pregestational type 1 diabetes mellitus is clearly associated with an increased incidence of adverse maternal , fetal , and neonatal outcome [ 14 ] , and several studies in the last two decades have shown that pregestational type 2 diabetes poses an emerging problem , with pregnancy outcomes at least as poor as in women with type 1 diabetes [ 59 ] .
this gains even more importance in view of the global diabetes epidemic which leads to ever increasing numbers of women in the childbearing age with pregestational type 2 diabetes [ 5 , 10 ] . to add to the problem
, pregestational type 2 diabetes is encountered frequently in specific subpopulations in north - western europe , such as recently migrated women from africa , asia , and the middle east .
these women are possibly more prone to suboptimal participation in the health care system because of frequently existing language barriers , generally less financial resources , and low education levels in those immigrant groups . the netherlands can be considered as a representative developed european country with ethnic minorities reflecting economic and social history .
data from an epidemiological study from the netherlands revealed that perinatal mortality is increased in women with a nonnative dutch origin .
therefore , the question rises if ethnicity plays a role in the development of pregnancy complications in women with type 2 diabetes , since the incidence of type 2 diabetes is more common in specific ethnicities .
unfortunately , the possible relation between ethnicity and pregnancy complications in women with type 2 diabetes has received limited attention in western europe .
data from two british studies showed no differences in pregnancy outcome between native british and one single other ethnic ( i.e. , afro - caribbean or indo - asian ) women with type 2 diabetes [ 14 , 15 ] .
however , these studies were not nationwide and compared no mixture of ethnicities . therefore , to elucidate more comprehensively the potential impact of ethnic origin ( and their possible accompanying problems ) on pregnancy outcome , we performed a retrospective multicentre study to assess maternal , fetal , and neonatal outcome in a large group of native and a mixture of nonnative dutch women with pregestational type 2 diabetes from different hospitals spread throughout the netherlands .
we hypothesized that nonnative dutch women with type 2 diabetes had a more unfavourable pregnancy outcome as compared to native dutch women with type 2 diabetes .
a multicentre , retrospective study was performed involving seven large hospitals ( university medical centre groningen , university medical centre utrecht , academic medical centre amsterdam , erasmus medical centre rotterdam , medical centre haaglanden the hague , atrium medical centre heerlen , and meander medical centre amersfoort ) spread around the netherlands . all women with pregestational type 2 diabetes
272 women in whom a singleton pregnancy progressed beyond 20 weeks of gestation and who delivered between january 1997 and august 2009 were included in an anonymised database and subsequently evaluated .  
the diagnosis pregestational type 2 diabetes was accepted when patients were anti - gad antibody negative and/or had never experienced a keto - acidotic episode and the diabetes was being managed with diet alone or oral blood glucose - lowering agents and/or insulin . in the latter case ,
the diagnosis of type 2 diabetes was accepted when treatment with insulin was initiated > 6 months after the initial diagnosis .
patients were divided into native and nonnative dutch groups , which was representative for the socioeconomic history of the netherlands .
patients in the latter group were of north - african , hindu , afro - caribbean , asian , or other nonnative origin .
we retrospectively reviewed all charts and recorded maternal characteristics ( age , body mass index , ethnic origin , alcohol use , smoking habits , and parity ) , duration of diabetes , presence of chronic complications , and preconceptional treatment of diabetes . to assess the potential impact of ethnicity on pregnancy outcome , the origin of the pregnant women was classified as ( 1 ) native dutch and ( 2 ) nonnative dutch .
the size of the different ethnic groups ( i.e. , north - african , hindu or afro - caribbean , etc . ) was too small for adequate statistical analysis of these specific ethnicities .
hba1c ( mmol / mol ) values were recorded and median hba1c was calculated in the periods one year before pregnancy and during the first , second , and third trimesters .  
preeclampsia was defined as a diastolic blood pressure 90  mmhg on two occasions at least four hours apart in the second half of pregnancy in previously normotensive women and de novo albuminuria ( 300  mg/24  h ) . in women with preexisting hypertension , pre - eclampsia
hellp syndrome was defined as platelet count 100    10/l , elevated liver enzymes ( serum alanine aminotransferase > 70  u / l and/or serum aspartate aminotransferase > 70 
u / l ) , and haemolysis characterised by serum lactic dehydrogenase level > 600 
only major congenital malformations , defined as abnormalities that were fatal , required major surgery or resulted in severe organ malfunction or cosmetic defects were recorded and classified as related to the cardiovascular , central nervous , urogenital system , or other systems .
perinatal mortality was defined as fetal loss after 22 weeks of gestation or neonatal loss during the first 28 days after delivery .
large for gestational age ( lga ) was defined as a birth weight above the 90th percentile corrected for gestational age , sex , and parity .  
continuous parameters were expressed as mean  sd when normally distributed and as median ( q1q3 ) in case of a skewed distribution .
the appropriate ( non)parametric tests ( i.e. , independent t - test when normally distributed and mann - whitney u - test in case of a skewed distribution ) were used to compare differences between groups for continuous data and the chi - square or fisher 's exact test for categorical variables . a p value < 0.05 was considered as statistically significant .
all statistical analyses were performed using pasw for windows version 18.0 ( spss , inc . , chicago , il , usa ) .
a total of 287 singleton pregnancies in women with pregestational type 2 diabetes were referred to our centers .
15 pregnancies ended before 20 weeks of gestation , leaving 272 ongoing pregnancies and deliveries ( 11 in amersfoort , 28 in groningen , 72 in utrecht , 65 in amsterdam , 39 in rotterdam , 10 in heerlen , and 47 in the hague ) .
80 pregnancies ( 29.4% ) were from women of native dutch origin and 192 pregnancies were from women of nonnative dutch origin ( 70.6% ) .
the specific origin of nonnative women with pregestational type 2 diabetes was north african in 73 ( 26.8% ) , hindu in 59 ( 21.7% ) , afro - caribbean in 43 ( 15.8% ) , asian in ten ( 3.7% ) and , other nonnative in seven ( 2.6% ) women .
the mean age at conception was 33.0  5.6 ( range 1848 years ) and comparable between native and nonnative dutch women ( 32.9  4.8 versus 33.1  5.9 ; p = 0.829 ) .
the median gestational age ( ga ) at first booking was significantly higher in the nonnative group compared to the native group ( 11.5 ( 8.019.0 ) versus 8.0 ( 6.010.3 ) weeks ; p < 0.001 ) .
there was a significant difference in the use of medication between the two groups : about half of the native women were on insulin , whereas about three - quarters of the nonnative women were on oral glucose - lowering drugs or diet only at presentation ( p < 0.001 ) .
the glycemic control was less favourable in nonnative women as compared to native women before and during pregnancy ( p values 0.04 and < 0.001 , resp . ) , although in itself quite reasonable .
pregnancy outcome of the total study population and between native and nonnative dutch women is shown in table 2 . in the total study population ,
median ga at delivery was 38 weeks ; no data of delivery mode was available in one woman because she was referred to another hospital while in labour .
delivery started spontaneously in 75 ( 27.7% ) women , labour was induced in 131 ( 48.3% ) , women and a primary caesarean section ( cs ) was performed in 65 ( 24.0% ) women .
49 of the 206 women ( 23.7% ) who were planned to deliver vaginally had a secondary cs .
the incidence of cs was significantly higher in native dutch women as compared to nonnative dutch women .
this difference was caused by a higher incidence of primary cs in native dutch women with no difference in the incidence of secondary cs between the two groups .
the other maternal outcome variables were not different between native and nonnative dutch women . 

13 perinatal deaths ( 4.8% ) occurred in the total study group , five fetal and eight neonatal deaths ( table 3 ) .
four ( 31% ) deaths were associated with congenital malformations ; four ( 31% ) infants died before or at a ga of 25 weeks and the remaining five ( 38% ) deaths were due to infection ( n = 1 ) , premature rupture of the membranes ( n = 2 ) , tension pneumothorax ( n = 1 ) , or remained unexplained ( n = 1 ) .
major congenital malformations occurred in 17 ( 6.3% ) infants of the total study population ; the incidence in native and nonnative dutch women was similar .
major congenital malformations involved the cardiovascular system ( n = 7 ) , the central nervous system ( n = 4 ) , urogenital system anomalies ( n = 2 ) , or other structures ( n = 4 ) .
three of these women were on oral glucose - lowering drugs during the first trimester . 

85 ( 31.3% ) infants were large for gestational age in the total study population , with no differences between native and nonnative dutch women .
in contrast to our hypothesis , we showed no differences in pregnancy outcome between native and nonnative dutch women with pregestational type 2 diabetes , with the exception of a higher cs rate in native dutch women .
however , a high incidence of adverse pregnancy outcomes in the complete group of women with pregestational type 2 diabetes living in the netherlands was found .
pregnancy outcome of women with pregestational type 2 diabetes has been studied before and our results are generally in accordance with those reports [ 5 , 79 ] . according to the results of a study on ethnic differences in perinatal mortality in the netherlands
, we expected that outcome in nonnative women with type 2 diabetes would be poorer as compared to native dutch women , for example , linked to cultural or knowledge barriers in some ethnic minorities affecting access to and effectiveness of care .
however , we did not find significant differences in pregnancy outcome ( except for the incidence of cs ) .
these data are in accordance with studies from new zealand and europe [ 14 , 15 , 20 , 21 ] . in the previous european studies ,
et al . from new zealand , three main ethnicities ( i.e. , polynesian , asian , and european women ) were compared .
firstly , we included all ethnicities , although the limited group size forced us to treat them statistically as one group . secondly ,
none of these studies were truly nationwide , while the hospitals participating in our study were spread throughout the netherlands . from these studies and from our data , it can be concluded that in a setting of easy access to and compliance with the local health care system , outcome in nonnative women with pregestational type 2 diabetes can be similar to that in native women with pregestational type 2 diabetes . this easy access to care
might be positively affected by the fact that medical care , for example , in the netherlands is fully reimbursed with insurance coverage for basically all inhabitants , resulting in an absence of any financial barriers to receive medical care .
apparently , potential negative effects of slightly poorer glycemic control and later presentation are offset by the care system .  
the only parameter which differed between native and nonnative dutch women with pregestational type 2 diabetes was the higher incidence of a ( primary ) cs in the native group .
this difference might partly be due to a higher incidence of maternal overweight , which according to us papers is related to the cs incidence [ 22 , 23 ] .
it may also be that women of native dutch origin more often opted and negotiated for a primary cs . the proportion native / nonnative dutch ( i.e. , 29.4% versus 70.6% ) was not representative for the normal dutch population .
firstly , this can be explained by a higher incidence of type 2 diabetes among specific non -
secondly , the hospitals that cooperated to this study are mainly located in the urban areas of the netherlands , where the majority of nonnative dutch people are living .
nevertheless , the pregnancy outcome of all studied women still seems worse than the outcome of the general population . according to our study
possibly , other factors play a pathophysiological role in this process and offer opportunities to improve this adverse outcome .
firstly , general awareness of the necessity of pregnancy planning in women with type 2 diabetes may be less than optimal in the netherlands , since these women are generally seen in long - term community care and only referred to secondary care when already pregnant .
unfortunately , we were unable to report about the preconceptional care of the studied women , due to the retrospective nature of our study . therefore , a prospective study about the effects of preconceptional care and pregnancy planning on pregnancy outcome in women with type 2 diabetes is needed .
secondly , postprandial spikes of the blood glucose levels contribute to a high - normal or a minimally elevated , but acceptable ( 4253  mmol / mol ) , hba1c level . nowadays
, there are novel technical options to improve the glycemic control , like continuous glucose monitoring and insulin pumps [ 1 , 27 ] .
thirdly , several studies indicate that a low socioeconomic status ( ses ) is associated with adverse pregnancy outcomes [ 13 , 28 , 29 ] .
since the incidence of type 2 diabetes is the highest in populations with a low ses , an etiological role of this  risk factor  may be expected in the development of complications during pregnancy among women with pregestational type 2 diabetes .
unfortunately , ses was not sufficiently recorded in our retrospective study and ses should , therefore , be analyzed in future prospective studies .
limitations of our study are the retrospective nature , the limited size of the total study population and of the different ethnic groups , and the possibility of selection bias .
only 272 pregnancies were studied from seven large hospitals covering a representative area in the netherlands , but possibly not fully representative , since four centres are tertiary care centres and three are larger secondary care centres .
this might have led to a selection bias , since patients with a poor obstetrical history are referred to tertiary centres .   in conclusion , this study has demonstrated that ethnicity seems not to be a major issue in the cause of pregnancy complications in women with pregestational type 2 diabetes with easy access to medical care .
more prospective research is needed to validate these results and to pay more attention to possible causative factors like preconceptional care , avoiding postprandial spikes of the blood glucose and socio - economic status , in the development of adverse pregnancy outcome in women with pregestational type 2 diabetes .
 
 objective . to assess the incidence of adverse pregnancy outcome in native and nonnative dutch women with pregestational type 2 diabetes ( t2d ) in a multicenter study in the netherlands 
 . methods . maternal characteristics and pregnancy outcome 
 were retrospectively reviewed and the influence of ethnicity on outcome was evaluated using independent t - test , mann - whitney u - test , and chi - square test . results . 272 pregnant women ( 80 native and 192 non - native dutch ) with pregestational t2d were included . 
 overall outcome was unfavourable , with a perinatal mortality of 4.8% , major congenital malformations of 6.3% , preeclampsia of 11% , preterm birth of 19% , birth weight > 90th percentile of 32% , and a caesarean section rate of 42% . 
 in nonnative dutch women , the glycemic control was slightly poorer and the gestational age at booking somewhat later as compared to native dutch women . 
 however , there were no differences in incidence of preeclampsia / hellp , preterm birth , perinatal mortality , macrosomia , and congenital malformations between those two groups . 
 conclusions . a high incidence of adverse pregnancy outcomes was found in women with pregestational t2d , although the outcome was comparable between native and non - native dutch women . 
 this suggests that easy access to and adequate participation in the local health care systems contribute to these comparable outcomes , offsetting potential disadvantages in the non - native group . 
1. Introduction
2. Methods
3. Results
4. Discussion