Maternal Pregestational Diabetes Mellitus and Neural Tube Defects in the Offspring: Findings from Nationwide Registries in Finland from 2000-2014 Open Access

Mowla, Sanjida (Spring 2019)

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BACKGROUND: Neural tube defects (NTDs) are the second most common birth defects globally and contribute to child morbidity and mortality. Pregestational diabetes mellitus (PGDM) has been reported as one of the risk factors for NTDs. The purpose of this study was to estimate the prevalence of PGDM and its association with NTDs, including spina bifida, anencephaly, and encephalocele, among live births and stillbirths in Finland.  

METHODS: We conducted a population-based case-control study in Finland including live births and stillbirths occurring from 2000-2014. We linked three national health registers: the Finnish Hospital Discharge Register (FHDR), the Medical Birth Register (MBR) and the Register of Congenital Malformations (RCM). We also used census data from Statistics Finland. We estimated prevalence of PGDM, and its association with any NTDs (n=240) and isolated NTDs (n=144). The association between PGDM and NTDs was assessed using multivariable logistic regression. We estimated adjusted odds ratios (aORs) and 95% confidence intervals using multivariable logistic regression.

RESULTS: Of the 876,912 births considered for this study, 240 (0.03%) births resulted in an NTD while the remaining 876,672 (99%) live births and stillbirths without NTDs were considered to be controls in our analysis. Of the births examined, 4,112 births (0.47%) occurred among mothers with PGDM; 0.47% of control births were affected by PGDM while 1.67% of case births were affected by PGDM. Among cases, 144 (60%) births had an isolated NTD. After adjusting for potential confounders, PGDM was significantly associated with any NTD (aOR=3.25; 95% CI: 1.03, 10.27). This association was marginally significant for isolated NTDs (aOR=3.34; 95% CI: 0.82, 13.69).

CONCLUSIONS: Our analyses indicate that PGDM is significantly associated with NTDs among live births in Finland. Data on all birth outcomes, including terminations, is necessary for future studies examining this association in Finland. Meanwhile, PGDM should be monitored and timely treatments engaged. Proper glucose control and intake of folic acid before and during pregnancy is an effective preventative measure that should be encouraged among women of reproductive age in Finland. 

Table of Contents

Chapter 1: Overview and Public Health Significance                                                          

Chapter 2: Background and Literature Review                                                                     

     I.        Neural Tube Defects                                                                                                         

   II.        Etiology of NTDs                                                                                                              

 III.        Diabetes Mellitus and Risk of NTDs                                                                              

Chapter 3: Methods                                                                                                                   

     I.        Data Sources                                                                                                                    

   II.        Study Population                                                                                                            

 III.        NTD Cases                                                                                                                       

 IV.        Controls                                                                                                                           

  V.        Exposure Variable                                                                                                          

 VI.        Co-Variables                                                                                                                                

VII.        Statistical Analysis                                                                                                           

Chapter 4: Results                                                                                                                     

Chapter 5: Conclusions and Recommendations                                                                 


Table 1                                                                                                                                         

Table 2                                                                                                                                          

Table 3                                                                                                                                          

Appendix A                                                                                                                                

Appendix B                                                                                                                                  

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