption during the year before pregnancy, as well as the group with no AUDIT recorded, adverse maternal and neonatal outcomes, with low‐risk alcohol consumption as the reference group. Point estimates were presented as odds ratios (ORs) with 95% confidence intervals (CIs). Associations between alcohol consumption and severity, as well as type of preterm birth were analyzed with multinominal regression, with term birth as the reference group. Ordinal regression was used for calculating associations with birth size categories, with AGA as the reference group. We used generalized estimating equations (GEE) in all analyses, since observations were not independent (women could have multiple births registered during the study period).
Directed acyclic graphs (DAG) were used to identify potential confounders (Figures[Link], [Link]).23 Age, parity, country of birth, living condition, smoking, and prior or ongoing psychiatric disorder were explanatory variables considered for all outcomes, and included as covariates to calculate adjusted ORs (aORs) with 95% CIs.
All statistical analyses were performed using IBM SPSS Statistics version 26.
2.5. Ethics statement
The Regional Ethical Board at Uppsala approved the study on August 15, 2018 (Dnr 2018/287) with approved amendments 2018/287/1, 2019–04672, 2020–05731, and 2021–01146.
3. RESULTS
Among 530 458 births, 16 764 women reported moderate‐risk consumption of alcohol before pregnancy (3.2%) and 1142 reported high‐risk consumption (0.2%). AUDIT was not recorded for 121 112 births (22.8%). Mean maternal age was 31 years and 66% were of Nordic origin. Smoking was more common in women with hazardous risk consumption. Low education and unemployment were associated with high‐risk use. There was no difference between groups regarding hypertension but psychiatric disorders were more frequently observed among women in the moderate‐risk alcohol use group and particularly in the high‐risk group. Women with missing data for AUDIT were of similar background characteristics to the average for the cohort, but with more missing values on background characteristics (Table1).
3.1. Pregnancy outcomes
Figure1 and TableS2 illustrate associations between alcohol consumption during the year before pregnancy and pregnancy outcomes. Compared with women with low‐risk consumption, women with moderate‐risk consumption had an increased likelihood of preeclampsia before adjustment for maternal and socioeconomic factors. However, after adjustment, a slightly reduced risk (aOR 0.88, 95% CI 0.80–0.96) of preeclampsia was observed among women with moderate‐risk consumption. An association was seen between hazardous alcohol consumption and preterm birth, with 17% and 78% higher odds of preterm birth among women with moderate‐ and high‐risk consumption, respectively. When separating preterm birth by severity (very and moderate preterm) and onset (iatrogenic or spontaneous), associations were observed with moderate preterm and preterm birth of spontaneous onset but not for iatrogenic onset or very preterm. After adjustment for maternal and socioeconomic factors, all associations for preterm birth became non‐significant. TableS2 shows the data generating Figure1, with number, OR and percentage of outcomes in each group including no AUDIT.
FIGURE 1.
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3.2. Labor and neonatal outcomes
Figure2 and TableS3 illustrate associations between alcohol consumption during the year before pregnancy along with labor and neonatal outcomes. Compared with women with low‐risk consumption, women with either moderate‐ or high‐risk consumption had higher risks for infections both during labor and in the neonatal period. After adjusting for the confounders (ie maternal age, parity, country of birth, living condition, smoking habits, history of psychiatric disorder), women with moderate‐ or high‐risk consumption had 29% and 62% higher odds of intrapartum infection, respectively (aOR 1.29, 95% CI 1.17–1.42 and aOR 1.62, 95% CI 1.17–2.25). Neonatal infections had similarly increased odds for moderate‐risk (aOR 1.22, 95% CI 1.07–1.40) and high‐risk alcohol consumption (aOR 1.79, 95% CI 1.21–6.65). An Apgar score below 7 at 5minutes was more common among women with high‐risk consumption (OR 1.69, 95% CI 1.15–2.24), but after adjustment the difference disappeared. Moderate‐ and high‐risk alcohol consumption prior to pregnancy was not an independent risk factor for birthing of an infant small or large for gestational age. TableS3 shows the results generating Figure2, with number, OR and percentage of outcomes in each group including no AUDIT.
FIGURE 2.
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4. DISCUSSION
We found that hazardous alcohol consumption before pregnancy was associated with infections in the mother and neonate. However, after accounting for maternal and socioeconomic factors, the association with preterm birth was non‐significant. Yet, hazardous alcohol consumption prior to pregnancy remained linked to increased odds for maternal infections during delivery, as well as neonatal infections, in a dose–response pattern.
We recognize the strengths and limitations of this study. The SPR is a nationwide register covering more than 91% of births in Sweden and includes self‐reported AUDIT scores, which would limit selection bias. Information on drinking habits was collected before outcomes, controlling recall bias, which is important in studies of behavioral exposures and adverse birth outcomes. Furthermore, the SPR provided information pertaining to selected sociodemographic (eg age, parity, country of birth), economic (living condition etc.), behavioral (smoking) and medical factors (psychiatric disorder etc.). These were considered important confounders, identified using a theoretical framework and directed acyclic graphs, and were therefore possibly accounted for in analyses. A major limitation was lack of information on drinking patterns during pregnancy, which restricts interpretation for time of exposure and biological pathways. Thus, it cannot be ruled out that the results are affected by in utero alcohol exposure. Prior studies indicate that women with hazardous alcohol consumption during the year prior to pregnancy continue to drink until becoming aware of their pregnancy.24 In a Norwegian population‐based study, a periconceptional binge‐drinking episode was reported by one of four women25 and binge drinking within 4 weeks of conception was associated with increased risk for conduct problems in the offspring's childhood.26 In our study, the AUDIT scores were based on self‐reported drinking patterns prior to pregnancy and in more than a fifth of births, no AUDIT point was recorded. Women with missing AUDIT scores were similar to the main cohort in terms of baseline characteristics, but with more missing data in other background factors. The reasons for missing AUDIT scores could be due to administrative drop‐out, omitting the question in maternal healthcare or not responding to the questionnaire. A higher proportion of preterm birth was observed among women with no AUDIT score recorded. This could be explained by the fact that antenatal information is lost for women transferred to a secondary‐ or tertiary‐level hospital, an example of administrative drop‐out. This occurs when risk of preterm birth is diagnosed at a center without capacity for delivery of infants below a specific gestational age.
We believe that there is an underreporting of moderate‐ and high‐risk consumption in our cohort, resulting in small numbers which restrict the precision of results and provide wide confidence intervals. Compared with prior reports, we found a much lower incidence (3.4%) of self‐reported hazardous consumption prior to pregnancy, with 3.2% considered to have moderate‐risk and 0.2% high‐risk consumption. In a Swedish prospective study from 2003 with AUDIT scores anonymously collected at an antenatal clinic, 17.0% of women reported hazardous use of alcohol during the year preceding pregnancy.27 In another Swedish study with a similar study design from 2021, 15.7% of women who chose to be anonymous reported hazardous alcohol use before pregnancy, but only 5.1% of those choosing not to be anonymous.28 A slight decline in alcohol consumption, across all ages, has been observed in Sweden in the last decades29 but alcohol consumption is a stigmatized subject, meaning that anonymously collected data are more reliable. How well AUDIT serves as a screening tool for alcohol consumption during pregnancy is uncertain. Skagerström et al.24 reported from a Swedish multicenter study that a higher proportion of women with high‐risk alcohol consumption in the year prior to pregnancy continued to consume alcohol, whereas moderate drinkers more frequently stopped drinking if planning a pregnancy. A Norwegian population‐based study25 showed that among planned pregnancies (78%), 1.5% reported continued heavy drinking during pregnancy and 39% reported light drinking.
We found increased rates and odds of infections in women with a moderate‐ or high‐risk alcohol consumption prior to pregnancy when compared with low‐risk consumption, indicating alcohol consumption is an independent risk factor for perinatal infections. High intake of alcohol suppresses the immune system, potentially leading to increased susceptibility to infections.6 In an observational study, women were interviewed about their alcohol drinking habits at four different occasions prior to and during pregnancy. Alcohol amount and drinking patterns both prior to and during pregnancy were associated with neonatal infections. After adjustments, excessive drinking (at least 7 drinks/week) in the second trimester increased the risk almost fourfold.30 Other studies11, 12 support the evidence that prenatal alcohol exposure leads to increased rates of neonatal infections. It is possible that the increased risks of infections are caused by a combination of hazardous alcohol intake prior to pregnancy and persistent drinking during pregnancy. The results support screening with AUDIT scores should be used and intervention for women with high scores is to be recommended. Although we have focused on inflammatory‐ and placenta‐mediated disorders, multiple outcomes were investigated and not accounted for in our analysis, which increases the risk of a chance finding. The results and biological pathways need to be confirmed as well.
Since alcohol use has been related to surgical site infections, treatment using alcohol abstinence and cessation programs are an effective consideration to reduce postoperative complications.31
Infection and inflammatory changes during pregnancy are closely linked to preterm birth, with heavy alcohol consumption during pregnancy an established risk factor for preterm birth and low birthweight.3 In our unadjusted analyses, there was an association between hazardous alcohol consumption and preterm birth. However, this association could be attributed to coexisting maternal and socioeconomic factors; the AUDIT score per se could not be regarded as an independent factor in preterm birth. Alcohol consumption is closely linked to demographic and socioeconomic factors, which is an important consideration when assessing birth outcomes. It should be noted that an absence of associations might reflect interventions during pregnancy for hazardous alcohol use found in antenatal screening. Our aim was to focus on placenta‐ and inflammatory‐mediated pregnancy outcomes; therefore such outcomes should not be affected by counseling during pregnancy after placentation.
5. CONCLUSION
Apart from identifying hazardous alcohol consumption prior to pregnancy and offering counseling, screening with the AUDIT in early pregnancy can reveal high risk inflammatory‐/placenta‐mediated pregnancy and birth outcomes. Hazardous alcohol use prior to pregnancy was independently linked to intrapartum and neonatal infections. Such conditions are associated with morbidity and long‐term sequalae. Since the cohort is register‐based and lacks information on alcohol exposure during pregnancy, it is not feasible to explain this association further. Possible explanations for such conditions might be alcohol‐induced changes in the maternal or fetal immune system in early pregnancy, persistent alcohol intake during pregnancy or associated unidentified confounding factors.
AUTHOR CONTRIBUTIONS
JA, SH, and A‐KW conceived the study. JA managed the data and performed the statistical analysis with technical input from SH. JA wrote the first draft. All authors contributed with critical input on analysis, interpretation of data, and the final article.
FUNDING INFORMATION
JA and OA were financed by the Center for Clinical Research, Sörmland. LB was financed by the Swedish Society for Medical Research (SSMF) and the Swedish state under the agreement between the Swedish government and the county councils, the ALF agreement (ALFGBG‐942685). SH was supported by the Center for Clinical Research, Falun (grant CKFUU‐930828), the Swedish Council for Information on Alcohol and Other Drugs (CAN, grant FO 2019–0020) and the Regional Research Council Mid Sweden (grant RFR‐930895).
CONFLICT OF INTEREST
The authors have stated explicitly that there are no conflicts of interest in connection with this article.
Supporting information
Figure S1
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Figure S2
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Figure S3
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Figure S4
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Table S1
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Table S2
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Table S3
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ACKNOWLEDGMENTS
We are grateful for the statistical support provided by Nicklas Pihlström (Center for Clinical Research Sörmland).
Asp J, Bergman L, Lager S, Axelsson O, Wikström A‐K, Hesselman S. Alcohol exposure prior to pregnancy—does hazardous consumption affect placenta‐ and inflammatory‐mediated pregnancy outcomes? A Swedish population‐based cohort study. Acta Obstet Gynecol Scand. 2022;101:1386‐1394. doi: 10.1111/aogs.14451
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Figure S1
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Figure S2
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Figure S3
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Figure S4
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Table S1
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Table S2
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Table S3
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