Maternal health indicators during pregnancy and birth outcomes during times of great macroeconomic instability: the case of Iceland

Background and aims: Macroeconomic fluctuations have shown various effects on population health, but the evidence base for their influence on maternal health and birth outcomes is scarce and inconclusive. The overall aim of this thesis was to examine the potential effect of the 2008 economic collapse in Iceland on maternal diseases and health behaviors during pregnancy as well as on adverse birth outcomes. Furthermore, we aimed to explore the effect of the surrounding economic climate in Iceland on potential changes in the health of the pregnant women and birth outcomes. Material and methods: In study I we used a random sample of 1329 births occurring between 2001, and 2010. Information on maternal smoking status, body mass index and demographic characteristics were retrieved from the Icelandic Medical Birth Registry and maternity records. Trends in continued smoking into the second trimester of pregnancy, obesity, and body mass index were assessed using logistic and linear regression analyses. Logistic regression analysis was used to calculate the annual odds of smoking and obesity, both overall and by maternal demographic characteristics. In studies II-IV, the Icelandic Medical Birth Registry was used to identify all women giving birth to live-born singletons between the years 2002 and 2012 (2006- 2009 for study III). Information on pregnancy-induced hypertensive disorders, birth outcomes, and parental demographic characteristics were retrieved from the Birth Registry and use of antihypertensive drugs during pregnancy, including β-blockers and calcium channel blockers, from the Icelandic Medicines Registry. Information on the aggregate economic climate was retrieved from Statistics Iceland. With the pre-recession period as a reference, we used logistic regression analyses to assess changes in pregnancy-induced hypertensive disorders, prescription fills for antihypertensive drugs and adverse birth outcomes during the recession years. Results: There was an annual decrease in continued smoking (odds ratio (OR) 0.94, 95% confidence interval (CI) 0.88-1.00) among pregnant women in Iceland giving birth during the first decade of the 21st century, whereas no significant changes in obesity were observed (OR 1.02, 95% CI 0.96-1.07). The highest prevalence of maternal smoking and obesity was observed in the years leading up to the economic collapse or in 2005 to 2006. vi With regard to maternal diseases and using the pre-recession period as a reference, we observed an increase in gestational hypertension during the first recession year (OR 1.47, 95% CI 1.13-1.91) with a concurring increase in prescription fills for β-blockers during the same year (OR 1.43, 95% CI 1.07-1.90). The increase was confined to the first recession year and was not observed in the subsequent recession years. Furthermore, the increase disappeared when adjusting for aggregate unemployment rate, indicating that the economic conditions, as proxied by aggregate unemplyment, is the reason for the observed effects. No changes were observed for preeclampsia or in prescription fills for calcium channel blockers between the pre-recession and recession periods. With regard to adverse birth outcomes and using the pre-recession period as a reference, we observed an increase in low birth weight during the first recession year (OR 1.35, 95% CI 1.12-1.63) but not during the subsequent recession years. Furthermore, we noted an increase in small for gestational age births, both during the first recession year (OR 1.11, 95% CI 1.00-1.23) and the subsequent three recession years (OR 1.08, 95% CI 1.01-1.16). The observed increase of low birth weight and small for gestational age births were attenuated when adjusting for aggregate economic indicators. Moreover, the findings indicated infants born to young women, those not cohabitating and parents not working paid labor-market jobs, were at higher risk for these adverse birth outcomes during the recession years compared with their peers during the pre-recession years. No significant change was observed for preterm births between pre-recession and recession periods. Conclusions: The findings of this thesis lend support to the notion that the 2008 economic collapse in Iceland had adverse effects on the health of pregnant women and their offspring in Iceland during the first four years of the economic recession. More specifically, the findings indicate a transient increase in gestational hypertension and in the use of β-blockers during the first and most severe year of the economic recession, as well as a negative influence on fetal growth, which was particularly observed among the most vulnerable groups of the society, resulting in widening disparities in birth outcomes in Iceland during the recession.Inngangur: Sýnt hefur verið fram á að sveiflur á efnahagsástandi þjóða geta haft áhrif á lýðheilsu. Hinsvegar er ekki mikið vitað um áhrif slíkra sveiflna á heilsu mæðra og fæðingarútkomur. Niðurstöður þeirra rannsókna sem gerðar hafa verið hafa verið misvísandi. Meginmarkmið þessa doktorsverkefnis var að rannsaka möguleg áhrif íslenska efnahagshrunsins, haustið 2008, á heilsu barnshafandi kvenna og fæðingarútkomur. Ennfremur að kanna að hversu miklu leyti efnahagsástandið á Íslandi skýrði mögulegar heilsufarsbreytingar hjá ofangreindum konum og afkvæmum þeirra. Efni og aðferðir: Í rannsókn I var notað slembiúrtak úr Fæðingaskrá Íslands sem samanstóð af 1329 konum sem eignuðust börn á tímabilinu 2001 til 2010. Upplýsingum um reykingavenjur á meðgöngu, líkamsþyngdarstuðul og lýðfræðilegar upplýsingar um móður voru fengnar úr Fæðingaskrá og úr mæðraskrám. Notuð var lógistísk og línuleg aðhvarfsgreining til að reikna breytingar á reykingum á meðgöngu, líkamsþyngdarstuðli og offitu eftir árum og eftir lýðfræðilegum bakgrunnsþáttum móður. Í rannsóknum II-IV var Fæðingaskráin notuð til að bera kennsl á allar konur sem fæddu lifandi einbura á árunum 2002 til 2012 (2006-2009 fyrir rannsókn III). Upplýsingum um meðgöngutengda háþrýstingssjúkdóma (meðgönguháþrýstingur, meðgöngueitrun) og óhagstæðar fæðingarútkomur (léttburafæðingar, fyrirburafæðingar, vaxtarskerðing í móðurkviði), auk lýðfræðilegra upplýsinga um móður og föður voru fengnar úr Fæðingaskrá en upplýsingar um notkun háþrýstingslækkandi lyfja (β-blokkar, kalsíumgangalokar) fengust úr Lyfjagagnagrunni. Efnahagsvísar Íslands voru fengnir frá Hagstofu Íslands. Lógistísk aðhvarfsgreining var notuð til að meta breytingar á meðgöngutengdum háþrýstingssjúkdómum og notkun á háþrýstingslækkandi lyfjum, auk breytinga á óhagstæðum fæðingarútkomum á árunum eftir efnahagshrunið, samanborið við árin fyrir hrun. Niðurstöður: Niðurstöðurnar gefa til kynna að árlega hafi dregið úr reykingum (gagnlíkindahlutfall (GLH) 0.94, 95% öryggismörk (ÖM) 0.88-1.00) á meðal ófrískra kvenna á Íslandi á fyrsta áratug aldarinnar. Á sama tíma virðist ekki hafa orðið marktæk breyting á tíðni offitu hjá ófrískum konum (GLH 1.02, 95% ÖM 0.96-1.07). Hæsta tíðni reykinga á meðgöngu og offitu virðist hafa verið í aðdraganda efnahagshrunsins, eða á árunum 2005 til 2006. Niðurstöður er varða heilsu barnhafandi kvenna gefa til kynna að konur sem voru ófrískar á fyrsta árinu eftir hrun voru í aukinni áhættu fyrir iv meðgönguháþrýstingi (GLH 1.47, 95% ÖM 1.13-1.91) samanborið við konur sem voru ófrískar fyrir hrun, með samsvarandi aukningu í notkun β-blokka á þessu sama tímabili (GLH 1.43, 95% ÖM 1.07-1.90). Þessi aukning virðist hafa verið bundin við fyrsta árið eftir hrun og sást ekki þegar lengra dró frá hruni. Ennfremur, þegar leiðrétt var fyrir atvinnuleysisstigi þá hvarf þessi aukning sem gefur til kynna að dýpt kreppunnar, mæld með atvinnuleysisstigi í landinu, sé skýringin á þeim tengslum sem fundust. Engin breyting varð á tíðni meðgöngueitrunar eftir efnahagshrunið, samanborið við árin fyrir hrun. Niðurstöður er varða fæðingaútkomur gefa til kynna aukna áhættu á fæðingum léttbura á fyrsta árinu eftir efnahagshrunið (GLH 1.35, 95% ÖM 1.12-1.63), samanborið við árin fyrir hrun. Þessi aukning virtist vera bundin við fyrsta árið eftir hrun og sást ekki þegar lengra dró frá hruni. Sú aukning sem varð á léttburum eftir hrun virðist að einhverju leyti vera tilkomin vegna vaxtarskerðingar í móðurkviði. Á fyrsta ári eftir hrun varð aukning á vaxtarskertum nýburum (GLH 1.11, 95% ÖM 1.00-1.23) sem virtist vera viðvarandi út rannsóknartímabilið (GLH 1.08, 95% ÖM 1.01-1.16). Þegar leiðrétt var fyrir efnahagsvísum þá hvarf þessi aukning á fæðingum léttbura og vaxtarskertra barna, sem gefur til kynna miðlunaráhrif af efnahagsástandi í landinu. Ennfremur gefa niðurstöðurnar til kynna að börn ungra kvenna, þeirra sem ekki voru í sambúð og foreldra þar sem báðir voru án launaðrar atvinnu, voru í aukinni áhættu á að fæðast of létt eða vaxtarskert í kjölfar efnahagshrunsins samanborið við sömu hópa fyrir hrun. Engar marktækar breytingar urðu á tíðni fyrirburafæðinga eftir hrun, samanborið við fyrir hrun. Ályktun: Niðurstöðurnar gefa til kynna að efnahagshrunið á Íslandi haustið 2008 hafi haft neikvæð áhrif á heilsu barnshafandi kvenna og á fæðingaútkomur þeirra. Nánar tiltekið þá virðist efnahagshrunið hafa valdið aukningu á meðgönguháþrýstingi og notkun háþrýstingslækkandi lyfja á fyrsta og alvarlegasta ári efnahagsþrenginganna, auk þess að hafa haft neikvæð áhrif á vöxt barna í móðurkviði. Neikvæð áhrif efnahagshrunsins á fósturvöxt virðist hafa verið mest hjá viðkvæmustu hópum þjóðfélagsins sem ýtir undir ójöfnuð í fæðingaútkomum eftir þjóðfélagshópum á tímum efnahagsþrenginga. Ólíklegt verður að teljast að neikvæð áhrif efnahagshrunsins á heilsu barnshafandi kvenna og fæðingaútkomur hafi verið miðlað í gegnum verri heilsuhegðun hjá barnshafandi konum.Icelandic Research Fun

Pregnancy-Induced Hypertensive Disorders before and after a National Economic Collapse: A Population Based Cohort Study.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.Data on the potential influence of macroeconomic recessions on maternal diseases during pregnancy are scarce. We aimed to assess potential change in prevalence of pregnancy-induced hypertensive disorders (preeclampsia and gestational hypertension) during the first years of the major national economic recession in Iceland, which started abruptly in October 2008.Women whose pregnancies resulted in live singleton births in Iceland in 2005-2012 constituted the study population (N = 35,211). Data on pregnancy-induced hypertensive disorders were obtained from the Icelandic Medical Birth Register and use of antihypertensive drugs during pregnancy, including β-blockers and calcium channel blockers, from the Icelandic Medicines Register. With the pre-collapse period as reference, we used logistic regression analysis to assess change in pregnancy-induced hypertensive disorders and use of antihypertensives during the first four years after the economic collapse, adjusting for demographic and pregnancy characteristics, taking aggregate economic indicators into account. Compared with the pre-collapse period, we observed an increased prevalence of gestational hypertension in the first year following the economic collapse (2.4% vs. 3.9%; adjusted odds ratio [aOR] 1.47; 95 percent confidence interval [95%CI] 1.13-1.91) but not in the subsequent years. The association disappeared completely when we adjusted for aggregate unemployment rate (aOR 1.04; 95% CI 0.74-1.47). Similarly, there was an increase in prescription fills of β-blockers in the first year following the collapse (1.9% vs.3.1%; aOR 1.43; 95% CI 1.07-1.90), which disappeared after adjusting for aggregate unemployment rate (aOR 1.05; 95% CI 0.72-1.54). No changes were observed for preeclampsia or use of calcium channel blockers between the pre- and post-collapse periods.Our data suggest a transient increased risk of gestational hypertension and use of β-blockers among pregnant women in Iceland in the first and most severe year of the national economic recession.RANNIS/12045202

Low Birth Weight, Small for Gestational Age and Preterm Births before and after the Economic Collapse in Iceland: A Population Based Cohort Study

Objective: Infants born small for gestational age (SGA) or preterm have increased rates of perinatal morbidity and mortality. Stressful events have been suggested as potential contributors to preterm birth (PB) and low birth weight (LBW). We studied the effect of the 2008 economic collapse in Iceland on the risks of adverse birth outcomes. Study design The study population constituted all Icelandic women giving birth to live-born singletons from January 1st 2006 to December 31st 2009. LBW infants were defined as those weighing <2500 grams at birth, PB infants as those born before 37 weeks of gestation and SGA as those with a birth weight for gestational age more than 2 standard deviations (SD's) below the mean according to the Swedish fetal growth curve. We used logistic regression analysis to estimate odds ratios [OR] and corresponding 95 percent confidence intervals [95% CI] of adverse birth outcomes by exposure to calendar time of the economic collapse, i.e. after October 6th 2008. Results: Compared to the preceding period, we observed an increased adjusted odds in LBW-deliveries following the collapse (aOR = 1.24, 95% CI [1.02, 1.52]), particularly among infants born to mothers younger than 25 years (aOR = 1.85, 95% CI [1.25, 2.72]) and not working mothers (aOR = 1.61, 95% CI [1.10, 2.35]). Similarly, we found a tendency towards higher incidence of SGA-births (aOR = 1.14, 95% CI [0.86, 1.51]) particularly among children born to mothers younger than 25 years (aOR = 1.87, 95% CI [1.09, 3.23]) and not working mothers (aOR = 1.86, 95% CI [1.09, 3.17]). No change in risk of PB was observed. The increase of LBW was most distinct 6–9 months after the collapse. Conclusion: The results suggest an increase in risk of LBW shortly after the collapse of the Icelandic national economy. The increase in LBW seems to be driven by reduced fetal growth rate rather than shorter gestation

Tíðni lágrar fæðingarþyngdar, léttbura- og fyrirburafæðinga í kjölfar efnahagshrunsins á Íslandi árið 2008

Infants born small or preterm have increased rates of mortality and morbidity throughout childhood and into adulthood. Stressful events have been suggested as potential contributors to preterm birth (PB) and low birth weight (LBW). We aimed to study the effect of the 2008 national economic collapse in Iceland on the risk of these adverse birth outcomes. The study population constituted all Icelandic women giving birth to live-born singletons from January 1st 2006 to December 31st 2009. LBW infants were defined as those weighing <2500g at birth, PB infants defined as those born before 37 weeks of gestation and small-for-gestational age (SGA) defined as infants with birth weight less than two standard deviation below the mean on a fetal growth curve. Exposure to the collapse of the Icelandic banking system was modeled with calendar time. We used logistic regression to estimate odds ratios [OR] and the corresponding 95 percent confidence intervals [95%CI] of these adverse birth outcomes by exposure to calendar time of the economic crisis, i.e. after October 6th 2008. Compared to the preceding period, we observed a short-term increase in LBW deliveries following the economic collapse (aOR=1.24, 95% CI [1.02, 1.52]), particularly among children born to women younger than 25 years (aOR=1.85, 95% CI [1.25, 2.72]) and mothers not working (aOR=1.59, 95% CI [1.10, 2.31]). Similarly, we found a tendency towards higher incidence of SGA births (aOR=1.14, 95% CI [0.86, 1.51]), particularly among children born to women younger than 25 years (aOR=1.85, 95% CI [1.08, 3.19]) and to women not working (aOR=1.84, 95% CI [1.09, 3.10]). We found no change in the risk of PB. The results suggest a short term increase in incidence of low birth weight following the dramatic collapse of the Icelandic national economy. The increase in LBW seemed driven by reduced fetal growth rate rather than shorter gestation.Börn sem fædd eru of létt eða fyrir tímann eru í aukinni áhættu varðandi nýburadauða auk þess sem þau eiga oft við heilsufarsvandamál að stríða þegar fram líða stundir. Þættir sem hafa verið nefndir sem mögulegir orsakavaldar léttbura- og fyrirburafæðinga eru meðal annars streituvaldandi atburðir og sálræn streita. Markmið þessarar rannsóknar var að skoða áhrif efnahagshrunsins á Íslandi árið 2008 á tíðni léttbura- og fyrirburafæðinga. Rannsóknin náði til allra íslenskra kvenna sem höfðu eignast lifandi fædda einbura á tímabilinu 1. janúar 2006 til 31. desember 2009. Léttburar voru skilgreindir sem börn sem vógu <2500 grömm við fæðingu, fyrirburar sem þau sem fæddust fyrir 37. viku meðgöngu og vaxtarskert börn sem voru undir tveimur staðalfrávikum undir meðalþyngd á fósturvaxtarkúrfu. Útsetning var hrun íslenska bankakerfisins, skilgreint með tíma. Börn sem fæddust eftir hrun eru álitin vera útsett fyrir efnahagshruninu og þau sem fæddust fyrir hrun talin ekki útsett. Lógistísk aðhvarfsgreining var notuð til að meta gagnlíkindahlutfall [OR] og samsvarandi 95 prósent öryggisbil [95% CI] þessara óhagstæðu fæðingaútkomna eftir útsetningu. Það var marktæk skammtíma aukning á léttburafæðingum á tímabilinu eftir hrun, miðað við undanfarandi tímabil (aOR=1.24, 95% CI [1.02, 1.52]), sérstaklega á meðal yngri mæðra (<25 ára)(aOR=1.85, 95% CI [1.25, 2.72]) sem og kvenna sem voru ekki í vinnu (aOR=1.59, 95% CI [1.10, 2.31]). Ennfremur, virðist vera ákveðin tilhneiging í átt að aukinni tíðni vaxtarskertra barna (aOR=1.14, 95% CI [0.86, 1.51]), sérstaklega á meðal yngri mæðra (<25) (aOR=1.85, 95% CI [1.08, 3.19]) sem og mæðra sem ekki voru í vinnu (aOR=1.84, 95% CI [1.09, 3.10]). Engin breyting var á tíðni fyrirburafæðinga á tímabilinu. Niðurstöðurnar benda til skammtíma aukningar á tíðni léttburafæðinga í kjölfar hruns íslenska efnahagskerfisins. Þessi aukning virðist vera tilkomin vegna minni vaxtarhraða fóstra en ekki vegna styttri meðgöngu

Prevalence of prescription fills for β-blockers and calcium channel blockers among pregnant women in Iceland 2005–2012, after gestational week 20.

<p>Prevalence of prescription fills for β-blockers and calcium channel blockers among pregnant women in Iceland 2005–2012, after gestational week 20.</p

The odds ratios [OR] and 95% confidence intervals [CI] of (A) overall pregnancy-induced hypertensive disorders, (B) gestational hypertension and (C) preeclampsia in each of the four post-collapse years following the economic collapse in Iceland compared with pre-collapse period.

<p>* Adjusted for maternal age, gravidity and time in weeks [time-trend].</p><p>** Simultaneously adjusted for maternal age, gravidity, time in weeks, sex, diabetes, pre-existing hypertension, relationship status, place of residence, employment status and citizenship.</p><p>***Adjusted for maternal age, gravidity, time in weeks and aggregate unemployment rate.</p><p>Included in the collapse groups are women with singleton pregnancies with gestational length of 20 weeks or more during ^aSeptember 27^th 2004–September 28^th 2008, ^bSeptember 29^th 2008 –September 27^th 2009, ^cSeptember 28^th 2009 –October 3^rd 2010, ^dOctober 4^th 2010 –October 2^nd 2011, ^eOctober 3^rd 2011 –October 1^st 2012.</p><p>The odds ratios [OR] and 95% confidence intervals [CI] of (A) overall pregnancy-induced hypertensive disorders, (B) gestational hypertension and (C) preeclampsia in each of the four post-collapse years following the economic collapse in Iceland compared with pre-collapse period.</p

The odds ratios [OR] and 95% confidence intervals [CI] of (A) prescription fills for β-blockers and (B) prescription fills for calcium channel blockers in pregnancies during each of the four post-collapse years following the economic collapse in Iceland compared with pre-collapse period.

<p>* Adjusted for maternal age, gravidity and time in weeks [time-trend].</p><p>** Simultaneously adjusted for maternal age, gravidity, time in weeks, sex, diabetes, pre-existing hypertension, relationship status, place of residence, employment status and citizenship.</p><p>***Adjusted for maternal age, gravidity, time in weeks and aggregate unemployment rate.</p><p>Included in the collapse groups are women with singleton pregnancies with gestational length of 20 weeks or more during ^aSeptember 27^th 2004–September 28^th 2008, ^bSeptember 29^th 2008 –September 27^th 2009, ^cSeptember 28^th 2009 –October 3^rd 2010, ^dOctober 4^th 2010 –October 2^nd 2011, ^eOctober 3^rd 2011 –October 1^st 2012</p><p>The odds ratios [OR] and 95% confidence intervals [CI] of (A) prescription fills for β-blockers and (B) prescription fills for calcium channel blockers in pregnancies during each of the four post-collapse years following the economic collapse in Iceland compared with pre-collapse period.</p

Adjusted odds ratio of low birth weight, small-for-gestational age and preterm birth during the study period, before and after Oct 6^th 2008, stratified by maternal characteristics.

*<p>OR adjusted for maternal age; parity and seasonal variation.</p>**<p>Statistically significant difference between the time periods.</p

The separate and combined effect of covariates on the odds ratio of low birth weight, small for gestational age and preterm birth during the two study periods, before and after October 6^th 2008.

α<p>SGA is inherently adjusted for infant's sex.</p>*<p>Odds ratio adjusted for seasonal variation, maternal age and parity.</p>**<p>Odds ratio adjusted for seasonal variation, maternal age, parity, sex, diabetes and hypertension.</p>***<p>Odds ratio adjusted for seasonal variation, maternal age, parity, sex, diabetes, hypertension, relationship status, place of residency and employment status.</p